Recurrent venous thrombosis: the sole manifestation of an occult myeloproliferative disease.

A myeloproliferative disorder manifested by thrombocytosis, a high leukocyte alkaline phosphatase (LAP) score and an increased red blood cell mass was found in a 64-yr-old woman. During the previous 15 yr, recurrent venous occlusions had taken place, necessitating the resection of ischemic bowel segments and leading to extrahepatic portal venous obstruction. Numerous blood counts obtained during repeated hospitalizations were normal, and these thrombotic events remained unexplained. The sequence of events strongly suggests that the myeloproliferative disorder existed in an occult form during these years and was responsible for the venous occlusions. The possibility of a "smoldering" myeloproliferative disorder should be considered in patients with otherwise inexplicable thrombotic phenomena.