This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Physiology
Massive splenomegaly is least likely to occur in 
Select and explain. 
A. CML, B. Primary thrombocytosis, C. PCV, D. Primary myelofibrosis
B: Primary thrombocytosis
Answer: B: Primary thrombocytosis 
Explanation: Thrombocytosis is defined as a platelet count greater than 400 x 109/L. ... The presence of chronic thrombocytosis, thrombohemorrhagic complications, microvascular symptoms, or splenomegaly ors the diagnosis of primary thrombocytosis. Spleenomegaly is least likely to occur. Ref ganong's review of medical physiology 25e