Abstract
A 29-year-old man visited our hospital because of appetite loss and fatigue. Gastroscopy failed to identify the bleeding source. Abdominal computed tomography (CT) showed a target sign. Jejunal intussusception caused by a small intestinal tumor was diagnosed and laparoscopic assisted operation was performed. The oral side jejunum was intussuscepted into the lumen of the anal side jejunum led by soft tumor. A soft tumor was shown in the distal end of the intussusception. The tumor was located in the jejunum 30 cm distally to the Treitz's ligament. Partial jejunectomy was performed. The resected specimen revealed a Isp tumor, measuring 55×40×35 mm. Histopathological examination of the resected tumor revealed well-differentiated adenocarcinoma with tubular adenoma components. It was confined to the mucosa. In this patient with adolescent small-bowel cancer, which was suggestive of Lynch syndrome, we performed microsatellite instability analysis of the tumor. Molecular testing showed microsatellite stability. Primary jejunal cancer with adenoma components is rare and this case suggests a relationship between adenomas and carcinomas of the small intestine.
