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 malignant neoplasm consisting of both carcinomatous and sarcomatous components, which characteristically forms polypoid tumors.

PATIENTS AND METHODS: Seven carcinosarcomas were analyzed using endoscopic, histological, and immunohistochemical procedures. Endoscopically, six of the seven lesions were found to be of the protruding type, while the other one was an ulcerating tumor.

RESULTS: In all seven cases, the carcinomatous component consisted of differentiated squamous cell carcinoma, and the sarcomatous component was spindle cell carcinoma. Histological analyses demonstrated that the majority of the protruding tumors consisted of the sarcomatous component, while the ulcerating 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 sarcomatous component showed abundant expression of type IV collagen and laminin.

CONCLUSIONS: It is conceivable that the carcinomatous and sarcomatous components grow separately from the early stage of the tumors, and that the sarcomatous component forms a protruding tumor mass because it has abundant stroma positive for type IV collagen and laminin.