Renal & Urinary

Renal cell carcinoma: presentation and management

Clinical Overview and When to Suspect Renal Cell Carcinoma

— Cigarette smoking (doubles risk)

— Obesity, hypertension, and chronic NSAID/analgesic exposure

— Acquired cystic kidney disease in ESRD/dialysis patients (up to 30-fold risk)

— Occupational exposure to trichloroethylene, cadmium, asbestos

— Hereditary syndromes: von Hippel-Lindau (clear cell), hereditary papillary RCC (MET), Birt-Hogg-Dubé (chromophobe/oncocytoma), hereditary leiomyomatosis-RCC (fumarate hydratase), tuberous sclerosis

— Incidental solid enhancing renal mass on CT/US done for back pain, trauma, or abdominal complaints

— Painless hematuria (gross or microscopic) in an adult >40, especially a smoker

— Unexplained paraneoplastic findings: erythrocytosis, hypercalcemia, hepatic dysfunction without metastases (Stauffer syndrome), refractory hypertension

— New left-sided varicocele that fails to decompress when supine (suggests renal vein/IVC tumor thrombus)

— Constitutional symptoms — weight loss, fevers, night sweats — in a patient with a flank mass

Renal cell carcinoma (RCC) accounts for ~90% of adult kidney cancers and ~3-4% of all adult malignancies in the US; clear cell histology dominates (~75%), followed by papillary and chromophobe subtypes.

Median age at diagnosis is 64, with a 2:1 male predominance. Incidence has been rising, largely driven by incidental detection on cross-sectional imaging done for unrelated indications.

Major risk factors to recognize on a stem:

When to suspect RCC on Step 3:

Board pearl: The classic triad of flank pain + hematuria + palpable mass occurs in <10% of patients and almost always signals advanced disease; the modern "presentation" is an asymptomatic incidentaloma.

Step 3 management: Any solid enhancing renal mass >1 cm on imaging is RCC until proven otherwise — proceed directly to dedicated multiphase CT or MRI urography rather than dismissing as a cyst, and refer to urology.

Presentation Patterns and Key History

— Hematuria (40%) — typically painless, intermittent, gross or microscopic; pelvicalyceal invasion produces clots and colicky pain

— Flank or back pain (40%) — dull, persistent; acute pain suggests hemorrhage into the tumor

— Palpable abdominal/flank mass (25%) — usually large tumors in thin patients

— Left-sided varicocele — renal vein occlusion blocks gonadal vein drainage

— Lower extremity edema, ascites, hepatic congestion — IVC tumor thrombus extending into right atrium

— Anemia of chronic disease (most common) — but also erythrocytosis from ectopic EPO (~5%)

— Hypercalcemia — PTHrP or osteolytic mets

— Hypertension — renin production or AV shunting within tumor

— Stauffer syndrome — reversible nonmetastatic hepatic dysfunction with elevated alk phos, prolonged PT; resolves after nephrectomy

— Cachexia, fever, night sweats, elevated ESR

Incidental presentation (>60% today): Mass found on CT abdomen/pelvis ordered for trauma, appendicitis workup, low back pain, or AAA screening. Patient is asymptomatic; the only clue is the prior imaging study mentioned in the stem.

Local/symptomatic presentation:

Paraneoplastic syndromes (20-30%):

Metastatic presentation (~25% at diagnosis): lung (most common), bone (osteolytic, painful), liver, brain, contralateral kidney, adrenal.

Key history to elicit: smoking pack-years, occupational exposures, family history of kidney/skin/uterine tumors (hereditary syndromes), dialysis vintage, analgesic use, and prior imaging that may have shown a cyst now being re-evaluated.

Board pearl: A new varicocele in an older man — especially right-sided (which never occurs benignly because the right gonadal vein drains directly into IVC) — mandates abdominal imaging to exclude RCC or retroperitoneal mass.

Key distinction: Hematuria in RCC is typically painless; painful hematuria with colic suggests stones or ureteral clot from upper-tract urothelial carcinoma.

Physical Exam Findings and Hemodynamic Assessment

— Hypertension — present in ~40%; may be paraneoplastic (renin) or from renal parenchymal compression

— Tachycardia — anemia or hyperdynamic state from AV shunting

— Resting hypoxia or tachypnea raises concern for pulmonary metastases or tumor pulmonary embolism from IVC thrombus

— Palpable firm, non-tender flank mass that moves with respiration (kidneys are retroperitoneal but large RCCs displace anteriorly)

— Bruit over the mass — high-flow tumor vasculature

— Hepatomegaly without obvious metastases suggests Stauffer syndrome

— Ascites with distended abdominal wall veins — IVC obstruction

— Varicocele that does NOT decompress when supine is the classic finding — venous obstruction rather than valvular incompetence

— Right-sided varicocele is always pathologic until proven otherwise

— Bilateral lower extremity edema → IVC thrombus

— Cutaneous metastases (rare but pathognomonic on boards) — vascular nodules on scalp/face

— Skin findings of hereditary syndromes: retinal hemangioblastomas/CNS lesions (VHL), fibrofolliculomas of face/neck (Birt-Hogg-Dubé), cutaneous leiomyomas (HLRCC)

General appearance: Often unremarkable in early/incidental disease. In advanced cases, look for temporal wasting, pallor, cachexia, and signs of paraneoplastic fever.

Vital signs:

Abdominal exam:

Genitourinary exam:

Extremities and skin:

Cardiopulmonary: New murmur or right heart failure signs in IVC/atrial tumor thrombus; bone tenderness suggests osseous mets.

