Thrombocytosis in Malignancy: A Paraneoplastic Syndrome?

Abstract

An increased platelet number may be secondary to many conditions. Malignancies are known to induce thrombocytosis in some cases.

We report data of paraneoplastic thrombocytosis recognized in 54 out of 159 patient (33.9%) with reactive thrombocytosis diagnosed in our department over the last 10 years. In most of our patients increased platelet count was observed at the time of diagnosis (33.7%) or during the first year thereafter (35.2%). Evidence of other causes for reactive thrombocytosis including iron deficiency, anemia, inflammatory diseases, surgical procedures including splenectomy, and drugs were observed in 74% of our patients. 35% of our subjects had non fatal hemorrhagic or thrombotic accidents. In about one half of our patients, increased levels of fibrinogen, ESR and plasma alpha2 globulins were observed while 5 hydroxytryptamine (5HT) intraplatelet level was normal in about all these patients. The diagnosis of paraneoplastic thrombocytosis must be postulated only after exclusion of all other reactive conditions. Often an increased platelet count in patients with cancer may be considered a reactive phenomenon.

Keywords:

• Thrombocytosis
• malignancies
• serotonin