Abstract
Appendiceal cancer is rare after appendectomy ; there have been 13 cases reported in Japan. A case of appendiceal cancer 12 years after appendectomy, which was suspected to be neuroendocrine carcinoma on histopathology, is described. A 51-year-old man who underwent an appendectomy 12 years earlier was found to have occult blood on stool examination. He was admitted to our hospital with suspected appendiceal cancer on colonoscopy. The intra-operative findings showed that the tumor invaded aggressively to the small intestine and mesentery. Thus, the patient underwent right hemicolectomy. On macroscopic examination, the specimen appeared to be a submucosal tumor. In other words, the tumor pushed up the mucosa toward the appendiceal orifice. Moreover, the side of the mucosa was intact. The results of immunostaining with chromogranin A, synaptophysin, and NSE, which are specific for neuroendocrine tumors, were negative. However, hematoxylin and eosin staining strongly suggested neuroendocrine carcinoma. Based on the above results, the tumor was diagnosed as appendiceal cancer.
