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The authors report here a case of lymphoepithelial cystic lesion (LECL) of unknown origin in the mediastinum, which is closely related to a signet-ring cell adenocarcinoma. A 73-year-old man presented with a mass as revealed on a chest x-ray. During surgical operation, a solid, well-circumscribed and encapsulated 9 X 9 X 8 cm tumor was isolated from the right anterior mediastinum. This tumor had neither undergone metastasis nor invaded into the surrounding tissue and lymph nodes. Light microscopy revealed the tumor to be a signet-ring cell adenocarcinoma. Clinically, the neoplasm was coupled with an elevation in serum CEA level, which promptly returned to normal values following surgical removal. Immunohistochemistry pointed out that the majority of neoplastic cells stained positive for CEA. In addition, LECL of unknown origin was distinguished at the periphery of the tumor. LECL was characterized by microcysts which were lined by columnar epithelial and surrounded by lymphoid tissue with germinal centers. Transition between the neoplastic cells and benign epithelial cells of LECL was evident, showing that the previously mentioned mediastinal adenocarcinoma may be derived from the epithelial elements of LECL. This paper discusses the histogenesis of LECL.

We describe a mucin-producing bile duct carcinoma that was resected and analyzed pathologically. Endoscopic retrograde cholangiography disclosed amorphous filling defects in the dilated extrahepatic bile duct, suggesting that a large amount of mucin was excreted from the tumor. An intraductal amorphous filling defect showed shape change at different examination times. Pathology examination revealed a papillary tumor which showed mucus production, in the right hepatic duct. The cut section of the resected specimen showed a protuberant papillary lesion, measuring 14 • 14 mm in diameter, forming a cystic mucous lake within the duct wall. Many cancer cells were also found in the mucous lake, the contents of which were strongly positive for mucin stain. The mucous lake developed laterally and communicated with the peribiliary glands, suggesting that the tumor had originated in these glands.

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We report herein the case of a 69-year-old woman in whom a hepatic tumorous necrotic lesion was discovered following transcatheter arterial embolization combined with iodized oil infusion (Lp-TAE) for a hepatoma. The lesion, which had not been evident prior to the Lp-TAE, was resected and analyzed pathologically. The portal area distribution in the necrotic lesion was the same as that in the surrounding hepatic tissue, suggesting that the lesion was derived from the nonneoplastic hepatic tissue. Moreover, extensive wall thickening and obstruction were observed in the intrahepatic portal vein and hepatic artery. These findings suggest that the lesion was a focus of hepatic infarction triggered by Lp-TAE.