Blood & Lymphoreticular

Myelodysplastic syndromes: risk stratification and management

Clinical Overview and When to Suspect MDS

— Median age at diagnosis ~71; rare under 50 unless therapy-related

— Incidence ~4/100,000 overall, rising to >20/100,000 in patients ≥70

— Male predominance; higher risk in smokers, benzene/solvent exposure, prior alkylators or radiation

— Older adult with unexplained macrocytic anemia after B12/folate/TSH/reticulocyte/copper workup is negative

— Persistent (>6 months) bi- or pancytopenia without obvious cause

— Transfusion-dependent anemia in an elderly patient

— New cytopenia after chemotherapy/radiation (suspect therapy-related MDS, typically 5–7 yrs post-alkylator, 1–3 yrs post-topoisomerase II inhibitor)

— Incidentally noted dysplastic features on smear (hypogranular neutrophils, pseudo–Pelger-Huët cells, Howell-Jolly-like inclusions)

— Fatigue and exertional dyspnea from anemia

— Easy bruising or petechiae from thrombocytopenia

— Recurrent infections from functional neutropenia even with normal counts

— Acquired somatic mutations (SF3B1, TET2, ASXL1, SRSF2, DNMT3A, TP53) drive clonal expansion

— Ineffective hematopoiesis → cytopenias despite cellular marrow (intramedullary apoptosis)

— Risk of AML transformation correlates with blast %, cytogenetics, and mutations

Board pearl: In an elderly patient with unexplained macrocytic anemia + normal B12/folate/TSH + low reticulocyte count, MDS belongs at the top of your differential — order a peripheral smear and refer for bone marrow biopsy rather than empirically treating.

Definition: Myelodysplastic syndromes (MDS) are clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis, peripheral cytopenias despite a normo- or hypercellular marrow, morphologic dysplasia in ≥1 lineage, and a variable risk of progression to acute myeloid leukemia (AML).

Epidemiology:

When to suspect on Step 3:

Common ambulatory presentation:

Pathophysiology essentials:

Presentation Patterns and Key History

— Anemia (~80% at diagnosis): fatigue, dyspnea on exertion, pallor, angina in CAD patients, worsening heart failure, falls

— Thrombocytopenia (~30–40%): mucocutaneous bleeding, epistaxis, gum bleeding, petechiae, menorrhagia

— Neutropenia (~40%): recurrent sinopulmonary infections, oral ulcers, perirectal abscess, cellulitis

— Insidious — symptoms often present months to years before diagnosis

— Slowly worsening transfusion requirement is a hallmark in lower-risk disease

— Abrupt worsening of cytopenias or new circulating blasts suggests progression to AML

— Prior chemotherapy (especially alkylators: cyclophosphamide, melphalan, busulfan; topoisomerase II: etoposide) or radiation → therapy-related MDS (t-MDS), often with del(5q), -7, or complex karyotype and worse prognosis

— Occupational/environmental: benzene, petroleum products, pesticides, tobacco

— Family history: inherited bone marrow failure (Fanconi anemia, dyskeratosis congenita, GATA2, DDX41, RUNX1, SAMD9/9L) — especially if younger patient or family clustering of cytopenias/AML

— Autoimmune disease (RA, relapsing polychondritis, Sweet syndrome, vasculitis) — can coexist with VEXAS syndrome (UBA1 mutation in older men)

— Number/frequency of pRBC transfusions guides iron overload risk (>20–25 units cumulative)

— Document baseline ferritin and prior chelation

— Exclude reversible causes: methotrexate, trimethoprim, hydroxyurea, mycophenolate, valproate, alcohol, copper-chelating zinc supplements

Step 3 management: Before ordering a bone marrow biopsy, always document a thorough medication, toxin, nutritional, and autoimmune review plus HIV testing — many MDS mimics are reversible and a marrow procedure can be deferred if a clear alternative is found.

Symptom triad driven by cytopenias (any combination):

Tempo of illness:

Critical history elements on Step 3:

Transfusion history:

Medication review:

Physical Exam Findings (and Hemodynamic Assessment)

— Pallor of conjunctivae, palmar creases, nail beds

— Fatigue, frailty assessment (gait speed, grip strength) — relevant for transplant eligibility

— Performance status (ECOG/Karnofsky) drives therapy decisions

— Resting and orthostatic vitals; tachycardia and wide pulse pressure with severe anemia

— Flow murmur (systolic ejection) at LUSB

— Signs of high-output failure or decompensated CAD/HF if Hb <7–8

— Use symptom-based rather than purely numeric transfusion thresholds in chronic anemia

— Petechiae (ankles, palate), wet purpura (oral blood blisters → high-risk bleeding sign)

— Ecchymoses; retinal hemorrhages on funduscopy when platelets <10–20k

— Oral mucosa for ulcers, candidiasis

— Perianal/perirectal exam (avoid DRE if neutropenic — risk of bacteremia)

— Skin: cellulitis, IV-line sites, Sweet syndrome (tender erythematous plaques — associated with MDS)

— Splenomegaly is uncommon in pure MDS — its presence suggests MDS/MPN overlap (CMML, atypical CML) or myelofibrosis

— Lymphadenopathy is not a feature of MDS; if present, reconsider diagnosis (lymphoma, CMML)

— Skin hyperpigmentation, hepatomegaly, signs of cardiomyopathy, diabetes, hypogonadism

— Glossitis, peripheral neuropathy → B12 deficiency

— Jaundice, splenomegaly → hemolysis

— Lymphadenopathy → lymphoproliferative disorder

Key distinction: Splenomegaly + monocytosis (>1 ×10⁹/L and ≥10% of WBC) points to chronic myelomonocytic leukemia (CMML), an MDS/MPN overlap — not classic MDS. This changes WHO classification, prognostic tools (CPSS-Mol), and therapy (hypomethylating agents remain first-line; consider hydroxyurea for proliferative CMML).

