A case of thyrotoxicosis with pancytopenia

We report a 49-year-old man with primary hyperthyroidism who presented with pancytopenia. The patient presented with leg, edema, sinus tachycardia, ca rdiomegaly, and pleural effusions, all from congestive heart failure. Labor atory data showed pancytopenia and primary hyperthyroidism; echocardiogram showed diffuse hyperkinesis of the left ventricular wall and right ventricu lar overloading. The bone marrow was moderately hypercellular and compatibl e with arrested hematopoiesis. Pancytopenia and heart failure improved afte r administration of methimazole and diuretics. However, high levels of thyr oid hormone recurred with pancytopenia 4 months after admission. Therefore, subtotal thyroidectomy was performed, and the levels of thyroid hormones a nd peripheral blood cell counts have remained normal. Pancytopenia may be c aused by hyperthyroidism.