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We herein report a case of malignant mesothelioma from onset which developed as pleural effusion related to metastasis and later presented as an omental tumor over a 2.5 year period. A 49-year-old man developed right pleural effusion in August 1995, which was cured by thoracocentasis. One year later, his chest X-ray showed diffuse pleural thickening in August 1996, and two nodules were found in his right lung in September 1996. He was referred to the University Hospital in January 1997 because of right chest and right upper abdominal pain. The X-ray and CT of the chest revealed diffuse, irregular thickening of the right chest wall with many nodules in the lung. A CT scan of the abdomen showed three tumors in the upper abdomen. There was no history of asbestos exposure. At laparotomy, the tumors were confined to the omentum with no widespread tumor deposits. Histologically, this tumor was a malignant mesothehoma with a fibrous form mimicking fibrosarcoma. On immunohistochemical staining, the tumor cells were positive for cytokeratin and vimentin. Electron microscopy showed rare desmosomes and sparse microvilli. The patients was still undergoing chemotherapy at the time of writing.

A case of AFP-producing gastric cancer in a 66-year-old female is herein reported. The patient was admitted to the university hospital in July 1997. The laboratory data showed the serum AFP to be 2,376 ng/dl. An endoscopic examination showed a big, broadbased, polypoid tumor with an ulceration in the gastric body. She underwent a distal gastrectomy with a nodal dissection (a curative operation). The tumor was composed of three histologic types of cancer including poorly differentiated medullary adenocarcinoma, moderately differentiated tubular adenocarcinoma and hepatoid adenocarcinoma. Immunohistochemically, tubular adenocarcinoma was positive for CEA, and hepatoid adenocarcinoma was positive for AFP and hCG. After the operation, the serum AFP level decreased to the normal range. The patient has been doing well since surgery. Patients with AFP-producing gastric cancer tend to show a poor prognosis. Therefore, they should be regularly and closely followed up.

A case of anorectal amelanotic melanoma in a 72-year-old female is reported. The patient presented with several episodes of anal bleeding after defecation. Endoscopic examination showed a 1 cm-polypoid tumor with a roughly irregular surface in the right wall of the anorectum about 5 cm from the anal verge. No pigmentation was evident in the tumor. Endoscopic ultrasonography (EUS) revealed the depth of invasion to be limited to the submucosa. Although poorly differentiated adenocarcinoma was suspected by biopsy, it was difficult to classify the tumor as malignant lymphoma or malignant melanoma. Transanal simple excision of the tumor was performed. The tumor appeared homogeneously gray-whitish and was 10x17 mm in size. The tumor was finally diagnosed to be amelanotic melanoma by electron microscopy and immunohistochemistry. The depth of invasion was limited to the submucosa. The tumor was resected with 1 cm-free margins. A few decades ago, abdominoperineal resection combined with or without pelvic and bilateral inguinal lymph node dissection was recommended for the patients who had anorectal malignant melanoma with no distant metastases. However, recent studies have demonstrated that overall survival is related to the tumor size and staging of the depth of invasion, but not the extent of surgical margins. So we didn't perform additional resection. She is now living and well 11 months after operation with no evidence of recurrence of the disease. She comes to the hospital every three months.

A case of a huge abdominal leiomyosarcoma 6 years following an initial hysterectomy for a leiomyoma in a 64 year old female, is reported. The patient was referred to the Ryukyu University Hospital with a diagnosis of an abdominal tumor on June 7, 1994. She had a history of hysterectomy at age 58 for a leiomyoma. Abdominal CT scans demonstrated a large, conglomerate tumor with metastatic masses. Exploratory laparotomy revealed two large tumors with extensive peritoneal dissemination. To establish the exact nature of this abdominal tumor with pathologic examination and intend tumor reduction, the largest tumor of the omentum 24×20cm in size was resected. The pathology report was metastatic leiomyosarcoma. This condition led us to review the original uterine slides,which showed similarities with this abdominal tumor, we concluded that the abdominal tumor was a recurrent leiomyosarcoma of uterine leiomyosarcoma. In conclusion, patients with problematic uterine smooth muscle tumors should be observed closely over a long period.

A case of ruptured pseudoaneurysm of the stump of the gastroduodenal artery with treatment by transcatheter arterial embolization (TAE) in a 66-year-old man is reported. The patient underwent pancreatoduodenectomy for carcinoma of the bile duct. He developed anastomotic leakage of pancreatoienunostomy on the 7th postoperative day, and then intra-abdominal bleeding on the 25th postoperative day. Following stabilization of his general condition, emergency angiography demonstrated a rupture of pseudoaneurysm of the stump of the gastroduodenal artery which was succesfully treated by TAE., 論文

Caveolae in mesangial cells and caveolin expression in mesangial proliferative glomerulonephritis.BackgroundCaveolae are plasma membrane invaginations that have a diameter of 40 to 60 nm. Recent evidences have demonstrated that caveolae contain a variety of signal transduction molecules. Caveolin is a marker protein of caveolae and has been proposed to play a negative regulatory role in signal transduction. The aim of this study was to investigate the behavior of caveolae and caveolin in experimental glomerulonephritis, the localization of both platelet-derived growth factor (PDGF) and transforming growth factor-βbgr; (TGF-βbgr;) receptors in the caveolae membrane, and the regulation of caveolin expression in cultured mesangial cells.MethodsThe expression of caveolin-1 was examined by immunoblotting and immunohistology using anti-caveolin antibody in anti-Thy-1 nephritis. The caveolae membrane fraction of mesangial cells was isolated by sucrose gradient method and expression of PDGF receptor and TGF-βbgr; receptor were detected by immunoblotting. The effects of mitogens such as phorbol 12-myristate 13-acetate (PMA) and PDGF on the expression of caveolin-1 protein and mRNA were also examined in cultured mesangial cells.ResultsCaveolin-1 was mainly expressed in glomeruli and was significantly up-regulated in anti-Thy-1 nephritis rat kidney. In cultured mesangial cells, the membrane invaginations of caveolae were revealed by electron microscopy. PDGF receptors abounded in the caveolae membrane and rapidly changed their subcellular distribution after ligand stimulation. In contrast, TGF-βbgr; receptors abounded in the non-caveolae membrane and did not change after ligand stimulation. Decreases in caveolin-1 protein, which were associated with increases in mRNA expression after the exposure of PMA or PDGF-BB, suggested an increased turnover of caveolin-1 in mesangial cells stimulated by mitogens.ConclusionTo our knowledge, this electron microscopical study is the first to demonstrate the presence of caveolae in cultured mesangial cells. Caveolae integrate PDGF receptors, and caveolin-1 may play a role in the pathogenesis of the mesangial proliferative glomerular diseases through PDGF signaling.