Primary clear cell adenocarcinoma of the peritoneum.

We report on a very rare case of peritoneal clear cell adenocarcinomas. A 49-year-old Japanese woman underwent hysterectomy and bilateral salpingo-oophorectomy for endometrial endometrioid adenocarcinoma grade III, which was composed of undifferentiated carcinoma cells (98%) and tubular carcinoma cells (2%). No clear cell adenocarcinoma elements were noted in this tumor. Two peritoneal cystic tumors were detected by imaging modalities around the stomach and spleen, 15 months and 21 months after the follow-up period of the endometrial carcinoma, respectively. These two tumors were surgically resected. They were cystic tumors encapsulated by fibrous capsules and showed the same morphologies. They showed proliferation of carcinoma cells arranged in solid nest, tubular, and papillary patterns. They showed clear cytoplasm positive for periodic acid-Schiff stain, hobnail cells, and occasional hyaline globules. The morphologies fulfilled the criteria of clear cell adenocarcinoma. The morphologies and immunohistochemical findings of the two peritoneal clear cell adenocarcinomas were different from those of endometrial carcinoma. We believe that the two clear cell adenocarcinomas are not metastatic lesions from the endometrial carcinoma of the uterus, and that they are primary clear cell adenocarcinomas of the peritoneum. Our case was characterized by cyst formations and encapsulation in addition to the common histological features of clear cell adenocarcinoma of the uterus and ovary.

Correlation of postoperative recurrence in hepatocellular carcinoma with demethylation of repetitive sequences.

Restriction landmark genomic scanning (RLGS) was utilized to identify novel genomic alterations in hepatocellular carcinoma (HCC). Thirty-one HCC samples were examined by RLGS. Two high intensity spots were common to several RLGS profiles of different HCCs. Nucleotide sequencing and homology search analysis showed that these spots represented repetitive sequences, Human tandem repeat sequence (Genbank, L09552) and centromeric NotI cluster (Genbank, Y10752). These intensified signals were attributable to the occurrence of demethylated areas in the recognition sequence of the NotI site of the corresponding fragments. The intensity of these spots in the RLGS profile reflects their degree of demethylation, which was significantly correlated with postoperative recurrence, even in patients regarded as belonging to the good prognosis group by conventional prognostic factors. Multivariate analysis showed that the intensities of the two spots retained independent prognostic value. This is a new type of predictive factor for HCC based on epigenetic changes in hepatocarcinogenesis, and in the future it is expected to be of great value in making preoperative diagnosis and selecting postoperative therapy.

Minute mixed ductal-endocrine carcinoma of the pancreas with predominant intraductal growth.

We report a rare case of minute (5 mm x 4 mm) mixed ductal-endocrine carcinoma of the pancreas with predominant intraductal growth. A 34-year-old Japanese man was admitted because of elevated serum pancreatic enzymes. Endoscopic retrograde pancreatography revealed an unidentified material of 18 mm within the main pancreatic duct. Stone or parasite with acute pancreatitis was suspected clinically, and the biopsy revealed malignant cells positive for CA19-9, carcinoembryonic antigen (CEA) and synaptophysin. No apparent tumor was identified in the pancreas by various imaging techniques. Resection of pancreatic body and tail was performed. Grossly, the main pancreatic duct in the pancreatic body was occluded by as much as 20 mm. The pancreas had minute carcinoma of 5 mm x 4 mm just around the occluded main pancreatic duct. The tumor cells invaded the main pancreatic duct and spread within it as long as 20 mm. Histologically, the carcinoma had biphasic pattern; one was ductal carcinoma with tubular formations and another was carcinoma with neuroendocrine features. These two elements were admixed, and the ductal element comprised 30% while the endocrine element comprised 70%. The ductal element was immunoreactive for cytokeratins, CEA and CA19-9, while the endocrine element was immunoreactive for chromogranin A and synaptophysin. No immunoreactivity for pancreatic enzymes was noted. Ultrastructural observations showed dense core granules and no zymogen granules. Our case is unique clinically in that the tumor manifested as an intraductal material and no apparent tumor was found by imaging modalities, and pathologically in that the tumor was rare mixed ductal-endocrine carcinoma and the tumor was very small and mainly grew within the main pancreatic duct.