<prompt> Massive splenomegaly is least likely to occur inCMLPrimary thrombocytosisPCVPrimary myelofibrosis  <response>: Thrombocytosis is defined as a platelet count greater than 400 x 109L. ... The presence of chronic thrombocytosis, thrombohemorrhagic complications, microvascular symptoms, or splenomegaly ors the diagnosis of primary thrombocytosis. Spleenomegaly is least likely to occur. Ref ganongs review of medical physiology 25e 