Diffuse Large B Cell Lymphoma of the Rectosigmoid Junction: Case Report and Literature Review
A 67-year-old male patient with a one month history of abdominal pain was referred to the surgery ward of Shariati Hospital in Tehran, Iran. There had been a gradual onset of pain over the peri-umbilical and hypogastric region and the patient reported a loss of appetite and 10 kg weight loss within the past three months. The pain did not change with respect to the patient’s position or with eating. He also complained of nausea and vomiting that began one week earlier which had progressed to a partial obstruction as evidenced by the lack of defecation for three days. In addition, there was urinary frequency and urgency associated with this presentation; however, there was no incontinency or hematuria. The patient’s medical history was unremarkable except for a history of smoking (15 pack–years). Physical examination revealed an ill-defined mass in the lower hypogastrium, moderate abdominal distention, and tenderness in the hypogastric region. The remainder of the examination was unremarkable. Laboratory analyses were normal except for a Hb of 9.6 g /dl.\nThe imaging studies performed showed a normal chest X-ray, but the abdominal imaging study revealed the presence of air-fluid levels suggestive of obstruction. Abdominopelvic CT scan showed a bulky soft-tissue density mural mass in the distal sigmoid that extended to the proximal rectum within the anterior wall with accompanying enlargement of regional lymph nodes (). There were no other cervical, thoracic, or pelvic lesions. Pelvic MRI confirmed the abdominopelvic CT scan findings as a large homogeneous T1 hypointense and mildly T2 hyperintense mural mass in the rectosigmoid junction with moderate contrast enhancement (and).\nA colonoscopy was performed which showed normal mucosa with an extra-luminal mass effect noted in the upper rectum. Endorectal ultrasonography (EUS) showed a hypoechoic mass in the extraluminal superior part of the rectal area. EUS-guided needle biopsy was performed and the histological examination suggested a malignant transformation with no definite diagnosis(,).\nThe patient underwent surgical resection due to tumor location (no distant involvement) and evidence of worsening symptoms (abdominal pain and change in bowel habits). Intra-operative findings included dilation of the small and large bowel along with the presence of a pelvic mass that extended to the retroperitoneal region, a loop of ileum, and bladder. The mass was predominantly located in the distal sigmoid and superior rectum. Intra-operative biopsy and subsequent frozen section study were all suspicious for malignancy but not conclusive for the tumor type. The mass was debulked by resection of the upper rectum, sigmoid and parts of the ileum. The small bowel was repaired by primary hand-sewn anastomosis. End-to-end anastomosis of the left colon to the rectum was not possible due to involvement of the rectal margin and necessitation of a complete en-block resection. The bladder was also resected to some extent in the involved sections. An end colostomy was performed and the Hartman pouch was left open to allow for drainage by a Pezzer drain through the abdomen. The patient had an uneventful postoperative recovery and was discharged after five days from the surgical ward after which he referred to the oncology clinic for additional evaluation and adjuvant chemotherapy.\nPathologic assessment was done using immunohistochemistry (IHC) staining (positive for CD20 and Ki67) which showed diffuse infiltration of cleaved and non-cleaved cells within the intestinal wall that involved the submucosa and muscularis layers, and the serosa. Diffuse large B cell lymphoma was the confirmed diagnosis with invasion to the intestinal wall and induced ulceration in the sigmoid colon, small intestine and rectum.\nFollowing surgery and recovery, the patient underwent CHOP chemotherapy. After 18 months of follow-up the patient remains disease-free according to paraclinical and radiologic studies. He suffers only from a limited incisional hernia which has been managed non-operatively with an elastic abdominal corset. No attempt has been made to establish intestinal continuity because of an unsuitable rectal pouch and the patient’s general condition.