A Case of Juvenile Endocrine Cell Carcinoma of the Transverse Colon

A 34-year-old man referred for melena and abdominal mass was found, on admission, by abdominal CT and MRI to have a huge left upper abdominal mass. Closer examination showed a suspected mesenchymal tumor arising from the transverse mesocolon, involving the transverse colon and pancreas, necessitating en bloc resection of the tumor by left hemicolectomy, distal pancreatectomy, and splenectomy. The resected 17×11×8 cm, 1, 500g tumor consisted microscopically of atypical polygonal cells proliferating in a solid nest with abundant eosinophilic cytoplasm. Immunohistochemically, tumor cells were positive for synaptophysin, chromogranin A, and neuronal-specific enolase (NSE) and the tumor was diagnosed as endocrine cell carcinoma. The patient underwent adjuvant chemotherapy with CDDP and CPT-11, but died due to local recurrence, liver metastasis, and peritonitis carcinomatosa 7 months after surgery. The prognosis of colorectal endocrine cell carcinoma is dismal, requiring effective intensive treatment, including neoadjuvant chemotherapy and radiation.