T-cell acute lymphoblastic leukemia with transient pure red cell aplasia associated with myasthenia gravis and invasive thymoma.

A 43-year-old male developed rapidly progressing anemia and a bone marrow examination revealed pure red cell aplasia (PRCA). He was diagnosed as having myasthenia gravis (MG) and invasive thymoma, and achieved complete remission by radiation and chemotherapy six years ago. Despite increased doses of oral prednisolone from 7.5 mg/day to 60 mg/day, a diagnosis of T-cell acute lymphoblastic leukemia (T-ALL) was made one month later based on findings of 37.2% abnormal lymphoblasts and positive surface markers for CD2, CD3 and CD7 T-cells. Cases of PRCA associated with MG and thymoma have been reported in the literature, however such a case followed by T-ALL is very rare.