Macrocytic anemia and thrombocytosis associated with thymoma: A case report

Thymomas are often associated with autoimmune disorders, We report on a 45- year-old female patient with thymoma and hypogammaglobulinemia (Good's synd rome) who developed symptomatic macrocytic anemia (Hb 4.4 g/dl, MCV 112 fl) and thrombocytosis (Plt 442 G/I). Besides hypogammaglobulinemia (IgG 589 m g/dl), an inverted ratio of CD4(+)/CD8(+) cells was seen. The bone marrow b iopsy showed a slightly hypercellular bone marrow with normal granulopoiesi s, normal megakaryopoiesis and a mild dyserythropoiesis without any ring-si deroblasts. The in-vitro stem cell culture from the bone marrow revealed an atypical growth of macroclusters, reduced BFU-E and CFU-GEMM colony growth , whereas the CFU-GM colony growth was within the normal range. The chromos omal analysis showed a normal karyotype. The plasma vitamin B-12 and folate levels were within normal ranges, and we could not detect any autoantibodi es. These findings excluded the differential diagnoses pure red cell aplasi a (PRCA) and pernicious anemia. After resection of the thymoma of mixed cel l type, the macrocytic anemia and thrombocytosis disappeared. The clinical course was complicated by a cerebral palsy and a life-threatening fungal se pticemia after surgery. In the third year after thymectomy, hyporegenerativ e macrocytic anemia and thrombocytosis reappeared and an immunosuppressive treatment with prednisolone (1 mg/kg BW) was started. After initiation of t he prednisolone therapy, reticulocyte counts increased and macrocytic anemi a as well as thrombocytosis disappeared. The normalization of these laborat ory parameters during glucocorticoid therapy suggests that in rare cases th e constellation of macrocytic anemia, thrombocytosis and hypogammaglobuline mia may be due to an underlying immunologic mechanism, (C) 2000 Wiley-Liss, Inc.