General appearance:

Hemodynamic assessment of anemia:

Bleeding/thrombocytopenia exam:

Infection screen (neutropenia):

Organomegaly:

Iron overload stigmata (in chronically transfused):

Findings suggesting alternative diagnosis:

Diagnostic Workup — Initial Labs, Smear, and Biomarkers

— Anemia (often macrocytic, MCV 100–110), low/inappropriately normal reticulocyte index

— Thrombocytopenia and/or neutropenia in varying combinations

— Monocytosis raises suspicion for CMML

— Pseudo–Pelger-Huët cells (bilobed/hypolobated neutrophils)

— Hypogranular neutrophils

— Oval macrocytes, basophilic stippling, teardrops, dimorphic RBCs

— Giant or hypogranular platelets

— Circulating blasts (quantify — defines MDS-EB and AML thresholds)

— Vitamin B12, folate, copper, zinc

— TSH, ferritin/iron studies

— LDH, haptoglobin, indirect bilirubin, DAT (rule out hemolysis)

— HIV, hepatitis B/C

— Renal/hepatic panel, EPO level (helps therapy selection)

— ANA, RF if autoimmune cytopenia suspected

— Draw before transfusion ideally

— <500 mU/mL predicts response to ESAs in lower-risk MDS

— Baseline to plan chelation in transfusion-dependent disease

— Not routinely diagnostic; CT only if lymphadenopathy/splenomegaly/infection workup

— Cardiac MRI T2* if iron overload with elevated ferritin (>1000) and many transfusions

— Baseline before therapy in older patients; required before allogeneic transplant

Board pearl: Always check B12, folate, copper, TSH, HIV, and a reticulocyte count before sending an elderly patient with macrocytic anemia for bone marrow biopsy — copper deficiency (post–bariatric surgery, excess zinc/denture cream) can perfectly mimic MDS morphologically and is fully reversible with copper repletion.

CBC with differential and reticulocyte count:

Peripheral blood smear — high-yield dysplastic findings:

Mandatory exclusion labs (rule out reversible mimics) before marrow:

Serum erythropoietin (EPO):

Iron studies and ferritin:

Pregnancy test in reproductive-age women before marrow biopsy/contrast/therapy

Imaging:

ECG/echo:

Diagnostic Workup — Confirmatory Bone Marrow and Cytogenetics

— Usually normo- or hypercellular marrow despite peripheral cytopenias (ineffective hematopoiesis)

— Hypocellular MDS exists (~10–15%) — overlaps with aplastic anemia; PNH flow and telomere length help distinguish

— Quantify blasts (key prognostic threshold):

— <5% blasts → low-blast MDS

— 5–9% → MDS-IB1

— 10–19% → MDS-IB2

— ≥20% blasts in marrow or blood → AML (or AML-equivalent if defining genetics)

— Dysplasia in ≥10% of cells in ≥1 lineage required

— Ring sideroblasts on Prussian blue stain → MDS with low blasts and SF3B1 mutation (favorable, responsive to luspatercept)

— Required for IPSS-R/IPSS-M risk stratification

— Favorable: normal, isolated del(5q), -Y, del(20q)

— Intermediate: +8, del(7q), others

— Poor: -7, inv(3), complex (3 abnormalities)

— Very poor: complex (>3 abnormalities), often with TP53

— SF3B1 → favorable, ring sideroblasts

— TP53 (especially multi-hit/biallelic) → very poor prognosis, AML risk, poor response to HMAs and transplant

— ASXL1, EZH2, RUNX1, SRSF2, U2AF1 → adverse

— DDX41 germline → screen family; affects donor selection

— Aberrant antigen expression; PNH clone (LAIR, FLAER on granulocytes)

— Early if transplant-eligible (age <70–75, fit, higher-risk disease)

Step 3 management: Diagnosis requires the triad of persistent cytopenia + morphologic dysplasia (or MDS-defining cytogenetics/molecular lesion) + exclusion of other causes — and you must complete karyotype plus NGS before assigning a risk score that drives therapy.

