Clinicopathological studies of esophageal carcinosarcoma: Analyses of its morphological characteristics using endoscopic, histological, and immunohistochemical procedures

Background and Study Aims: Carcinosarcoma of the esophagus is a rare malign ant neoplasm consisting of both carcinomatous and sarcomatous components, w hich characteristically forms polypoid tumors. Patients and Methods: Seven carcinosarcomas were analyzed using endoscopic, histological, and immunohistochemical procedures. Endoscopically, six of t he seven lesions were found to be of the protruding type, while the other o ne was an ulcerating tumor. Results: In all seven cases, the carcinomatous component consisted of diffe rentiated squamous cell carcinoma, and the sarcomatous component was spindl e cell carcinoma. Histological analyses demonstrated that the majority of t he protruding tumors consisted of the sarcomatous component, while the ulce rating tumor mainly consisted of squamous cell carcinoma. The Ki-67 (MIB-1) labeling index (LI) of the carcinomatous component (28.2%) did not differ significantly from that of the sarcomatous component (25.5%). The sarcomato us component showed abundant expression of type IV collagen and laminin, Conclusions: It is conceivable that the carcinomatous and sarcomatous compo nents grow separately from the early stage of the tumors, and that the sarc omatous component forms a protruding tumor mass because it has abundant str oma positive for type IV collagen and laminin.