小细胞恶性间皮瘤的超微结构观察

应用电镜观察小细胞恶性间皮瘤的超微结构特点，对5例福尔马林固定后、经光镜及免疫组化检查过的胸膜及腹膜肿瘤标本进行常规电镜标本制备及电镜观察。超微观察显示肿瘤细胞呈小圆形及小梭形。5例均见腺腔样结构、细长微绒毛、紧密连接及发育良好的桥粒。较长的微绒毛长度与直径之比为13：1。见不连续基板（2例）、胞质内张力丝（2例）及微丝（4例），2例同时见核旁分布的球形微丝小体。结论：细长微绒毛是包括低分化小细胞恶性问皮瘤在内的恶性间皮瘤的特征性超微结构。电镜观察对确定小细胞恶性问皮瘤的病理诊断及鉴别诊断有帮助。

Ultrastructural characteristics of small cell malignant mesothelioma

To study the ultrastructural characteristics of small cell malignant mesothelioma,the formalin-fixed specimens from 5 cases pleural and peritoneal tumors were examined by light microscopy,immunohistochemistry,and transmission electron microscopy.Ultrastructurally,the tumor cells were of small round and small spindle in shape.All 5 cases showed the presence of glandular lumen-like structure with long and slender microvilli,tight junctions,and well developed desmosomes.The longest microvillus had a length: diameter ratio of 13:1.The interrupted basal lamina(2 cases),intracytoplasmic tonofilaments(2 cases),and microfilaments(4 cases) were seen.The tumor cells of 2 cases possessed paranuclear distributed globular filamentous bodies.The long and slender microvilli are the ultrastructural characteristics of malignant mesotheliomas including low differentiated small cell malignant mesothelioma.Electron microscopic examination is helpful in the pathological diagnosis and differential diagnosis of small cell malignant mesothelioma.