Bone marrow aspirate and biopsy (required for diagnosis):

Cytogenetics (conventional karyotype ± FISH):

Molecular/NGS panel (now standard, drives IPSS-M):

Flow cytometry:

HLA typing:

Risk Stratification and First-Line Management Logic

— Cytogenetic risk group (very good → very poor)

— Marrow blast %

— Hemoglobin

— Platelets

— Absolute neutrophil count

— Very low (≤1.5): ~8.8 yr

— Low (>1.5–3): ~5.3 yr

— Intermediate (>3–4.5): ~3 yr

— High (>4.5–6): ~1.6 yr

— Very high (>6): ~0.8 yr

— Lower-risk MDS (IPSS-R Very low/Low/Intermediate ≤3.5): goals are improve cytopenias and quality of life, reduce transfusion burden

— Higher-risk MDS (IPSS-R Int >3.5/High/Very high): goals are alter natural history, prevent AML, pursue cure via allogeneic HSCT if eligible

— Age, ECOG performance status, comorbidities (HCT-CI)

— Transfusion dependence (independent adverse prognostic factor)

— Frailty assessment for transplant decision

— Lower-risk + symptomatic anemia + EPO <500 + low transfusion need → ESA ± G-CSF

— Lower-risk + del(5q) → lenalidomide

— Lower-risk + SF3B1/ring sideroblasts, ESA failure → luspatercept

— Higher-risk + transplant-eligible → HMA bridge → allogeneic HSCT

— Higher-risk + transplant-ineligible → azacitidine ± venetoclax (trials)

Board pearl: Allogeneic stem cell transplant is the only curative therapy for MDS — every newly diagnosed patient under ~75 with adequate fitness deserves an early transplant evaluation and HLA typing, especially if higher-risk by IPSS-R/IPSS-M.

IPSS-R (Revised International Prognostic Scoring System) — the Step 3 workhorse. Five variables:

IPSS-R categories and median survival:

IPSS-M integrates molecular mutations (especially TP53, SF3B1, ASXL1); reclassifies ~50% of patients vs IPSS-R and is now preferred where available.

Practical 2-bucket framework for therapy:

Patient-side modifiers:

Initial decision tree:

Pharmacotherapy — First-Line Regimens

— Erythropoiesis-stimulating agents (epoetin alfa, darbepoetin):

— First-line if symptomatic anemia and serum EPO <500 mU/mL, low transfusion burden (<4 U/8 wk)

— Add G-CSF if ring sideroblasts and inadequate response

— Response rate ~40–60%; monitor Hb (target 10–12, avoid >12 — thrombosis/HTN risk)

— Luspatercept (TGF-β superfamily ligand trap):

— Now first-line for SF3B1-mutated/ring sideroblast lower-risk MDS (COMMANDS trial) and after ESA failure

— SC every 3 weeks; monitor BP, watch for fatigue, bone pain

— Lenalidomide:

— Indicated for del(5q) lower-risk MDS, transfusion-dependent

— Transfusion independence ~60–70%

— AEs: cytopenias, teratogenicity (REMS program), VTE — consider aspirin

— Immunosuppression (ATG + cyclosporine): select hypocellular MDS, younger patients, HLA-DR15+

— Hypomethylating agents (HMAs):

— Azacitidine 75 mg/m² SC × 7 days every 28 days — only agent shown to improve OS (AZA-001 trial, ~9-month survival benefit)

— Decitabine alternative; oral decitabine/cedazuridine available

— Requires 4–6 cycles before declaring response — do not stop early for cytopenias

— Continue indefinitely while responding

— Response: ~50% hematologic improvement, ~15–20% CR

— RBC transfusions for symptomatic anemia (not by Hb number alone)

— Platelet transfusions for bleeding or <10k prophylactically

— Antibiotics for febrile neutropenia

— Iron chelation (deferasirox) if ferritin >1000–2500 and >20 RBC units, transplant candidate or lower-risk with long expected survival

Step 3 management: When starting azacitidine, counsel the patient that cytopenias often worsen in cycles 1–2 and response assessment requires at least 4–6 cycles — premature discontinuation is a classic management error tested on the exam.

Lower-risk MDS — anemia-directed therapy:

Higher-risk MDS — disease-modifying:

Supportive care (all patients):

Allogeneic HSCT and Advanced Therapeutics

— Indicated for higher-risk IPSS-R/IPSS-M patients who are fit

— Increasingly offered to lower-risk patients with high-risk molecular features (TP53, complex karyotype) or severe cytopenias

— Age cutoff is biologic, not chronologic — fit patients up to 75 are routinely transplanted with reduced-intensity conditioning (RIC)

— HLA typing of patient and siblings

— Donor search: matched sibling > matched unrelated > haploidentical/cord

— HCT-comorbidity index, cardiac/pulmonary/renal/hepatic workup

— Infectious screen (CMV, EBV, HBV, HCV, HIV, syphilis, strongyloides if exposed)

— Dental clearance, vaccinations updated

— Bridging therapy with HMA to reduce blast burden if ≥10% blasts

— Myeloablative (busulfan/cyclophosphamide, flu/bu4) — younger, fit

— Reduced-intensity (flu/melphalan, flu/bu2) — older or comorbid

— GVHD prophylaxis (tacrolimus/MTX or post-transplant cyclophosphamide)

— Infection prophylaxis (acyclovir, PJP, antifungal)

— Monitor for relapse with chimerism studies and marrow assessments

— Venetoclax + azacitidine — borrowed from AML, active in higher-risk MDS (clinical trials, not yet FDA-approved for MDS specifically)

— Ivosidenib/enasidenib for IDH1/IDH2-mutated MDS

— Imetelstat — telomerase inhibitor for lower-risk, transfusion-dependent post-ESA

— APR-246 (eprenetapopt) for TP53-mutated (investigational)

— Poor HMA response, early relapse post-transplant; clinical trial preferred

CCS pearl: For a higher-risk MDS patient, the correct CCS sequence is diagnose → IPSS-R/M → HLA-type patient and siblings → start azacitidine as a bridge → proceed to allo-HSCT — do not delay transplant referral until after multiple HMA cycles fail.

