Myeloid Sarcoma: Recurrence after Therapy for AML with Bone Marrow Transplant Presenting as Colon Polyps

Abstract

Purpose: A 55-year-old man with a history of alcohol cirrhosis and acute mylogenous leukemia (AML) status post allogenic bone marrow transplant presented to the emergency department with abdominal pain and episodic hematochezia for seven days. The patient's AML was in remission, with one episode of graft versus host as his only complication of therapy. His initial evaluation was notable for stable hemodynamics, heme positive brown stool, a hemoglobin of 11.5 g/dL, and macrocystosis. Gastroenterology was consulted, and he underwent colonoscopy and upper endoscopy. EGD was significant for grade 1, non-bleeding esophageal varices and mild portal hypertensive gastropathy. Three colon polyps, five, seven, and 10 mm, respectively, were identified and resected on colonoscopy; the remainder of the colonic mucosa was normal. The pathology report showed an expansion of the lamina propria by immature myeloblasts that strongly expressed CD34, CD117, and myeloperoxidase, confirming the diagnosis of myeloid sarcoma. The largest of the polyps additionally showed tubulovillous adenoma features. Hematology consultation felt this represented leukemic transformation of his previous disease. The patient decided not to seek re-treatment for this finding. Myeloid sarcoma, also known as a chloroma or granulocytic sarcoma, is a tumor composed of myeloid blast cells. This represents a known extramedullary manifestation of acute myeloid leukemia. Myeloid sarcoma as a recurrent manifestation after stem cell or bone marrow transplant is a rare complication of myelodysplastic disorders. Gastrointestinal recurrence of myeloid sarcoma is an almost nonexistent finding. The most common sites of recurrence are CNS, testis, ovaries, and periosteal lesions. Gastrointestinal manifestations account for less than 5% of recurrent sarcomas. Colon involvement is a small subset of GI disease, with most cases endoscopically appearing as diffuse ulceration of colonic mucosa rather than discrete colon polyps. Myeloid sarcoma presenting in tandem with AML is a well-described entity. Two features of this case contribute to the rarity. First, myeloid sarcoma presenting as the only manifestation of AML recurrence, and secondly, this recurrence presenting as discrete colon polyps. This case demonstrates an exceedingly uncommon presentation of a rare recurrence of AML. This highlights the importance that a gastroenterologist can play in the evaluation and diagnosis of a systemic disease that can mimic as a commonly encountered gastrointestinal symptom.