Hemodynamic assessment: Most RCC patients are euvolemic at presentation. Hypotension is a red flag — consider tumor hemorrhage (Wunderlich syndrome: spontaneous perinephric/retroperitoneal hemorrhage) requiring emergent imaging and possible embolization.

CCS pearl: A patient with flank mass + dropping hemoglobin + flank ecchymosis (Grey-Turner) → order stat noncontrast CT and type and crossmatch, consult IR for angioembolization, then urology — do not delay for elective workup.

Diagnostic Workup — Initial Labs and Imaging

— CBC — anemia (chronic disease) or polycythemia (ectopic EPO)

— CMP — creatinine/eGFR (baseline renal function before nephrectomy), calcium (paraneoplastic), LFTs (Stauffer or hepatic mets), alkaline phosphatase (bone/liver mets)

— LDH — prognostic in metastatic disease (IMDC risk model)

— Urinalysis — hematuria; also screens for proteinuria suggesting alternate diagnosis

— Coagulation studies and PT/INR — preoperative and to detect Stauffer-related coagulopathy

— PTH and PTHrP if hypercalcemic

— Multiphase contrast-enhanced CT abdomen/pelvis is the test of choice: noncontrast, corticomedullary, nephrographic, and excretory phases

— A renal mass enhancing by ≥15-20 Hounsfield units after contrast is considered a solid mass and presumed malignant until proven otherwise

— MRI abdomen with gadolinium when iodinated contrast is contraindicated (eGFR <30, allergy), for characterizing complex cysts, or for evaluating IVC tumor thrombus extent (level I-IV)

— Renal ultrasound distinguishes simple cyst from solid/complex mass but is insufficient for staging

— I and II: benign, no follow-up

— IIF: surveillance imaging at 6-12 months

— III: ~50% malignant — surgical excision

— IV: ~90% malignant — surgical excision

— CT chest for pulmonary metastases (mandatory)

— Bone scan or MRI only if bone pain or elevated alk phos

— MRI brain only if neurologic symptoms

Initial laboratory panel:

Imaging — the cornerstone of RCC diagnosis:

Bosniak classification of cystic renal masses (CT-based):

Staging imaging once RCC suspected:

Board pearl: A renal lesion with macroscopic fat on CT (negative Hounsfield units) is an angiomyolipoma, not RCC — except in tuberous sclerosis where both can coexist.

Step 3 management: Do not biopsy a typical solid enhancing renal mass before nephrectomy in a surgical candidate — imaging features alone justify resection, and biopsy adds bleeding/seeding risk without changing management.

Diagnostic Workup — Advanced and Confirmatory Studies

— Indications: small renal mass considered for active surveillance or ablation, suspected metastasis to kidney (lymphoma, lung cancer history), suspected renal abscess or infection, or unresectable disease where histology guides systemic therapy

— Avoid in cystic masses (low yield, seeding risk) and when imaging is diagnostic and patient is a surgical candidate

— Clear cell (75%): VHL gene loss on chromosome 3p; responds to anti-VEGF therapy

— Papillary type 1: indolent; type 2: aggressive, associated with HLRCC syndrome

— Chromophobe: best prognosis; Birt-Hogg-Dubé association

— Collecting duct and medullary RCC: rare, aggressive; medullary RCC in sickle cell trait patients

— MRI or CT venography defines cephalad extent — critical for surgical planning

— Level I (renal vein), II (infrahepatic IVC), III (intrahepatic/retrohepatic), IV (above diaphragm/atrium)

— Atrial-level thrombus often requires cardiopulmonary bypass during nephrectomy

— Age <46 at diagnosis, bilateral/multifocal RCC, family history of RCC or syndromic features, papillary type 1 or 2, chromophobe with skin findings

— T1: ≤7 cm confined to kidney (a ≤4 cm, b >4-7 cm)

— T2: >7 cm confined

— T3: extends to renal vein/IVC or perinephric fat (not adrenal); T4: beyond Gerota fascia or ipsilateral adrenal

Renal mass biopsy (percutaneous core needle): Reserved for specific scenarios — do not order reflexively.

Histologic subtypes and behavior:

IVC tumor thrombus evaluation:

PET-CT: Not routinely used — RCC has variable FDG avidity. May aid in detecting occult metastases or characterizing indeterminate lesions.

Genetic testing referral when stem suggests heredity:

TNM staging summary (AJCC 8th edition):

Key distinction: Oncocytoma is benign but indistinguishable from chromophobe RCC on imaging or even biopsy in many cases — most are still resected. Don't be tricked by a stem describing "central scar" on a small lesion as definitive.

Board pearl: A young Black patient with sickle cell trait presenting with hematuria and a centrally located, infiltrative renal mass — think renal medullary carcinoma, highly aggressive, often metastatic at diagnosis.