Allogeneic hematopoietic stem cell transplant (allo-HSCT) — only curative option:

Pre-transplant logistics (CCS-style sequence):

Conditioning regimens:

Post-transplant priorities:

Emerging/second-line agents:

Therapy-related and TP53-mutant MDS:

Special Populations — Elderly and Renal/Hepatic Impairment

— Use geriatric assessment (CGA), not just age, to guide intensity

— Frailty, falls, polypharmacy, cognitive impairment all reduce transplant tolerance

— HCT-CI score ≥3 identifies higher transplant mortality

— Reduced-intensity conditioning extends allo-HSCT eligibility to fit septuagenarians

— Disease-modifying (HMA, transplant) vs best supportive care with transfusions and growth factors

— Many elderly lower-risk patients live for years with transfusion support alone

— Early palliative care integration improves QOL in higher-risk disease

— Lenalidomide: dose-adjust by CrCl (10 mg if CrCl 30–60; 5 mg if <30; 2.5 mg on dialysis)

— Azacitidine: use with caution if Cr >2 or BUN markedly elevated; monitor electrolytes (renal tubular wasting reported)

— Decitabine: limited data in severe renal impairment, no formal adjustment

— Deferasirox: contraindicated if CrCl <40; monitor Cr weekly initially

— ESAs: effective regardless of renal function; especially useful in CKD-associated anemia overlap

— Deferasirox: contraindicated in Child-Pugh C; reduce dose in B

— Azacitidine: caution with severe hepatic disease, contraindicated in advanced hepatic malignancy

— Lenalidomide largely renally cleared — hepatic adjustment minimal

— Liberal threshold (Hb 8–9) reasonable in symptomatic CAD/HF

— Iron overload accumulates faster in low body mass

— Volume overload risk — slow transfusion rates, consider diuretic between units

Board pearl: In a frail 80-year-old with lower-risk MDS, the right answer on the boards is often best supportive care (transfusions, ESAs, G-CSF for infections) and goals-of-care discussion — not aggressive HMA or transplant referral.

Elderly (median MDS patient is >70):

Goals-of-care framework:

Renal impairment:

Hepatic impairment:

Transfusion considerations in elderly:

Special Populations — Pregnancy, Pediatrics, Inherited Syndromes

— Classified separately: refractory cytopenia of childhood (RCC), MDS with excess blasts

— Strong association with inherited bone marrow failure syndromes — always investigate:

— Fanconi anemia (chromosomal breakage testing with DEB/MMC)

— Dyskeratosis congenita (telomere length, TERC/TERT/DKC1 mutations) — triad: nail dystrophy, oral leukoplakia, reticular skin pigmentation

— Shwachman-Diamond (SBDS; pancreatic insufficiency + neutropenia)

— Diamond-Blackfan, GATA2 deficiency, SAMD9/9L

— Monosomy 7 is most common cytogenetic abnormality

— Allo-HSCT is first-line for symptomatic pediatric MDS; HMAs less established

— DDX41, RUNX1, CEBPA, ANKRD26, ETV6, GATA2, TP53 (Li-Fraumeni)

— Screen if: dx <50, family hx of cytopenias/MDS/AML, multiple cancers

— Affects donor selection — avoid related donors with the same germline mutation

— Rare; pregnancy can worsen cytopenias and bleeding risk

— Lenalidomide and HMAs are teratogenic — contraindicated; effective contraception required

— Supportive care (transfusions, careful platelet management for delivery) is mainstay

— Multidisciplinary management with MFM and hematology

— Avoid live vaccines in neutropenic infants of treated mothers

— UBA1 somatic mutation; inflammatory features (chondritis, vasculitis, fever) + MDS-like cytopenias and vacuolated myeloid precursors

— Refractory to standard immunosuppression; HMAs and allo-HSCT considered

Key distinction: A young patient with MDS — especially with family history of cytopenias or AML — should trigger germline testing (DDX41, RUNX1, GATA2, Fanconi breakage, telomere length) before transplant, because using an affected related donor leads to donor-derived disease.

