So-called carcinosarcoma of the duodenum with a chondrosarcomatous component.

Carcinosarcoma is a biphasic malignant tumor consisting of both carcinomatous and sarcomatous components, and its occurrence in the duodenum is very rare. In the present report, we describe a case of so-called carcinosarcoma of the duodenum with a chondrosarcomatous component. A 79-year-old man was referred to our hospital because of anorexia, weight loss, and jaundice. A preoperative imaging examination showed a hypovascular mass located in the pancreatic head. Histological examination of specimens obtained through a forceps biopsy revealed anaplastic carcinoma (spindle cell type), and a pancreatoduodenectomy was performed. Histologically, the tumor showed an elevated lesion with a wide base in proximity to duodenal mucosal carcinoma. The tumor was found to be predominantly composed of sarcoma with carcinomatous and chondrosarcomatous components. There was a transitional zone between the carcinomatous and sarcomatous components, and a portion of the sarcomatous component was positive for cytokeratin, and negative for vimentin. As mentioned above, we diagnosed the lesion as so-called carcinosarcoma with a chondrosarcomatous component.