Risk Stratification and First-Line Management Logic

— T1a (≤4 cm): Partial nephrectomy is preferred whenever technically feasible — preserves renal function, equivalent oncologic outcomes

— T1b (4-7 cm): Partial nephrectomy if feasible; otherwise radical nephrectomy

— T2-T3: Radical nephrectomy ± lymph node dissection ± IVC thrombectomy

— Ipsilateral adrenalectomy only if adrenal involvement on imaging or large upper-pole tumor

— Active surveillance with serial imaging: elderly, frail, severe comorbidities, life expectancy <5 years, tumors growing <5 mm/year

— Thermal ablation (cryoablation or radiofrequency): patients unfit for surgery; requires pre-procedure biopsy

— Risk stratify by IMDC (Heng) criteria — 6 factors: Karnofsky <80%, time from diagnosis to systemic therapy <1 year, anemia, hypercalcemia, neutrophilia, thrombocytosis

— Favorable risk (0 factors), intermediate (1-2), poor (≥3) — drives systemic therapy choice and prognosis

— Reserved for good performance status, low-volume metastases, and favorable/intermediate IMDC risk — not routine since CARMENA trial

— Consider after systemic therapy response (deferred cytoreduction)

Localized disease (Stage I-III, T1-T3, N0M0) — surgery is curative intent:

Small renal masses (<4 cm) — alternatives for selected patients:

Advanced/metastatic disease (Stage IV):

Cytoreductive nephrectomy in metastatic RCC:

Metastasectomy: Solitary or oligometastatic lesions (lung, bone) may benefit from resection or stereotactic radiation, especially with long disease-free interval

Step 3 management: A 65-year-old with an incidentally found 3 cm enhancing renal mass and eGFR 55 → partial nephrectomy to preserve nephrons; do NOT default to radical resection — postoperative CKD progression worsens cardiovascular mortality.

Board pearl: RCC is notoriously chemotherapy- and radiation-resistant. Cytotoxic chemo has no first-line role; radiation is palliative only (bone/brain mets, symptom control).

Key distinction: Stage I-III → surgical cure pathway. Stage IV → systemic therapy ± palliative surgery, with prognosis driven by IMDC risk class.

Pharmacotherapy — First-Line Systemic Regimens

— Pembrolizumab + axitinib, pembrolizumab + lenvatinib, or nivolumab + cabozantinib — all PD-1 inhibitor + VEGF TKI doublets

— Single-agent TKI (sunitinib, pazopanib) still acceptable in patients ineligible for immunotherapy

— Ipilimumab + nivolumab (dual checkpoint, CTLA-4 + PD-1) — preferred when durable response desired

— Or any of the ICI-TKI combinations above

— VEGF receptor TKIs: sunitinib, pazopanib, axitinib, cabozantinib, lenvatinib — inhibit angiogenesis (VHL/HIF pathway dependent)

— mTOR inhibitors: everolimus, temsirolimus — second/third-line

— PD-1 inhibitors: nivolumab, pembrolizumab

— CTLA-4 inhibitor: ipilimumab

— HIF-2α inhibitor: belzutifan — approved for VHL-associated RCC and refractory metastatic clear cell RCC

— TKIs: hypertension (often first sign of efficacy — treat with amlodipine/ACEi rather than stopping drug), hand-foot syndrome, hypothyroidism, proteinuria, QT prolongation, diarrhea, fatigue

— ICIs: immune-related adverse events — colitis, pneumonitis, hepatitis, hypophysitis, thyroiditis, type 1 diabetes; manage with corticosteroids ± drug hold

— Sunitinib in particular: hypothyroidism (check TSH q3 months)

First-line systemic therapy for metastatic clear cell RCC in 2024 is built on immune checkpoint inhibitor (ICI) combinations — not single-agent TKIs.

IMDC favorable-risk patients:

IMDC intermediate/poor-risk patients:

Key agents and mechanisms:

Key toxicities to monitor (high-yield Step 3):

Non-clear cell RCC: Limited data; cabozantinib monotherapy or cabozantinib + nivolumab favored; consider clinical trial enrollment.

Step 3 management: New hypertension after starting sunitinib → add or intensify antihypertensive rather than reduce the TKI dose; persistent BP control predicts better tumor response.

Board pearl: Any new symptom in a patient on an ICI — diarrhea, dyspnea, fatigue with low cortisol — get TSH, cortisol, LFTs, lipase, and consider holding the drug plus high-dose steroids for grade ≥2 toxicity.

Procedures and Surgical Management

— Indications: cT1 tumors (≤7 cm), solitary kidney, bilateral RCC, CKD, hereditary RCC syndromes

— Approach: open, laparoscopic, or robot-assisted — robotic now standard at high-volume centers

— Outcomes: equivalent cancer-specific survival vs radical for T1; better preservation of GFR

— Indications: T2 disease, central tumors not amenable to partial, tumor in renal vein/IVC, locally advanced disease

— En bloc resection includes Gerota fascia, perinephric fat, ± regional lymph nodes

— Adrenalectomy only if direct invasion, large upper-pole tumor, or imaging-suspicious adrenal

— Level III/IV thrombi may need vascular surgery, hepatic mobilization, or cardiopulmonary bypass with deep hypothermic circulatory arrest

— Preoperative IVC filter placement is generally contraindicated (risk of tumor entrapment, embolization)

— Small (<3 cm), peripheral, exophytic lesions in patients unfit for surgery

— Higher local recurrence than surgery; requires post-procedure imaging surveillance

— Emerging option for non-surgical candidates with localized disease

— Established role for palliation of bone/brain/spinal metastases

— Preoperative for very large/vascular tumors to reduce blood loss

— Emergent for Wunderlich syndrome (spontaneous retroperitoneal hemorrhage)

— Palliation of intractable hematuria in unresectable disease

— VTE prophylaxis (RCC is highly thrombogenic, especially with IVC thrombus)

— Pre-op iron/anemia optimization

— Counsel patients on postoperative CKD risk — even partial nephrectomy drops GFR by ~10%

Partial nephrectomy (nephron-sparing surgery):

Radical nephrectomy:

IVC tumor thrombectomy:

Thermal ablation (cryo or RFA):

Stereotactic body radiation therapy (SBRT):

Transarterial embolization:

Perioperative considerations:

CCS pearl: Post-nephrectomy patient day 1 with sudden hypoxia and tachycardia → order CT pulmonary angiogram (tumor or thromboembolism), start therapeutic anticoagulation if confirmed PE and no active bleeding, page surgery.

