Pericarditis as a manifestation of essential thrombocythemia.

A 58-year-old woman presented with pericarditis and pericardial effusion. Investigation revealed that she was suffering from a thrombocythemic myeloproliferative disorder; she died of massive pulmonary embolism 10 days after admission. Histologic study verified epicardial and pericardial trilineage hematopoiesis. Pericarditis is an unusual feature of essential thrombocythemia and it may occur in direct relation to the abnormal cellular proliferation.