Juvenile myelomonocytic leukemia in a child with Crohn disease.

Intestinal adenocarcinoma is a well-known complication of inflammatory bowel disease. Hematologic malignancies, most commonly lymphoma or acute myeloid leukemia, represent a much less well-recognized complication of these disorders; these typically occur in adults with ulcerative colitis. We report a fatal case of juvenile myelomonocytic leukemia associated with monosomy 7 in a young child with a clinical history of Crohn disease. Neither the leukemia nor the cytogenetic aberration has been previously reported in a patient with inflammatory bowel disease. The aggressive disease course emphasizes the need for proper recognition and further study of this unusual complication.