PA17.1 | Aplastic Anemia & Bone Marrow Failure — Graded Quiz

A 17-year-old girl presents with 6 weeks of progressive fatigue, gum bleeding, and two episodes of epistaxis. She has no lymphadenopathy or organomegaly. CBC: Hb 5.8 g/dL (normocytic), WBC 1.8 × 10⁹/L (neutrophils 0.3 × 10⁹/L), platelets 9 × 10⁹/L, reticulocyte count 0.4%. A bone marrow trephine biopsy is reported as: '10% cellularity with fat replacement; no blasts; no fibrosis; no malignant cells.' Which single criterion in this report is most critical for classifying this as 'very severe aplastic anaemia' (vsAA) rather than 'severe aplastic anaemia' (SAA)?

A 14-year-old boy is evaluated for aplastic anaemia. His physical examination reveals short stature (below 3rd percentile), several café-au-lait spots, and the right thumb appears hypoplastic. A chromosome breakage test using diepoxybutane (DEB) shows significantly increased chromosomal breaks compared to controls. His sister (age 18) has a normal CBC and normal DEB test. Which statement about this patient's condition is most accurate?

A 55-year-old man presents with pancytopenia (Hb 7.2 g/dL, WBC 2.1 × 10⁹/L, platelets 34 × 10⁹/L). He was treated for seronegative hepatitis 3 months ago and remains non-icteric. Bone marrow biopsy: 15% cellularity, predominantly fat cells, markedly reduced trilineage haematopoiesis, no blasts, no dysplastic changes, no fibrosis. Which statement best describes the pathogenesis of aplastic anaemia in this clinical context?

A 23-year-old woman with severe aplastic anaemia (SAA) has no HLA-matched sibling. She receives horse anti-thymocyte globulin (hATG) plus cyclosporine as first-line immunosuppressive therapy. At 6-month follow-up, her CBC shows: Hb 9.1 g/dL, WBC 3.2 × 10⁹/L (neutrophils 1.4 × 10⁹/L), platelets 54 × 10⁹/L. She is no longer transfusion-dependent. However, flow cytometry shows a GPI-anchor-deficient clone comprising 12% of her granulocytes. What is the most accurate interpretation of this finding?

A 65-year-old man presents with pancytopenia: Hb 8.4 g/dL, MCV 98 fL, WBC 2.6 × 10⁹/L, platelets 42 × 10⁹/L. Physical examination shows NO hepatosplenomegaly and NO lymphadenopathy. Bone marrow aspirate shows hypercellular fragments with dysplastic erythroid precursors, hypersegmented neutrophils, and hypolobate megakaryocytes. Marrow blasts are 4%. Which diagnosis is most consistent with this picture?

A 30-year-old female nurse presents with a 3-month history of easy bruising and recurrent upper respiratory infections. CBC: Hb 9.3 g/dL, MCV 88 fL, WBC 2.0 × 10⁹/L (neutrophils 0.6 × 10⁹/L), platelets 28 × 10⁹/L. She reports handling chloramphenicol eye drops regularly at work. Bone marrow biopsy: 20% cellularity with marked fat replacement, no dysplasia, no fibrosis, no blasts. She has NO history of relevant family disease, congenital anomalies, or prior chemotherapy. Which management step is MOST urgent at this moment?

A bone marrow biopsy is reported from a 40-year-old man with pancytopenia. The pathologist describes: 'Marrow cellularity 8%; haematopoietic cells constitute less than 10% of the marrow space; remainder is fat; no fibrosis; no blasts; no abnormal infiltrate. Residual haematopoietic cells include lymphocytes and plasma cells.' How should the marrow cellularity estimate be interpreted in relation to this patient's age?

A 25-year-old man with severe aplastic anaemia (SAA) has an HLA-matched sibling identified. The haematologist plans allogeneic haematopoietic stem cell transplantation (allo-HSCT) as definitive therapy. The family asks why HSCT is preferred over long-term immunosuppressive therapy (IST) in a young patient with a matched donor. Which explanation is most scientifically accurate?

During a bone marrow aspiration procedure for a patient with suspected AA, the clinician withdraws the needle into the syringe and finds the aspirate contains only peripheral blood with no marrow spicules or particles — a 'dry tap.' Which is the most appropriate immediate next step?

A 10-year-old boy presents with recurrent anaemia, short stature, and hypopigmented macules on the trunk. His parents are consanguineous. CBC shows pancytopenia. Karyotype shows an increased frequency of chromatid exchanges in cultured lymphocytes after mitomycin C (MMC) treatment. His older brother (12 years) is healthy, with a normal MMC chromosomal stress test. Which statement regarding the brother as a potential donor for allogeneic HSCT is most accurate?

A 50-year-old woman with newly diagnosed aplastic anaemia has no HLA-matched sibling. Her absolute neutrophil count is 0.42 × 10⁹/L (not very severe AA). She is not a candidate for matched unrelated donor HSCT due to comorbidities. Horse anti-thymocyte globulin (hATG) + cyclosporine is planned. Which statement accurately predicts her expected haematologic response trajectory?

A 19-year-old female college student presents with 6 weeks of pallor, easy bruising, and recurrent mouth ulcers. She was previously healthy and takes no medications. There is NO hepatosplenomegaly and NO lymphadenopathy. CBC: Hb 7.6 g/dL (normocytic), WBC 2.3 × 10⁹/L (ANC 0.45 × 10⁹/L), platelets 18 × 10⁹/L, reticulocyte count 0.3%. Bone marrow trephine: 12% cellularity, predominantly fat, markedly reduced trilineage haematopoiesis, no dysplasia, no blasts, no fibrosis. Which laboratory result would MOST strongly support an immune-mediated (T-cell-driven) pathogenesis in this patient and guide treatment selection?