Temporary remission of an alveolar rhabdomyosarcoma diagnosed and treated as acute leukemia.

A 29-year-old man with alveolar rhabdomyosarcoma was considered to be suffering from acute leukemia. A bone marrow aspirate had revealed extensive infiltration by atypical blast-like cells which were interpreted as acute lymphoblastic leukemia. Although there was no confirmation of this diagnosis by immunophenotyping chemotherapy with a protocol suited for the treatment of acute lymphoblastic leukemia was started prior to histological analysis and resulted in a complete temporary remission after the first cycle. Histological analysis of a bone marrow biopsy revealed an alveolar rhabdomyosarcoma, as further confirmed by molecular genetic analysis. Two months after the end of chemotherapy, there was an extensive recurrence and the patient died one year after initial diagnosis with chemotherapy refractory disease. In conclusion, rhabdomyosarcoma should always be included in the differential diagnosis of systemic diseases with extensive bone marrow infiltration by tumor cells which could otherwise be misinterpreted as a haematological malignancy.