#00012567

A12-year-old boy with Fanconi anemia presented with a 3-week history of painless, circular, bluish skin lesions, up to 15 cm in diameter, most prominently seen on the lateral portions of his right upper leg (see figure, top left). He was afebrile with anemia (Hb 90 g/L) and thrombocytopenia, but a normal leukocyte count. There were no blasts in the peripheral blood smear. A skin biopsy showed an infiltration with myelomonocytic, POX-positive and NACE-positive blast cells, compatible with acute myelogenous leukemia (AML), French-American-British (FAB) subtype M4 (see figure, right). The bone marrow was hypocellular without evidence of acute leukemia. Treatment resulted in a complete remission, but the patient died with disseminated adenovirus following an allogeneic bone marrow transplantation. Bone marrow failure and acute leukemia are well-known complications of Fanconi anemia. Extramedullary manifestations of AML may be observed in some subtypes of AML, most commonly FAB M2.