Board pearl: Adjuvant pembrolizumab is FDA-approved post-nephrectomy for intermediate-high risk clear cell RCC (KEYNOTE-564) — disease-free survival benefit; ask about it on stems describing a high-risk resected patient.

Special Populations — Elderly and Renal/Hepatic Impairment

— Many have indolent biology with growth rates <5 mm/year

— Active surveillance with serial imaging (CT or MRI every 6 months initially, then annually) is appropriate if life expectancy <5-10 years

— Competing comorbidities often outweigh RCC mortality risk

— Functional assessment (Karnofsky, ECOG, geriatric assessment) guides surgical candidacy more than chronologic age

— Partial nephrectomy strongly preferred — every 10 mL/min drop in GFR increases cardiovascular mortality

— Avoid iodinated contrast when possible; use MRI without gadolinium or with macrocyclic gadolinium agents if eGFR 30-60

— Gadolinium contraindicated if eGFR <30 (NSF risk with older agents)

— Screen with renal US or MRI every 1-2 years after 3-5 years on dialysis

— RCC tends to be multifocal and bilateral; lower-stage at diagnosis but higher cumulative incidence

— Nephrectomy is curative without GFR concerns; may be done before transplant

— Increased RCC risk in native kidneys

— Switching from calcineurin inhibitors to mTOR inhibitors (sirolimus, everolimus) may reduce RCC recurrence — and these drugs themselves have anti-RCC activity

— Most TKIs are hepatically metabolized — sunitinib, pazopanib, cabozantinib all require dose reduction in moderate-severe hepatic impairment

— Monitor LFTs every 2-4 weeks during initial therapy; pazopanib carries a black box warning for hepatotoxicity

— ICIs are not hepatically dosed but cause immune hepatitis in 5-10%

— Most TKIs do not require renal adjustment

— Avoid temsirolimus and cisplatin-containing regimens in severe CKD

Elderly patients (>75) with small renal masses:

Preexisting CKD:

Patients on dialysis / ESRD with acquired cystic kidney disease:

Post-transplant patients on immunosuppression:

Hepatic impairment:

Renal dose adjustments for systemic therapy:

Step 3 management: An 82-year-old with a 2 cm enhancing renal mass, dementia, and CHF — recommend active surveillance with imaging every 6 months and shared decision-making; do not reflexively refer for nephrectomy.

Board pearl: A 5-year dialysis patient with new hematuria → screen for acquired cystic disease–associated RCC with cross-sectional imaging, not just ultrasound.

Special Populations — Pregnancy, Pediatric, and Hereditary Syndromes

— RCC in pregnancy is rare (~10 case-reports per year); flank mass or hematuria may be misattributed to pregnancy physiology

— Ultrasound and MRI without gadolinium are imaging modalities of choice

— Management depends on gestational age and tumor stage: nephrectomy is feasible in any trimester; second trimester preferred for elective surgery

— Avoid iodinated contrast (TSH suppression risk in fetus) and gadolinium (fetal risk) when alternatives exist

— Multidisciplinary maternal-fetal medicine and urologic oncology coordination

— Wilms tumor (nephroblastoma) is the most common pediatric renal malignancy (peak age 3-4) — NOT RCC

— RCC in children/adolescents is rare and often associated with MiT family translocations (Xp11.2/TFE3) — aggressive

— Pediatric RCC more likely to be hereditary — refer for genetic testing

— Von Hippel-Lindau: clear cell RCC + retinal/CNS hemangioblastomas + pheochromocytomas + pancreatic cysts/NETs; bilateral/multifocal; surgery only when largest tumor reaches 3 cm threshold to preserve nephrons; belzutifan is approved for VHL-associated RCC

— Hereditary papillary RCC (MET mutation): type 1 papillary, multifocal

— Hereditary leiomyomatosis-RCC (FH mutation): cutaneous and uterine leiomyomas + aggressive type 2 papillary RCC — early surgery even for small tumors

— Birt-Hogg-Dubé (FLCN): fibrofolliculomas, lung cysts/spontaneous pneumothorax, chromophobe RCC/oncocytoma

— Tuberous sclerosis: angiomyolipomas + RCC

— First-degree relatives of affected individuals should undergo genetic counseling and serial renal imaging starting in adolescence/young adulthood depending on syndrome

Pregnancy:

Pediatric renal masses:

Hereditary RCC syndromes (high-yield):

Family screening:

Step 3 management: Recurrent pneumothorax + facial papules + bilateral chromophobe-appearing renal tumors → Birt-Hogg-Dubé; refer family for FLCN testing.

Board pearl: In VHL-associated RCC, defer surgery until the largest renal lesion reaches 3 cm — the "3 cm rule" balances metastasis risk against repeated partial nephrectomies and CKD progression.