Pediatric MDS (rare, ~4% of childhood hematologic malignancies):

Germline predisposition in adults (increasingly recognized):

Pregnancy and MDS:

VEXAS syndrome (older men):

Complications and Adverse Outcomes

— ~30% of MDS progresses to AML; rate depends on IPSS-R/IPSS-M

— Triggers: rising blasts, new circulating blasts, worsening cytopenias, new cytogenetic abnormalities (clonal evolution)

— Therapy-related and TP53-mutant disease have highest AML risk and worst post-transformation outcomes

— Anemia: worsening cardiac ischemia, decompensated HF, falls, fatigue-driven disability

— Neutropenia: bacterial sepsis (especially gram-negative, Pseudomonas), fungal infections (Aspergillus, Candida), perirectal abscesses

— Thrombocytopenia: intracranial hemorrhage, GI bleed, especially with platelets <10–20k or qualitative platelet dysfunction

— Iron overload: cardiomyopathy (most lethal), cirrhosis, endocrinopathies (diabetes, hypogonadism, hypothyroidism)

— Alloimmunization → difficult crossmatch, refractoriness

— TRALI, TACO, infections (rare)

— Ferritin >1000 in transfused MDS = consider chelation, especially if transplant candidate

— Cytopenias worsening early in therapy (cycles 1–2)

— Injection site reactions (azacitidine SC)

— Nausea, fatigue, infections

— Cumulative myelosuppression with extended use

— Acute and chronic GVHD

— Opportunistic infections (CMV reactivation, PJP, invasive fungal)

— Veno-occlusive disease (sinusoidal obstruction syndrome)

— Relapse — main cause of post-transplant mortality in higher-risk MDS

— Sweet syndrome, pyoderma gangrenosum, vasculitis, AIHA/ITP — may flare with MDS progression

Step 3 management: A transfusion-dependent MDS patient with ferritin >1000 and >20 RBC units who is a transplant candidate or has long expected survival should be started on deferasirox (oral chelator) — monitor renal function, LFTs, and audiologic/ophthalmologic baseline.

Progression to acute myeloid leukemia (AML):

Cytopenia complications:

Transfusion-related complications:

HMA-related toxicity:

Post-transplant complications:

Autoimmune phenomena:

When to Escalate Care — ICU, Consult, Inpatient Triage

— Febrile neutropenia (ANC <500 with fever ≥38.3°C once or ≥38.0°C sustained) — IV broad-spectrum (cefepime or pip-tazo) within 1 hour

— Symptomatic anemia not safely managed outpatient (active angina, syncope, HF decompensation)

— Active bleeding with thrombocytopenia (GI bleed, hematuria, epistaxis requiring packing)

— Suspected transformation to AML with hyperleukocytosis or DIC

— Severe infection with hemodynamic instability

— Septic shock requiring vasopressors

— Respiratory failure (pneumonia in neutropenic host, ARDS)

— Massive hemorrhage with coagulopathy

— Tumor lysis syndrome in transformed disease starting induction

— Vitals q4h, isolation, contact precautions

— Blood cultures ×2 (one peripheral, one from each lumen of any central line)

— Urine culture, CXR, lactate, CBC, CMP, procalcitonin

— Empiric monotherapy: cefepime or piperacillin-tazobactam

— Add vancomycin if hemodynamic instability, skin/soft tissue infection, line infection, or known MRSA colonization

— Add antifungal (voriconazole or echinocandin) if persistent fever >4–7 days

— G-CSF for documented neutropenia if prolonged anticipated

— Hematology — at diagnosis, all changes in counts/therapy

— Transplant center referral — early in higher-risk disease

— Palliative care — for symptom management and goals of care in advanced/transplant-ineligible

— Infectious disease — for atypical infections, fungal disease

— Cardiology — pre-transplant, iron-overload cardiomyopathy

CCS pearl: In a febrile MDS patient with ANC <500, the first orders are blood cultures + IV cefepime within 60 minutes — do not wait for imaging or further labs. Delayed antibiotics is the most commonly missed action on neutropenic fever simulations.

Hospitalize for:

ICU triage criteria:

CCS-style inpatient orders for febrile neutropenia (high-yield):

Specialty consults:

Key Differentials — Other Hematologic Causes of Cytopenia

— Hypocellular marrow (<25%), pancytopenia, no dysplasia, no blasts

— Younger patients more typical; idiopathic or post-hepatitis, drugs, PNH overlap

— Treatment: ATG + cyclosporine, eltrombopag, or allo-HSCT

— Overlap with hypocellular MDS — cytogenetics/molecular help distinguish

— Acquired PIGA mutation, complement-mediated hemolysis, thrombosis, cytopenias

— Flow cytometry for CD55/CD59 deficiency or FLAER negativity

— Small PNH clones common in MDS/aplastic anemia

— ≥20% blasts in marrow or peripheral blood, or defining genetics (t(8;21), inv(16), t(15;17), NPM1)

— Auer rods on smear

— MDS-EB2 (10–19% blasts) sits just below this threshold

— CMML (monocytosis ≥1.0 ×10⁹/L and ≥10%)

— Atypical CML, MDS/MPN with ring sideroblasts and thrombocytosis (SF3B1 + JAK2)

— Splenomegaly, proliferative features

— Splenomegaly, leukoerythroblastic smear, tear-drop cells, JAK2/CALR/MPL

— Marrow fibrosis on reticulin stain

— Cytopenias (often neutropenia), associated with RA

— Clonal CD3+CD8+CD57+ T cells; STAT3 mutations

— Pancytopenia, splenomegaly, dry tap

— BRAF V600E, flow with CD11c/CD25/CD103

— Younger age, less dysplasia, normal karyotype → favors aplastic; respond to IST

Key distinction: Hypocellular marrow + cytopenias + no dysplasia + normal karyotype = aplastic anemia, while hypocellular marrow + dysplasia or MDS-defining cytogenetics (e.g., -7) = hypocellular MDS — both may respond to immunosuppression, but only MDS is a clonal premalignant disorder needing potential transplant.

