Granulocytic sarcoma of the colon in chronic myelomonocytic leukemia

A 59-year-old man with a six-month history of chronic myelomonocytic leukemia (CMML) was admitted to the Kitasato University Hospital because of melena in September 2000. Colonofiberscopy and barium enema demonstrated an ulcerated tumorous lesion in the transverse colon. The histopathologic findings of the ulcer bed revealed diffuse infiltration of granulocytes at each stage of differentiation. The diagnosis of granulocytic sarcoma (GS) was made. Surgical resection was not indicated, because thrombocytopenia was hardly improved enough to allow surgery despite repetitive transfusion of platelet concentrates. CMML developed to refractory anemia with excess of blast in transformation in February 2001. Two courses of low dose cytarabine plus aclarubicin were ineffective on the GS in spite of a decrease in the peripheral blood blasts. Progression to acute myeloid leukemia eventually broke out, in July 2001. The patient died of leukemia complicated with pneumonia and intestinal obstruction. At present, nine cases of GS in the colon have been reported. However, these cases did not include CMML. This is the first report describing GS in the colon associated with CMML.