RESUMO
Benign papillary mesothelioma of the peritoneum is an uncommon lesion that is usually discovered by chance during a surgical procedure. This lesion resembles metastatic carcinoma in gross appearance; therefore, intraoperative diagnosis can be difficult. This report presents a case of benign papillary mesothelioma concurrent with gastric cancer. The tumor was located on the hepatogastric ligament and resembled a metastatic peritoneal implant. A pathological review confirmed the diagnosis to be benign papillary mesothelioma.
Assuntos
Adenocarcinoma/patologia , Mesotelioma/patologia , Neoplasias Primárias Múltiplas , Neoplasias Peritoneais/patologia , Neoplasias Gástricas/patologia , Adenocarcinoma/química , Adenocarcinoma/cirurgia , Biomarcadores Tumorais/análise , Biópsia , Gastrectomia , Humanos , Imuno-Histoquímica , Masculino , Mesotelioma/química , Mesotelioma/cirurgia , Pessoa de Meia-Idade , Neoplasias Peritoneais/química , Neoplasias Peritoneais/cirurgia , Valor Preditivo dos Testes , Neoplasias Gástricas/química , Neoplasias Gástricas/cirurgia , Resultado do TratamentoRESUMO
A small cell carcinoma of the extrahepatic bile duct in a 75-year-old Japanese man is reported. The patient suffered from obstructive jaundice, and percutaneous transhepatic cholangiography-drainage (PTCD) revealed a massive lesion in the lower common bile duct. Because it was diagnosed as a malignant tumor, pancreaticoduodenectomy was performed. A nodular infiltrating tumor measuring 4.5 x 3.0 x 2.0 cm was located in the intrapancreatic portion of the extrahepatic bile duct. Histologically, the tumor was composed of a dense proliferation of small atypical cells with a little region of high-grade dysplasia in the adjacent epithelium of the common bile duct. Tumor cells were immunoreactive to neuroendocrine markers such as chromogranin A, synaptophysin, CD56, and Leu7. Although carcinoma cells invaded into pancreas and duodenum, there were no histological findings that indicated the carcinoma arose from the mucosa of either the pancreatic duct or duodenum. These results indicated that the tumor was a small cell carcinoma derived from the epithelium of the extrahepatic bile duct; a rare neoplasm with only a few cases reported. A few neuroendocrine cells were recognized in the adjacent epithelium of the extrahepatic bile duct, suggesting that the tumor cells might be derived from them. Using immunohistochemical examination, no p53 abnormality was found. Tumor cells showed positive nuclear staining for p16, while negative for cyclin D1, suggesting that functional retinoblastoma protein (pRB) might be lost in the p16/pRB pathway, as in small cell lung cancer.