Aplastic anemia:

Paroxysmal nocturnal hemoglobinuria (PNH):

Acute myeloid leukemia (AML):

Myeloproliferative/MDS overlap (MDS/MPN):

Myelofibrosis:

Large granular lymphocyte (LGL) leukemia:

Hairy cell leukemia and other lymphoproliferative disorders:

Hypoplastic MDS vs aplastic anemia overlap:

Key Differentials — Non-Hematologic and Reversible Mimics

— Vitamin B12 deficiency: macrocytic anemia, hypersegmented neutrophils, neuropathy; check MMA/homocysteine if borderline

— Folate deficiency: macrocytosis without neuropathy

— Copper deficiency: classic MDS mimic — pancytopenia, ringed sideroblasts, vacuolated precursors; from bariatric surgery, excess zinc, denture creams. Fully reversible with copper replacement

— Iron deficiency (microcytic, but coexists with MDS)

— Methotrexate, trimethoprim, hydroxyurea, mycophenolate, valganciclovir, linezolid (>2 wk)

— Alcohol — direct marrow toxicity, dyserythropoiesis, vacuolated precursors

— Chemotherapy effect (recent or ongoing)

— Benzene, lead, arsenic

— HIV — direct marrow suppression and dysplasia; always test

— Parvovirus B19 — pure red cell aplasia, especially in immunocompromised

— Hepatitis B/C, EBV, CMV

— Tuberculosis (miliary) — pancytopenia with marrow granulomas

— Visceral leishmaniasis in endemic exposures

— SLE, Felty syndrome (RA + splenomegaly + neutropenia), Evans syndrome

— LGL leukemia overlap

— VEXAS (UBA1) — older men with cytopenias + inflammation

— Hypothyroidism — macrocytic anemia

— Adrenal insufficiency — normocytic anemia

— Cirrhosis, portal hypertension — pancytopenia from sequestration; marrow is normal

— EPO deficiency anemia; usually normocytic, normal smear

Board pearl: A patient on long-standing denture-cream use or post-bariatric surgery presenting with pancytopenia, neuropathy, and ring sideroblasts has copper deficiency, not MDS — check serum copper and ceruloplasmin before bone marrow biopsy; replacement reverses the picture entirely.

Nutritional deficiencies (always exclude first):

Drug- and toxin-induced cytopenias:

Infections:

Autoimmune cytopenias and rheumatologic:

Endocrine:

Hypersplenism:

Renal failure:

Pregnancy-related dilutional changes

Long-Term Plan, Secondary Prevention, and Discharge Medications

— Continue ESA ± G-CSF with Hb target 10–12 (avoid >12 to limit thrombosis)

— Luspatercept q3 weeks for SF3B1/ring sideroblast disease

— Lenalidomide maintenance for del(5q) responders; monitor for cytopenias and secondary AML risk

— Transfuse based on symptoms, not absolute Hb threshold, in chronic disease

— Iron chelation (deferasirox) if ferritin persistently >1000–2500 and high transfusion burden

— Azacitidine continued indefinitely while responding (do not stop after CR)

— Post-allo-HSCT: immunosuppression taper, GVHD surveillance, chimerism, azacitidine maintenance for high-risk molecular features in select patients

— Annual inactivated influenza vaccine

— Pneumococcal (PCV20 or PCV15 + PPSV23)

— RSV vaccine if ≥60

— Recombinant zoster (Shingrix) — safe in MDS; avoid live zoster vaccine

— COVID-19 boosters per current guidance

— Hepatitis B vaccination (especially pre-transplant); avoid live vaccines around transplant

— PJP prophylaxis (TMP-SMX) and antiviral prophylaxis during HMA/transplant per protocol

— Aggressive control of HTN, diabetes, dyslipidemia — cardiac comorbidity drives mortality

— Bone density and vitamin D, especially post-transplant on steroids

— Increased risk of solid tumors, especially in t-MDS — maintain age-appropriate USPSTF screening

— Skin exams post-transplant (squamous cell, melanoma risk)

— Smoking cessation, alcohol limitation, occupational exposure mitigation

Step 3 management: In a chronically transfused MDS patient discharged after a hospitalization, your medication reconciliation should include deferasirox (if ferritin >1000 and ongoing transfusions), folate supplementation, PJP prophylaxis during HMA therapy, and updated non-live vaccinations — these are commonly missed transition-of-care items.

