S1748 Primary Follicular Lymphoma of the Colon: A Rare Case in a Rare Place

Abstract

INTRODUCTION: Primary lymphomas of the colon are rare, accounting for < 1% of all GI malignances. Studies describing the disease suggest that it most commonly involves the cecum and presents symptomatically in patients with abdominal pain and weight loss. However, given the rarity of the cancer, literature on the clinical and pathologic features of the disease are still evolving. Here, we present a case of primary follicular lymphoma affecting the sigmoid colon with a description of the corresponding colonoscopy and histologic findings. CASE DESCRIPTION/METHODS: The patient is a 71-year old female referred from her PCP for iron deficiency anemia with a hemoglobin of 11.3 g/dL and positive fecal immunochemical testing (FIT). Her symptoms included intermittent episodes of constipation for several weeks. She denied changes in stool caliber including bloody or tarry appearing stools, B-symptoms such as weight loss or night sweats, or family history of colorectal malignancy. Physical exam was unremarkable. Subsequent colonoscopy revealed an 8mm sessile polyp and 10mm semi-pedunculated polyp with a localized area of nodular mucosa in the sigmoid colon. Polyp and mucosal biopsies demonstrated atypical lymphoid infiltrate with abnormal follicular proliferation positive for CD-20, BCL-2 and BCL-6, consistent with low-grade, stage IE, follicular lymphoma. At 1-month follow-up with oncology, the patient remained asymptomatic after polypectomy and chose conservative management with active surveillance. DISCUSSION: Primary lymphoma of the colon is rare, accounting for less than 0.2% of all GI malignancies. There is limited data on the clinical and pathologic features of the disease however, current studies indicate a female predominance, chief presenting symptoms of abdominal pain and weight-loss, and largely cecum involvement. Here, we present a rare case of follicular lymphoma in the sigmoid colon of a female presenting with constipation and iron deficiency anemia. Colonoscopic features included a sessile and semi-pedunculated polyp with nodular mucosa and histology showing an atypical lymphoid infiltrate positive for CD-20, BCL-2, and BCL-6. This case provides insight both into the varying clinical and pathologic characteristics of a relatively rare disease and the importance of lymphoma as part of the differential in this patient population.Figure 1.: Colonoscopy demonstrating a 10-mm Semi-pedunculated Polyp of the sigmoid.Figure 2.: Nodular Hyperplasia of the sigmoid colon.Figure 3.: Biopsy specimen with the round follicles characteristic of follicular lymphoma seen on histology (arrows).