Complications and Adverse Outcomes

— Spontaneous hemorrhage (Wunderlich syndrome): acute flank pain, hypotension, Grey-Turner sign; requires urgent CT and angioembolization

— IVC tumor thrombus — extends in ~10% of cases; risk of PE, Budd-Chiari (intrahepatic IVC), right heart failure, sudden death from tumor embolism

— Pathologic fracture from osteolytic bone metastases — often weight-bearing bones; consider prophylactic fixation if Mirels score ≥8

— Cord compression from vertebral metastases — neurosurgical emergency

— Brain metastases — seizure, focal deficit, headache

— Severe hypercalcemia with AKI, altered mental status — treat with IV fluids, calcitonin, zoledronic acid; address underlying tumor

— Erythrocytosis with thrombosis risk

— Stauffer syndrome — usually reversible after nephrectomy

— Hypertensive crisis from renin-secreting tumors

— Post-nephrectomy AKI / CKD progression — even partial nephrectomy drops GFR

— Surgical: bleeding, urine leak, ileus, pneumothorax, adjacent organ injury, VTE

— TKI toxicity: severe hypertension, hand-foot syndrome, fistulas/perforation (cabozantinib), thyroid dysfunction, proteinuria, posterior reversible encephalopathy syndrome (PRES), MI, QT prolongation

— ICI toxicity (irAEs): colitis with perforation, pneumonitis, fulminant hepatitis, type 1 DM with DKA, adrenal insufficiency, myocarditis, myasthenic crisis

— 20-40% of resected localized RCC recur — most commonly in lungs, then bone, liver, and surgical bed

— Median time to recurrence ~2 years but late recurrences (>10 years) are characteristic of RCC

Tumor-related complications:

Paraneoplastic complications:

Treatment-related complications:

Disease recurrence:

CCS pearl: ICI-induced myocarditis is rare but fatal — patient on nivolumab/ipi with new chest pain or arrhythmia → troponin, BNP, ECG, echo, MRI; hold drug, start high-dose IV methylprednisolone, admit to cardiology/ICU.

Board pearl: Sudden new-onset hypertension or seizure in a patient recently started on a VEGF TKI → consider PRES — get MRI brain, hold drug, control BP aggressively.

When to Escalate Care — ICU, Consultation, and Inpatient Triage

— Massive hemorrhage (Wunderlich syndrome or post-operative bleed) — type and cross, transfuse, urgent IR/urology

— Tumor embolism from IVC thrombus — PE with hemodynamic compromise → ICU, anticoagulation if no bleeding, surgical consult

— Hypercalcemic crisis (Ca >14 or symptomatic) — IV NS at 200-300 mL/hr, calcitonin, zoledronic acid, admit telemetry

— Spinal cord compression — IV dexamethasone, emergent MRI, neurosurgery and radiation oncology

— ICI-induced fulminant complications — myocarditis, pneumonitis grade 4, hepatitis with INR rise — ICU, methylprednisolone 1-2 mg/kg, hold immunotherapy

— Hypertensive emergency on TKI with end-organ injury — IV antihypertensives, hold drug

— Urologic oncology for any newly diagnosed solid renal mass

— Medical oncology for metastatic, recurrent, or adjuvant-eligible disease

— Radiation oncology for symptomatic bone/brain mets or SBRT candidacy

— Vascular and cardiothoracic surgery for level III-IV IVC thrombus

— Genetic counseling for suspected hereditary syndromes, age <46, bilateral/multifocal disease, or syndromic features

— Palliative care early in advanced disease and at any inflection point

— Most asymptomatic renal masses → outpatient urology referral, no admission needed

— Admit if hematuria with hemodynamic instability, intractable pain, paraneoplastic crisis, or imaging suggesting acute complication

— Post-nephrectomy discharge: follow-up urology in 2-4 weeks, surveillance imaging schedule, BP and renal function check

— On systemic therapy: oncology nurse navigator, urgent triage line for irAEs, ED education for fever/diarrhea

Emergent presentations requiring immediate inpatient/ICU admission:

Required consultations:

Inpatient vs outpatient workup of incidental renal mass:

Transition of care points:

CCS pearl: Patient on ipi/nivo presents to ED with 8 watery stools/day → check stool studies + CMV, hold ICI, start methylprednisolone 1-2 mg/kg IV, consult GI for endoscopy; do not give antidiarrheals as first-line — colitis can perforate.

Step 3 management: Sudden left-sided weakness in a metastatic RCC patient → STAT non-contrast head CT to rule out hemorrhage (RCC mets are classically hemorrhagic), then MRI with contrast; consult neurosurgery and radiation oncology.

Key Differentials — Same-Category (Renal Masses)

— Anechoic on US, no septations, no enhancement

— Extremely common; no follow-up needed

— Distinguishing feature: no enhancement on CT (<15 HU change)

— Benign mesenchymal tumor with macroscopic fat (negative HU on CT)

— Associated with tuberous sclerosis (multiple, bilateral) and lymphangioleiomyomatosis

— Risk of spontaneous hemorrhage if >4 cm — selective arterial embolization or partial nephrectomy

— Epithelioid variant can be malignant

— Benign; classically shows central stellate scar on imaging — but indistinguishable from chromophobe RCC on biopsy

— Most are still resected because of diagnostic uncertainty

— Central, infiltrative, filling defect in collecting system

— Risk factors: smoking, aniline dyes, cyclophosphamide, aristolochic acid, Lynch syndrome

— Presents with painless gross hematuria and possibly hydronephrosis

— Cytology, ureteroscopy, and biopsy required; managed with nephroureterectomy

— Usually bilateral, multifocal, infiltrative; from systemic NHL

— Often homogeneous, less vascular; biopsy-driven diagnosis

— Treat with chemotherapy, not surgery

— From lung, breast, melanoma, GI primaries

— Often bilateral, multiple, smaller than primary RCC

— Known primary history is the key history clue

— XGP mimics RCC: large mass, weight loss, anemia; often with staghorn calculus and recurrent infections

— Diagnosis often made at nephrectomy

Simple renal cyst (Bosniak I):

Complex cysts (Bosniak II-IV): see chunk 4 — risk stratified by septations, wall thickening, and enhancement

Angiomyolipoma (AML):

Oncocytoma:

Urothelial carcinoma of the renal pelvis:

Renal lymphoma:

Renal metastasis:

Renal abscess / xanthogranulomatous pyelonephritis (XGP):

Wilms tumor: pediatric, peak age 3-4

Renal sarcoma: rare, aggressive

Board pearl: Fat on CT = AML, not RCC. A renal mass with macroscopic fat (HU <-10) is essentially pathognomonic for angiomyolipoma, except in rare cases of RCC engulfing perirenal fat.

