Synchronous Small Intestinal Tumors: Discrete Duodenal Carcinoid and Adenocarcinoma

Abstract

Introduction: A 49-year-old white female with diabetes mellitus type 2, coronary artery disease, myotonic muscular dystrophy, morbid obesity, and obstructive sleep apnea underwent evaluation for chronic fatigue, intermittent vomiting, diarrhea, and iron deficiency anemia. Endoscopy revealed nodular, congested duodenal bulb mucosa and a circumferential, protruding partially obstructing mass in the third portion of the duodenum (D3). Colonoscopy was unremarkable. Celiac serologies were negative and duodenal biopsies were without evidence of sprue. Duodenal bulb pathology revealed a low-grade neuroendocrine neoplasm with positive immunostain for synaptophysin, supporting a diagnosis of carcinoid. D3 mass pathology revealed a well-differentiated adenocarcinoma. She was deemed a poor surgical candidate due to extensive cardiac, pulmonary, and dystrophic muscular co-morbidities. After shared decision making, she was referred for palliative chemotherapy and radiation. Risk factors for small bowel adenocarcinoma include male gender, age greater 60, smoking, Crohn’s disease, celiac disease, and personal/family history of colon cancer. Carcinoid tumors are seen in multiple endocrine neoplasia, neurofibromatosis, and more frequently in African Americans than Caucasians. Myotonic dystrophy may explain the early onset of disease and absence of traditional disease risk factors. Myotonic dystrophy is an inherited, autosomal dominant group of diseases, resulting from repeat, unstable nucleotide expansions that can demonstrate genetic anticipation. This inheritance pattern and presence of genetic disorder may explain the early onset and concurrence of these 2 rare small bowel tumors. Composite tumors with areas of adenocarcinoma and carcinoid in the same tumor have been reported in the stomach, duodenum, ampulla, liver, appendix, colon, and rectum. A collision-type tumor involves adjacent, but separate components of carcinoid tumor and adenocarcinoma. We report the first case of separate small bowel carcinoid and adenocarcinoma in a young myotonic dystrophy patient.Figure 1