A case of follicular lymphoma involving the colon

A 77-year-old Japanese man was referred to Kagawa Prefectural Central Hospital for further investigation of a positive fecal occult blood test. Colonoscopy revealed an elevated lesion of 35 mm in diameter in the ascending colon. The lesion had a submucosal tumor-like morphology, lacking erosions or ulcers. Histological examination of the biopsy specimen revealed dense infiltration of small-sized neoplastic lymphoid cells. Based on the immunohistochemical examinations, the colonic tumor was diagnosed as follicular lymphoma. CT scanning revealed systemic lymph-adenopathy in addition to the colonic tumor. Six courses of CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy plus rituximab were administered as the first-line treatment. After completion of the regimen, the colonic tumor had disappeared and the lymph-adenopathy had partially regressed. However, a mesenteric lymph node had become enlarged. Bendamustine was therefore administered to treat the relapse of follicular lymphoma. Among the various parts of the gastrointestinal tract, the small intestines (especially the duodenum) are the most common site of follicular lymphoma involvement, and the colorectum is less frequently affected. This paper illustrates a rare case of systemic follicular lymphoma with colonic involvement.