Two Histologically Different Primary Malignancies: Synchronous Obstructive Descending Colon Adenocarcinoma and Appendicular Carcinoid Tumor

BACKGROUND Synchronous primary tumors are defined as 2 or more different histological tumors discovered in one patient at the same time or within a period of 6 months. Colorectal cancer is one of the most common cancers in the United States. Inversely, synchronous colorectal cancer and carcinoid tumors are rare. Carcinoid tumors can be classified into functioning and non-functioning tumors. Carcinoid tumors are steadily increasing in incidence. There is only 1 case reported in the literature as synchronous colorectal cancer and appendicular carcinoid. The difficulty is to manage 2 different types of malignancies at the same time. An optimal medical or chemotherapy strategy is needed. CASE REPORT A 29-year-old woman presented to the emergency room carrying with her computerized tomography (CT) abdomen and pelvic images showing bowel obstruction. Investigations confirmed an obstructing descending colon mass. She underwent colonoscopic stenting as emergency treatment with multiple biopsies. The pathology report came back positive for adenocarcinoma, and we planned to proceed with surgery. Intraoperatively, she was found to have an appendicular mass. The surgical team decided to proceed with laparoscopic-assisted subtotal colectomy. The postoperative course was uneventful, with no complications. The patient was discharged on postoperative day 6 in stable condition. CONCLUSIONS Synchronous colorectal cancer and carcinoid tumors are rare malignancies. The challenge is to find an optimal medical or chemotherapy strategy to manage both malignancies.