A 26-year-old woman presented with pain in the left hypochondrium, for which pancreatectomy and splenectomy was performed, with total gross excision of a mass. A tumor measuring 11 x 9 cm was found in the pancreas. On cut surface there were two cysts filled with a necrotic substance and hemorrhagic content. Spindle or ovoid-shaped cells, in the sarcomatous component, had diffusely infiltrated along the inner side of the walls of one cyst. Osteoclast-like giant cells (OGC) were also contained in the sarcomatous component. Adenoma components of mucinous epithelium with foci of borderline and adenocarcinomatous components were seen on the inner side of the other cyst. An ovarian-type stroma beneath the epithelial component was seen in the cyst wall. A diagnosis of undifferentiated carcinoma with OGC arising in a mucinous cystic neoplasm (MCN) of the pancreas, was made. Seven months after the initial operation the patient had a local recurrence, and the tumor was removed. One month after the second operation, the patient was free of symptoms. Only four cases of undifferentiated carcinoma with OGC arising in MCN, involving an ovarian-type stroma of the pancreas, have been reported.

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Hyperplastic polyps (HPs) of the stomach have been reported to be mostly benign. However, in rare cases, carcinomas have been found in HPs. We treated a 59-year-old Japanese male who underwent a total gastrectomy, and a gross examination of the resected stomach revealed a 4.8 x 3.8-cm polyp on the greater curvature of the antrum and multiple small polyps in the whole gastric mucosa. Histologically, the large polyp consisted mainly of hyperplastic foveolar epithelium, while the presence of variously colored lobules demonstrated a poorly differentiated adenocarcinoma mixed with signet-ring cell carcinoma. Hyperplastic polyps should therefore be carefully examined microscopically as a polypectomy specimen and in resected stomach specimens.

An 80-year-old woman with a pleomorphic carcinoma (PC) producing hCG was admitted to Nippon Steel Hirohata Hospital because of an abnormal shadow on CT seen during a follow-up examination after surgery for breast cancer. A right upper lobectomy was performed due to rapid growth of the shadow 3 months later. Macroscopically the tumor was a 4.8 x 4.0 cm well-circumscribed grayish-white mass. On histology the tumor consisted mostly of intermingled spindle and polygonal cells, while evidence of poorly differentiated adenocarcinoma was seen in a few areas. A diagnosis of PC was made due to hCG expression in approximately 20% of the spindle and polygonal cells on immunohistology. Six months after the operation metastasis to the liver and adrenal gland was seen on CT. The patient died due to metastases 1 year after the operation, even though the patient had been at stage 1B at the time of the operation and appropriate chemotherapy had been given. PC patients with immunohistochemical hCG expression have elevated risk of local recurrence and metastasis.

We examined the expressions of adhesion molecules (E-cadherin, beta-catenin, CD44s, and CD44v6) and Ki-67 labeling index (Ki-67 LI) in low- and moderate-grade dysplasia and invasive carcinoma components in ten noninvasive intraductal papillary mucinous neoplasms (IPMNs) of the pancreas and eight invasive carcinomas associated with IPMNs of the pancreas using immunohistochemical methods. There was no significant difference in regard to the proportion of components expressing either E-cadherin or beta-catenin in more than 70% of the tumor cells between the low- and moderate-grade dysplasia components. In contrast, the proportion of those in invasive carcinoma components was significantly lower than in low- or moderate-grade dysplasia components. Also, there was no significant difference in the proportion of components expressing CD44s or CD44v6 in more than 5% of tumor cells among low-grade dysplasia, moderate-grade dysplasia, and invasive carcinoma components. In contrast, the Ki-67 LI values increased in the order of low-grade dysplasia, moderate-grade dysplasia, and invasive carcinoma components, with significant differences among them. The present results indicate that carcinoma components are associated with a decrease in tumor cells expressing E-cadherin and beta-catenin and have the highest proliferative activity.