SPINDLE-CELL SQUAMOUS CARCINOMA OF THE ESOPHAGUS - ANALYSIS OF PLOIDYAND TUMOR PROLIFERATIVE ACTIVITY IN A SERIES OF 13 CASES

Spindle cell squamous esophageal carcinomas are distinctive polypoid ' 'biphasic'' tumors in which the sarcoma-like phenotype usually predomi nates over the epithelial component. To biologically assess both pheno types, we compared the tumoral proliferative activity and DNA ploidy b etween the two histological components of 13 polypoid spindle cell squ amous carcinomas of the esophagus. We studied the tumoral proliferativ e index (TPI) using MIB 1 monoclonal antibody (Ki-67) and determined t he DNA histogram by image cytometry on Feulgen-stained sections. The D NA histograms were classified into four types (I to IV) according to t he degree of dispersion of the DNA. The TPI of the carcinomatous regio ns ranged from 0.20 to 0.63 (mean, 0.44) and from 0.55 to 0.85 for the sarcoma-like areas (mean, 0.68) P < .0001. In all cases, the sarcomal ike areas were aneuploid, and 37.5% of the carcinomatous regions were diploid. Also, in all instances the carcinomatous areas were of either histogram type I or II, and the sarcoma-like areas showed histograms of type II or III. We conclude that in esophageal spindle cell squamou s carcinomas the sarcoma-like phenotype differs biologically in two wa ys from the carcinomatous: (1) it has a higher TPI and (2) it has high er aneuploidy with a greater dispersion of the DNA content. We postula te that these characteristics could give a ''growth'' advantage to the sarcoma-like component of these tumors and explain its predominance o ver the carcinomatous component. HUM PATHOL 29:863-868. This is a US g overnment work. There are no restrictions on its use.