Lower-risk MDS — ambulatory longitudinal plan:

Higher-risk MDS — disease-modifying maintenance:

Infection prevention:

Cardiovascular and bone health:

Cancer surveillance:

Lifestyle counseling:

Follow-Up, Monitoring, and Counseling

— CBC every 4–12 weeks depending on stability and therapy

— Reticulocyte count, iron studies, ferritin every 3 months if transfusion-dependent

— Bone marrow re-evaluation if unexplained worsening cytopenias, new blasts on smear, or change in transfusion needs — not on a fixed schedule

— CBC weekly during induction, then before each cycle

— CMP each cycle; LFTs and renal function

— Assess response after 4–6 cycles (IWG criteria) — do not abandon early

— Marrow re-evaluation at 6 cycles or for suspected progression

— Chimerism studies at 30, 60, 100 days, then periodically

— Disease-specific monitoring (MRD by flow/NGS) every 3 months × 2 years

— GVHD assessment at each visit; CMV PCR weekly early post-transplant

— Vaccination restart at ~6–12 months (inactivated) and 24 months (live, if no GVHD/immunosuppression)

— Ferritin every 3 months

— Cardiac and hepatic T2\* MRI if >20 units transfused or ferritin >1000 sustained

— Endocrine screening (HbA1c, TSH, gonadal axis) in long-term transfusion patients

— Bleeding precautions (avoid NSAIDs, contact sports if thrombocytopenic; soft toothbrush)

— Infection precautions (hand hygiene, food safety, when to call: fever ≥38.0°C)

— Transfusion logistics, premedications, expected QOL improvements

— Disease trajectory: lower-risk often stable for years; higher-risk requires earlier transplant discussion

— Advance care planning, especially in higher-risk and transplant-ineligible

Board pearl: Treatment response on hypomethylating agents requires 4–6 full cycles — counsel patients up front that worsening counts early in therapy do not mean failure, and that premature discontinuation is the most common avoidable reason for "non-response."

Lower-risk MDS, stable:

On HMA therapy:

Post–allo-HSCT:

Iron overload monitoring:

Patient counseling priorities:

Ethical, Legal, and Patient Safety Considerations

— Allo-HSCT carries ~15–30% non-relapse mortality; consent must include realistic discussion of GVHD, infection, infertility, secondary malignancy

— Use teach-back and consider decision aids; document goals-of-care preferences

— Older or frail patients need explicit comparison of HMA-only vs transplant survival and QOL trajectories

— Higher-risk MDS in a frail elderly patient often warrants early palliative care referral

— Discuss transfusion-only supportive care as a legitimate, dignity-preserving option

— Address code status, DNR/DNI, surrogate decision-maker, healthcare proxy at diagnosis and again before each escalation

— Discovery of DDX41, RUNX1, GATA2, TP53 germline mutations has implications for relatives — offer genetic counseling and cascade testing

— Avoid using related donor with same germline variant — critical patient safety issue

— Insurance/employment discrimination concerns (GINA protects most, but not life/disability insurance)

— Patients on HMA cycles + neutropenia are at high risk for febrile neutropenia between visits — ensure clear instructions on fever threshold (≥38.0°C), 24/7 contact number, and written action plan at discharge

— Med-rec at every transition: deferasirox dosing, antimicrobial prophylaxis, growth-factor schedule, transfusion appointments

— Reconcile across oncology, primary care, and transplant teams

— MDS is reportable to state cancer registries (provider responsibility)

— Therapy-related MDS may prompt review of prior chemotherapy practices but is not individually reportable as adverse event

— Many novel agents (venetoclax + HMA, imetelstat, IDH inhibitors) are trial-based — ensure equitable referral

— Document and address financial toxicity (oral agents like decitabine/cedazuridine, deferasirox)

Step 3 management: When discharging a neutropenic MDS patient mid-HMA cycle, a written neutropenic precautions sheet, after-hours contact, thermometer, and follow-up CBC within 7 days are the safety-net items that prevent the most common transition-of-care failure — delayed presentation of febrile neutropenia.

Informed consent for transplant:

Goals of care and advance directives:

Germline testing ethics:

Transition-of-care safety (high-yield Step 3):

Reporting and registry:

Clinical trial access and equity:

High-Yield Associations and Rapid-Fire Facts

— Isolated del(5q) → "5q- syndrome": older women, macrocytic anemia, normal/high platelets, hypolobated megakaryocytes — responds to lenalidomide

— Monosomy 7 / del(7q) → poor prognosis, common in pediatric and t-MDS

— Complex karyotype (≥3 abnormalities) → very poor, often TP53-driven

— +8 → intermediate; may respond to immunosuppression

— SF3B1 → ring sideroblasts, favorable, luspatercept-responsive

— TP53 (biallelic) → very poor; AML-like behavior; poor HMA response; poor transplant outcomes

— ASXL1, EZH2, RUNX1, U2AF1, SRSF2 → adverse

— DDX41 germline → older male, slow progression, often HMA-responsive; screen relatives

— SF3B1 + JAK2 → MDS/MPN with ring sideroblasts and thrombocytosis

— Sweet syndrome, pyoderma gangrenosum, relapsing polychondritis — paraneoplastic skin/inflammation

— VEXAS (UBA1) — older men, chondritis, vasculitis, vacuolated precursors

— Trisomy 8 MDS — Behçet-like symptoms

— Alkylators → t-MDS at 5–7 years, complex karyotype/-7

— Topoisomerase II inhibitors (etoposide) → t-AML at 1–3 years, 11q23 (MLL/KMT2A) rearrangements (often skips MDS phase)

— Hypogranular neutrophils, pseudo–Pelger-Huët, micromegakaryocytes, ring sideroblasts → dysplastic hallmarks

— Auer rods → reclassify as AML regardless of blast count if defining genetics present

— IPSS-R >3.5 = higher risk → consider HMA + transplant

— EPO <500 predicts ESA response

— Ferritin >1000–2500 + heavy transfusion = chelate

Board pearl: Older woman + macrocytic anemia + normal-to-high platelets + isolated del(5q) = 5q- syndrome → start lenalidomide with VTE prophylaxis and contraception counseling — one of the most testable scenarios in MDS.

