Vasanti, a 25-year-old-girl, presents with complaints of fever and weakness. On examination there is splenomegaly of 3 cm below the costal margin. Hb is 8 gm/dL, TLC is 3,000/mm3, platelet count is 80,000/mm3. Which of the following is the least likely diagnosis

Answer is C (Aplastic anemia) Patient in question has anemia with pancytopenia and an enlarged spleen. Presence of an enlarged spleen makes aplastic anemia the least likely diagnosis. All other conditions mentioned as options may present with both pancytopenia and splenomegaly. Parameters Normal Patient in question Inference Hb 12-18 g/dl 8 gm/dl Anemia TLC 4000-11000 / mm3 3000/ mm3 Granulocytopenia Platelet Count 130,000-400000/mm3 80,000/mm3 Thrombocytopenia Spleen size Not enlarged Enlarged Splenomegaly Aplastic anemia may present with anemia and pancytopenia but not with an associated enlarged spleen. If splenomegaly is present the diagnosis of aplastic anemia is seriously questioned.' - Robbins Megaloblastic anemia: Besides ineffective synthesis and increased hemolytic destruction of red blood cells, there also occurs premature destruction of granulocytes and platelet resulting in Leucopenia and thrombocytopenia -Pancytopenia (Robbins) An enlarged spleen may be associated. Leukemia :Aleukemic form of Acute Lymphocytic leukemia also explains both - pancytopenia and hepatosplenomegaly A chronic disease associated with splenomegaly also explains pancytopenia as a sequels to increased destruction as a manifestation of 1-1YPERSPLENISM' (increased sequestration and destruction of cells in sinusoids of an enlarged spleen).