Primary colonic adenocarcinoma and synchronous rectal carcinoids are rare tumors. Whenever a synchronous tumor with a nonmetastatic carcinoid component is encountered, its prognosis is determined by the associate malignancy. The discovery of an asymptomatic gastrointestinal carcinoid during the operative treatment of another malignancy will usually only require resection without additional treatment and will have little effect on the prognosis of the individual. This article reports a synchronous rectal carcinoid in a patient with hepatic flexure adenocarcinoma. We present a case of a 46-year-old Hispanic woman with a history of hypothyroidism, uterine fibroids and hypercholesterolemia presenting with a 2-week history of intermittent abdominal pain, mainly in the right upper quadrant. She had no family history of cancers. Physical examination was significant for pallor. Laboratory findings showed microcytic anemia with a hemoglobin of 6.6 g/dl. CT abdomen showed circumferential wall thickening in the ascending colon near the hepatic flexure and pulmonary nodules. Colonoscopy showed hepatic flexure mass and rectal nodule which were biopsied. Pathology showed a moderately differentiated invasive adenocarcinoma of the colon (hepatic flexure mass) and a low-grade neuroendocrine neoplasm (carcinoid of rectum). The patient underwent laparoscopic right hemicolectomy and chemotherapy. In patients diagnosed with adenocarcinoma of the colon and rectum, carcinoids could be missed due to their submucosal location, multicentricity and indolent growth pattern. Studies suggest a closer surveillance of the GI tract for noncarcinoid synchronous malignancy when a carcinoid tumor is detected and vice versa.
Keywords: Adenocarcinoma of colon; Rectal carcinoid; Synchronous tumors.