Cytogenetic-clinical associations:

Molecular-clinical associations:

Syndromic associations:

Therapy associations:

Lab/morphology pearls:

Risk score thresholds:

Board Question Stem Patterns

— 72-year-old with fatigue, MCV 108, normal B12/folate/TSH, low reticulocytes, smear with hypogranular neutrophils.

— Answer path: bone marrow biopsy + cytogenetics + NGS panel

— 68-year-old woman, transfusion-dependent macrocytic anemia, platelets 450k, marrow shows isolated del(5q).

— Answer: lenalidomide (with contraception counseling and VTE prophylaxis)

— Patient with breast cancer treated with cyclophosphamide 6 years ago, now pancytopenic with complex karyotype and TP53 mutation.

— Answer: discuss prognosis, refer for clinical trial or allo-HSCT (poor HMA response expected)

— On azacitidine cycle 2, ANC 300, T 38.5°C.

— First action: blood cultures and IV cefepime within 1 hour

— Post–gastric-bypass patient on chronic zinc supplements, pancytopenic with ring sideroblasts and neuropathy.

— Answer: serum copper level, replace copper, hold marrow biopsy

— 62-year-old fit man, IPSS-R high, matched sibling available.

— Answer: start azacitidine as bridge → allo-HSCT

— Lower-risk MDS, symptomatic anemia, EPO level 200, transfusion need 2 U/month.

— Answer: start ESA; if SF3B1+/ring sideroblasts and ESA fails → luspatercept

— Transfusion-dependent MDS, 30 RBC units, ferritin 2800, transplant candidate.

— Answer: deferasirox with renal/hepatic monitoring

— Splenomegaly + monocytes 1.8 ×10⁹/L (15% of WBC).

— Answer: CMML, not MDS — use CPSS-Mol, HMAs first-line

— Older man with relapsing polychondritis, fevers, macrocytic anemia, vacuolated marrow precursors.

— Answer: UBA1 mutation testing, hematology referral

Key distinction: "Macrocytic anemia + normal B12/folate" in an elderly patient pivots to bone marrow biopsy with cytogenetics + NGS; "macrocytic anemia + neuropathy + denture cream/zinc" pivots to serum copper — pick your test based on the exposure history.

Classic stem 1 — the macrocytic anemia workup:

Classic stem 2 — 5q- syndrome:

Classic stem 3 — therapy-related MDS:

Classic stem 4 — neutropenic fever in MDS:

Classic stem 5 — copper deficiency mimic:

Classic stem 6 — IPSS-R higher risk, transplant decision:

Classic stem 7 — ESA selection:

Classic stem 8 — iron overload:

Classic stem 9 — CMML mimic:

Classic stem 10 — VEXAS:

One-Line Recap

Myelodysplastic syndromes are clonal stem cell disorders of ineffective hematopoiesis where IPSS-R/IPSS-M risk stratification divides patients into lower-risk disease managed with ESAs, luspatercept, or lenalidomide for symptom control, and higher-risk disease managed with azacitidine bridging to the only curative therapy — allogeneic stem cell transplant in eligible patients.

— Lower-risk → ESA if EPO <500; luspatercept for SF3B1/ring sideroblasts; lenalidomide for isolated del(5q); supportive care with transfusions, growth factors, and iron chelation when ferritin >1000.

— Higher-risk → azacitidine ×4–6 cycles minimum and early HLA typing + allo-HSCT referral in fit patients up to ~75; transplant is the only cure.

Board pearl: Whenever the stem gives you an older adult with unexplained macrocytic anemia, normal B12/folate, and a hypercellular marrow with dysplasia, the engine of the question is almost always MDS — and the next step pivots on IPSS-R risk and transplant eligibility.

Diagnose: Persistent unexplained cytopenia (often macrocytic anemia) + morphologic dysplasia or MDS-defining cytogenetics/molecular lesion + exclusion of reversible mimics (B12, folate, copper, HIV, hypothyroidism, drugs, alcohol) → confirm with bone marrow biopsy + karyotype + NGS panel.

Risk-stratify: Use IPSS-R (cytogenetics, blasts, Hb, platelets, ANC) and increasingly IPSS-M (adds TP53, SF3B1, ASXL1, etc.) to split into lower- vs higher-risk — this single step drives every downstream therapy decision.

Treat by bucket:

Prevent and counsel: Neutropenic-fever education and IV cefepime within 1 hour for ANC <500 with fever; non-live vaccinations (influenza, pneumococcal, RSV, Shingrix); germline testing (DDX41, RUNX1, GATA2) in young or familial cases — avoid related donors carrying the same mutation; integrate palliative care and advance care planning early in transplant-ineligible higher-risk disease.