Colonic Myeloid Sarcoma as a Rare Presentation of Relapsed Acute Myeloid Leukemia.

Myeloid sarcoma (MS), an extramedullary tumor of immature granulocytic cells, affects the gastrointestinal tract in approximately 10% of cases. MS involvement of the colon and rectum is considered to be extremely rare. We present a 36-year-old woman with acute myeloid leukemia and allogenic hematopoietic stem cell transplant 2 years before who was admitted with abdominal pain and nonmucous, nonbloody diarrhea. Colonoscopy revealed an ulcerated mass in the proximal colon, and biopsies showed MS compatible with acute myeloid leukemia relapse.