Key distinction: Central, urothelium-based infiltrative lesion with filling defect → urothelial carcinoma (nephroureterectomy). Peripheral, parenchymal, enhancing mass → RCC (partial or radical nephrectomy).

Key Differentials — Other-Category Causes

— Urolithiasis — colicky pain, microscopic hematuria, stones on noncontrast CT

— Urinary tract infection — dysuria, pyuria, leukocyte esterase positive

— Bladder cancer — painless gross hematuria in older smoker; cystoscopy is mandatory in any adult >35 with unexplained hematuria

— Glomerulonephritis — dysmorphic RBCs, RBC casts, proteinuria, hypertension; think IgA, post-strep, ANCA-associated

— Renal infarction — sudden flank pain, LDH elevation, AFib or hypercoagulable state

— Papillary necrosis — diabetes, sickle cell, analgesic abuse, pyelonephritis

— Hydronephrosis from ureteral obstruction

— Polycystic kidney disease — bilateral large kidneys, family history, hypertension, berry aneurysms

— Retroperitoneal sarcoma or lymphoma

— Adrenal mass (pheo, adrenocortical carcinoma)

— Hypercalcemia: multiple myeloma, breast/lung cancer with bone mets, sarcoidosis, hyperparathyroidism

— Erythrocytosis: polycythemia vera (JAK2+), hepatocellular carcinoma, hemangioblastoma, chronic hypoxia (COPD, OSA)

— Stauffer-like LFTs: hepatic mets, primary hepatobiliary disease, drug-induced liver injury

— Multiple myeloma (M-protein, anemia, hypercalcemia)

— Breast/thyroid/lung mets

— Primary bone sarcoma

Mimics of RCC presentation outside renal masses:

Hematuria without mass:

Flank mass without RCC:

Paraneoplastic mimics:

Constitutional symptoms mimics: TB, endocarditis, lymphoma, occult malignancy elsewhere

Left varicocele differentials: primary varicocele (decompresses supine), retroperitoneal mass (lymphoma, RCC), nutcracker syndrome (SMA compressing left renal vein)

Bone pain with lytic lesions:

Step 3 management: Adult >35 with painless gross hematuria → workup must include cystoscopy AND upper-tract imaging (CT urography) to evaluate both bladder and renal/ureteral sources — do not stop at urinalysis.

Board pearl: A young woman with left flank pain + hematuria + intermittent orthostatic proteinuria → nutcracker syndrome (left renal vein compression between aorta and SMA), not RCC; confirm with Doppler US or CT venography.

Secondary Prevention, Discharge Plan, and Long-Term Management

— Discharge medications: analgesia (multimodal — acetaminophen, short-course opioid, avoid NSAIDs early), bowel regimen, VTE prophylaxis (extended in some cases for 4 weeks post-op)

— Wound care, activity restrictions, return precautions (fever, abdominal distention, urinary changes)

— Schedule urology follow-up in 2-4 weeks with basic metabolic panel to assess GFR

— Pembrolizumab for 1 year is FDA-approved for intermediate-high to high-risk resected clear cell RCC (T2 grade 4 or sarcomatoid, T3, T4, N+, or M1-no evidence of disease post-metastasectomy)

— Discuss DFS benefit vs irAE risk in shared decision-making

— Stage I: H&P + labs + chest imaging annually; abdominal imaging at 12 months then as indicated, up to 5 years

— Stage II-III: H&P + labs every 3-6 months for 3 years, then annually; CT chest/abdomen/pelvis every 3-6 months for 3 years, then annually through year 5

— Continue at least every 1-2 years thereafter due to late recurrence risk

— Post-nephrectomy CKD increases CV mortality — manage BP (<130/80), lipids (statin if indicated), diabetes

— ACEi/ARB for proteinuria

— Avoid nephrotoxins (NSAIDs, IV contrast when possible)

— Annual UA and BMP for proteinuria and creatinine

— Smoking cessation — strongest modifiable risk factor; offer counseling + pharmacotherapy (varenicline, NRT, bupropion)

— Weight management, BP control, healthy diet

— Limit nephrotoxic exposures

Post-nephrectomy discharge planning:

Adjuvant therapy:

Surveillance after curative resection (NCCN-based):

Cardiovascular and renal risk reduction:

Lifestyle counseling:

Vaccinations: Influenza, pneumococcal, COVID, RSV (age-eligible); avoid live vaccines while on ICIs

Step 3 management: A patient 3 years post-radical nephrectomy for pT3a clear cell RCC with rising creatinine — start ACE inhibitor if proteinuric, reinforce BP target, ensure annual CT chest/abdomen continues, avoid NSAIDs.

Board pearl: RCC recurrences can occur >10 years after nephrectomy — surveillance does not end at 5 years; lifelong annual clinical assessment is appropriate.

