Giant platelet disorders in African-American children misdiagnosed as idiopathic thrombocytopenic purpura

A retrospective chart review of six African-American children with a diagno sis of macrothrombocytopenias (MTCP) was performed to evaluate the accuracy of their diagnosis. The following was diagnosed in the six children with M TCP: Fechtner syndrome (two children), Sebastian syndrome (one child), and unnamed MTCP (three children). In five families, chronic idiopathic thrombo cytopenic purpura (ITP) was diagnosed in the propositus, which resulted in therapy using steroids, intravenous immunoglobulin (IVIG), and in one case splenectomy. Bleeding symptoms were generally mild. All six patients had th rombocytopenia ranging from 10 to 125 x 10(9)/L with mean platelet volume o f 8 to 20 fL. Bleeding times were abnormal in two of three patients, and pl atelet aggregation was abnormal in three of four patients tested. Bone marr ow aspirates were reported as increased megakaryocytes in the three patient s on whom the procedure was performed. Ultrastructural morphology of platel ets and leukocytes was performed in all six patients demonstrating giant pl atelets in all six patients and leukocyte inclusions in three patients. Dif ferentiating MTCP from the more common ITP can be difficult but important i n avoiding unnecessary diagnostic studies and potentially harmful therapy a ssociated with ITP.