A case of synchronous extranodal marginal zone B-cell lymphoma and adenocarcinoma in the sigmoid colon

초록

Extranodal marginal zone lymphomas (EMZLs) are derivative of marginal zone lymphomas (MZLs), develop in extranodal tissues, especially in mucosa-associated lymphoid tissue (MALT). It usually infiltrates to stomach (50~70% of all EMZL), less frequently the esophagus, conjunctiva, small and large intestine. Colonic EMZLs involvement is extremely rare. There are only 50 case reports from 1993 to 2017 in PubMed search on English medical literature. Moreover, a case of synchronous colon EMZL and adenocarcinoma is even rarer. We report a rare case of EMZL with a co-existing of adenocarcinoma in the sigmoid colon and discuss proper evaluation and management. A 59-year-old male presented complaints of diarrhea and abdominal discomfort. He was evaluated after a recent colonoscopy, which disclosed a huge ulcerofungating mass with luminal stricture in the rectosigmoid colon. The colonoscope failed to pass through the rectosigmoid junction because of this obstructing colon mass. Biopsy results showed a moderately differentiated adenocarcinoma. An abdominal computed tomography displayed irregular wall thickened lesion with pericolic abscess, involving sigmoid colon extending for a length of approximately 8 cm length and significant lymphadenopathy in sigmoid mesocolon and bilateral iliac chains. There was no evidence of distant metastases on computed tomography of the chest and abdomen. Physical examination findings were unremarkable except for mild low abdominal discomfort. The patient underwent an open anterior resection with a diverting stoma. Surgical exploration showed hugely dilated redundant omega-shaped sigmoid colon, and an abscess pocket locating between the sigmoid colon and the dome of the bladder. Histopathological analysis showed pT2pN0 moderately differentiated adenocarcinoma. Immunohistochemical stains revealed lymphoproliferative lesions in the colonic mucosa that expressed CD 20, Bcl-2 and Ki-67 labelling index (15%), consistent with colonic EMZL. Based upon th