A 55-year-old woman has severe anemia, reticulocytopenia, and a pure red cell aplasia pattern on marrow examination. CT chest shows an anterior mediastinal mass. Which laboratory finding would most strongly support the expected association?

• A Positive direct antiglobulin (Coombs) test
• B High erythropoietin level with absent erythroid precursors ✓
• C Elevated anti-parvovirus B19 IgM titers
• D Monoclonal gammopathy on serum protein electrophoresis

Explanation

Thymoma is a classic cause of acquired pure red cell aplasia. Renal oxygen sensing drives erythropoietin production very high when red cells are lost, yet the marrow shows selective absence of erythroid precursors, a striking mismatch that confirms peripheral destruction plus central failure. Parvovirus C19 causes transient aplastic crisis, not a persistent PRCA with a mediastinal mass.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.