Diffuse Large B-Cell Lymphoma of Recto-Sigmoid Colon

Abstract

Primary colorectal lymphoma (PCL) is a rare malignancy accounting for 3% of all GI lymphomas and 0.1-0.5% of all colorectal malignancies. The most frequent colonic location is the cecum followed by the rectum and ascending colon. Although several cases of PCL have been reported in the literature the recto-sigmoid junction as an origin has rarely been reported. We present a rare case of diffuse large B- cell lymphoma (DLBCL) in a patient presenting with anemia, weight loss and change in bowel habits. A 79 year old male with a past medical history significant for adenocarcinoma of the prostate status post (s/p) radiation, coronary artery disease s/p CABG, chronic kidney disease admitted to Dartmouth Hitchcock Medical Center (DHMC) with complaints 30 pound weight loss, intermittent lower abdominal pain with alternating diarrhea and constipation. Of note, one month prior to admission, he underwent colonoscopy at an outside hospital due to changes in his bowel habits. Biopsies taken at the time revealed non-specific acute inflammation thought to be related to ischemic colitis. During his admission at DHMC he underwent CT scan abdomen and pelvis which revealed thickening of the recto-sigmoid colon. Subsequent colonoscopy showed a colonic mucosa characterized by circumferential ulcerations with mucopurulent exudate that extended from rectum to sigmoid colon (Figure 1). The appearance was suggestive of ischemic colitis, but rectal involvement seemed atypical. Biopsies taken were stained for hematoxylin and eosin and immunohistochemistry to reveal diffuse DLBCL of the colon.Figure 1A PET-CT scan showed hypermetabolic activity involving lung, kidney, sigmoid and rectum. This was consistent with stage IVB DLBCL with extra-nodal involvement and 4 year survival of 40-50%. The patient underwent treatment with R-CHOP (Rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) however did not tolerate treatment due to worsening kidney and functional decline. He was transitioned to hospice care per family wishes and died one month later. The most common histological subtype of colorectal lymphoma is DLCBL. The etiology of DLBCL is unknown. Patient may present with variety of clinical symptoms that include abdominal pain, anorexia, weight loss, fatigue, anemia, fever, constipation and/or diarrhea. However, due to the nonspecific presentation diagnosis maybe delayed as seen in our patient. One should consider PCL in patient presenting with the above symptoms or with risk factors including HIV, organ transplant, inflammatory bowel disease and immunosuppressant agents. Endoscopists should think of a broader differential diagnosis when proctitis or colitis is seen during colonoscopy. Biopsies should be taken and reviewed by an expert GI pathologist.Figure 2