Follow-Up, Monitoring, and Counseling

— TKIs: BP (home monitoring), CBC, CMP, TSH every 4-12 weeks; urinalysis for proteinuria; ECG for QT in cabozantinib/sunitinib

— ICIs: CBC, CMP, LFTs, TSH, glucose, lipase before each cycle; cortisol if symptoms; troponin/BNP if cardiac concern

— Imaging restaging every 8-12 weeks to assess response (RECIST criteria); be aware of pseudoprogression with ICIs — early growth that later regresses

— Cross-sectional imaging every 3-6 months for the first 2 years, then annually

— Watch for growth rate >5 mm/year or change in enhancement → trigger intervention

— ECOG/Karnofsky performance status at each visit

— PROs (patient-reported outcomes): fatigue, pain, GI symptoms, mood

— Screen for depression/anxiety; consider psycho-oncology referral

— Post-nephrectomy: early ambulation, pulmonary toilet, progressive activity over 4-6 weeks

— Bone metastasis with fracture risk: physical therapy, weight-bearing precautions, prophylactic fixation if indicated

— Cancer survivorship program engagement

— Hereditary risk and family screening — refer for genetic counseling if criteria met

— Fertility preservation — discuss before systemic therapy in younger patients

— Contraception — required during TKI/ICI therapy and for several months after (teratogenicity)

— Sun protection — TKIs cause photosensitivity

— Symptom reporting: any fever ≥100.4°F, severe diarrhea, dyspnea, or jaundice on ICI requires urgent contact

— Oral TKIs: pill box, calendar reminders, oncology pharmacy follow-up

— Cost barriers: financial counseling, patient assistance programs

Monitoring parameters during systemic therapy:

Surveillance after ablation or active surveillance:

Functional and quality-of-life monitoring:

Rehabilitation:

Counseling topics:

Adherence support:

Step 3 management: A patient on pembrolizumab develops TSH 0.05 then later TSH 35 with fatigue — diagnose ICI-induced thyroiditis transitioning to hypothyroidism; start levothyroxine, continue ICI, monitor monthly until stable.

Board pearl: Always check baseline TSH and morning cortisol before starting an ICI — undiagnosed hypothyroidism or adrenal insufficiency can be catastrophic if missed and attributed later to drug.

Ethical, Legal, and Patient Safety Considerations

— Must include CKD risk, possible need to extend partial to radical, IVC thrombectomy risk if applicable, transfusion, VTE, mortality

— Document patient's understanding of long-term renal function implications — CKD is a permanent comorbidity

— Discuss alternatives: active surveillance, ablation, observation in frail patients

— Active surveillance vs surgery in small renal masses requires explicit conversation about life expectancy, competing risks, and patient values

— Use validated frailty tools (Clinical Frailty Scale, Geriatric 8) — surgery in patients with limited life expectancy can be harmful rather than helpful

— Ethically and legally, radiologists must communicate, and ordering physicians must act on, incidentally discovered renal masses

— System-level safety: ensure closed-loop follow-up via EHR alerts and patient notification — failure to follow up incidentalomas is a leading malpractice claim

— Younger patients (<46), bilateral/multifocal disease, syndromic features → recommend genetic counseling

— Discuss GINA protections (employment, health insurance) — but not life, disability, long-term care

— Cascade testing of first-degree relatives requires patient consent to share information

— Particularly relevant for non-clear cell, refractory, or rare histologies

— Ensure understanding of trial vs standard-of-care therapy, randomization, and right to withdraw

— Early palliative care referral in metastatic disease improves quality of life and may extend survival

— Advance directives, code status, DNR/DNI conversations

— Hospice eligibility when life expectancy <6 months and curative options exhausted

— Discharge after nephrectomy with incomplete medication reconciliation (NSAIDs, ACEi dose, anticoagulation) — high readmission risk

— Ensure follow-up imaging and labs are scheduled before discharge, with a named oncologist or urologist responsible

Informed consent for nephrectomy:

Shared decision-making in older/frail patients:

Incidental findings (incidentalomas):

Genetic testing considerations:

Clinical trial enrollment:

End-of-life care:

Transition-of-care risks:

Mandatory reporting: Not directly triggered by RCC, but suspected abuse/neglect in dependent adults during home care, or driving impairment from brain mets, may require state-specific reporting.

Step 3 management: A patient with metastatic RCC asks to stop systemic therapy and pursue comfort care; assess decision-making capacity, ensure understanding of prognosis, document discussion, refer to hospice — respect autonomy.

High-Yield Associations and Rapid-Fire Clinical Facts

— Clear cell RCC → VHL gene (3p25) loss

— Type 1 papillary → MET gene mutation

— Type 2 papillary → fumarate hydratase (FH) — HLRCC

— Chromophobe → FLCN — Birt-Hogg-Dubé

— Translocation RCC → TFE3/Xp11.2 in young patients

— Erythrocytosis (EPO), hypercalcemia (PTHrP), hypertension (renin), Stauffer syndrome (cytokines), polymyalgia, AA amyloidosis, cachexia

— Macroscopic fat → AML, not RCC

— Central stellate scar → oncocytoma (but mimics chromophobe)

— Filling defect in collecting system → urothelial carcinoma

— Bilateral infiltrative masses → lymphoma or metastases

Genetics and syndromes:

Paraneoplastic syndromes (memorize):

Imaging features:

Metastatic patterns: lung > bone > liver > brain > adrenal; hypervascular hemorrhagic mets are characteristic

Therapy by IMDC risk: Favorable → ICI-TKI doublet; intermediate/poor → ipi + nivo or ICI-TKI

