S1911 Primary Colon Burkitt’s Lymphoma Presenting as Colonic Obstruction

Abstract

Introduction: Primary colon lymphomas are very rare colon malignancies and Burkitt´s lymphoma (BL) variant is usually diagnosed in children and immunocompromised patients. BL is a highly aggressive malignancy and is the fastest growing human cancer. Primary colon BL (PCBL) is very rare in adults with few reported cases located around ileocecal valve region. There are only two published cases of PCBL causing colonic obstruction due to ileocecal valve region involvement. We present a unique PCBL case located in splenic flexure of colon causing colonic obstruction. Case description/methods: A 56-year-old female presented with 10-day history of worsening diffuse abdominal pain, nausea, vomiting & inability to pass gas. She had diffuse abdominal tenderness & hyperactive bowel sounds. Labs were unremarkable. Abdominal CT scan revealed complete colonic obstruction from splenic flexure exophytic colonic mass measuring 14 x 10 x 10 cm with small mesenteric & hepatic lesions. Emergent laparoscopic transverse colon diverting loop colostomy performed due to high tumor burden that appeared to be unresectable. Subsequent colonoscopy showed large obstructing colon mass at splenic flexure of colon & proximal colon segments were dilated with decompressed distal colon. Biopsies from colon mass were indicative for diffuse large B-cell lymphoma with extensive necrosis, high proliferation index, Ki-67 80% positive. Ultrasound guided liver biopsy revealed high grade B-cell lymphoma. FISH analysis revealed findings of MYC/IGH fusion in approximately 100% of nuclei without rearrangement of BCL2 or BCL6, consistent with PCBL. Chemotherapy initiated (etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, rituximab) with an excellent response. Surveillance colonoscopy at 5-year post-treatment showed no concerns for disease recurrence. Discussion: PCBL is not only very rare in adults but also rare outside of ileocecal area, where concentration of lymphoid tissue is relatively increased. In english literature there are only 2 published cases of PCBL at ileocecal valve location causing colonic obstruction. To the best of our knowledge, our PCBL case is unique as being the first case of PCBL atypically located in distal colon & causing colonic obstruction. Older age or atypical GI locations cannot exclude the possibility of PCBL & should be considered as part of differential diagnosis for high-grade GI lymphomas. With advances in chemotherapy, PCBL may respond well to therapy even in disseminated stage with colonic obstruction.Figure 1.: A: Nuclear medicine PET CT scan showing multiple FDG avid mesenteric masses consistent with lymphoma and evidence of hepatic metastasis. Figure B: CT scan abdomen revealing large splenic flexure exophytic colonic mass causing colonic obstruction. Figure C: Large obstructing colon mass seen at the splenic flexure of colon during colonoscopy. Figure D: Colon mass biopsy with hematoxylin & eosin stain at 200x magnification showing extensive necrosis with crush artifact and rare clusters of viable large neoplastic cells.