Cytoreductive nephrectomy: Selected good-PS, low-volume metastatic patients only (post-CARMENA)

Adjuvant pembrolizumab: FDA-approved for intermediate-high-risk resected clear cell RCC

RCC is chemo- and radiation-resistant: radiation reserved for palliation (bone, brain, spinal cord)

Smoking cessation is the single most effective primary and secondary prevention measure

Bosniak III/IV cysts: surgical resection

Renal medullary carcinoma: sickle cell trait + aggressive infiltrative renal mass in young Black patient

Right-sided varicocele: always pathologic; image the abdomen

Wunderlich syndrome: spontaneous perinephric hemorrhage from RCC or AML — emergent embolization

3 cm rule for VHL-associated tumors

Late recurrences (>10 years) characteristic — lifelong surveillance

CKD prevention: prefer partial over radical nephrectomy whenever feasible

Hereditary screening triggers: age <46, bilateral/multifocal, syndromic features, family history

Belzutifan: HIF-2α inhibitor for VHL-RCC and refractory clear cell RCC

Sunitinib hypothyroidism: check TSH every 3 months

Board pearl: When a stem mentions fever, weight loss, hypercalcemia, and a flank mass — RCC with paraneoplastic syndrome is the answer, not lymphoma, not infection.

Board Question Stem Patterns

— "55-year-old man presents after MVC; CT abdomen shows a 3.5 cm enhancing left renal mass." → Next step: dedicated multiphase CT or MRI, urology referral, then partial nephrectomy.

— "60-year-old smoker with weight loss, Hgb 19, and a 7 cm right renal mass." → Diagnosis: RCC with EPO-mediated erythrocytosis; next step: staging chest CT and surgical resection.

— "Patient with new lower extremity edema, ascites, and 8 cm renal mass." → Order MRI to define IVC thrombus level; involve vascular/cardiothoracic surgery.

— Bilateral multifocal clear cell RCC + retinal hemangioblastoma → VHL

— Pneumothorax + facial papules + chromophobe RCC → Birt-Hogg-Dubé

— Cutaneous and uterine leiomyomas + aggressive papillary RCC → HLRCC — operate early

— Patient on nivolumab/ipilimumab with new diarrhea → hold drug, start high-dose corticosteroids

— Patient on pembrolizumab with hypotension, hyponatremia → suspect hypophysitis with secondary adrenal insufficiency; check cortisol/ACTH, give stress-dose hydrocortisone

— New HTN on sunitinib → add antihypertensive, don't stop drug

— Seizure + headache on cabozantinib → PRES, hold drug, image brain

— Patient 4 years post-nephrectomy for T3 RCC with new cough → CT chest to evaluate for pulmonary metastases

— 84-year-old with dementia, CHF, and a 2 cm enhancing renal mass → active surveillance is most appropriate, not surgery

— Sudden severe flank pain, hypotension, Grey-Turner sign, known renal mass → emergent CT angiography and arterial embolization

— Right-sided varicocele or left varicocele not decompressing supine in older man → abdominal imaging for RCC

— Young Black patient with hematuria and central infiltrative renal mass → renal medullary carcinoma

— Resected pT3 grade 4 clear cell RCC with negative margins → offer adjuvant pembrolizumab × 1 year

Classic incidentaloma stem:

Paraneoplastic stem:

IVC thrombus stem:

Hereditary syndrome stems:

ICI toxicity stems:

TKI complication stems:

Surveillance stem:

Active surveillance stem:

Wunderlich stem:

Varicocele stem:

Sickle cell trait stem:

Adjuvant therapy stem:

Board pearl: When the stem describes any combination of constitutional symptoms + flank/hematuria + abnormal labs (Ca, Hgb, alk phos), default to RCC with paraneoplastic syndrome rather than infectious or hematologic diagnoses.

One-Line Recap

Renal cell carcinoma is most often discovered incidentally as a solid enhancing renal mass on cross-sectional imaging in adults, managed by partial or radical nephrectomy for localized disease and by IMDC-risk-stratified immune checkpoint inhibitor + VEGF TKI combinations for metastatic disease, with lifelong surveillance for characteristically late recurrences and proactive recognition of paraneoplastic syndromes, hereditary cancer predisposition, and treatment-related toxicities.

Diagnosis: Multiphase contrast CT (or MRI) is the imaging modality of choice; biopsy is reserved for ablation candidates, suspected metastasis to kidney, or unresectable disease; macroscopic fat = AML, not RCC.

Localized disease: Partial nephrectomy preferred when feasible (preserves GFR, reduces CV mortality); radical nephrectomy for larger/central tumors or IVC thrombus; adjuvant pembrolizumab for high-risk resected clear cell RCC.

Metastatic disease: IMDC risk stratification guides first-line therapy — ICI-TKI doublet or ipilimumab + nivolumab; cytoreductive nephrectomy in selected good-PS patients only; cabozantinib/nivolumab favored for non-clear cell.

Step 3 management essentials: Lifelong surveillance for late recurrence; aggressively manage TKI hypertension and recognize ICI immune-related adverse events early with high-dose corticosteroids; refer for genetic counseling when hereditary features are present; smoking cessation is the single highest-yield modifiable prevention measure for the patient and family alike.

Board pearl: The triad of flank pain, hematuria, and palpable mass is a late-disease finding — modern Step 3 stems present RCC as an incidentaloma or as paraneoplastic syndromes (erythrocytosis, hypercalcemia, Stauffer); recognize them and you've solved the question.