Leiomyosarcoma of the larynx as a local relapse of squamous cell carcinoma--report of an unusual case.

Abstract

The authors report on leiomyosarcoma after previously treated squamous cell carcinoma (SCC) at the glottis. Primary tumor and relapses were investigated morphologically, immunohistochemically, and with molecular methods. The SCC was typical, but few cells showed a spindle-shaped pattern. The relapse tumor was a spindle-shaped and epitheloid tumor with the morphological and immunohistochemical appearance of leiomyosarcoma (sm-actin+, desmin+, caldesmon+, vimentin+, keratin-).The comparative genomic hybridization (CGH) revealed some gains and losses in the leiomyosarcoma. Because of altered material, the investigation failed in the primary. A fluorescence in situ hybridization (5p) focally detected 3 chromosmomal copies, corresponding to gains on 5p in CGH of leiomyosarcoma. Leiomyosarcoma after SCC is very uncommon. A connection between both seems likely in this case. Transdifferentiation, also seen in other tumors or carcinosarcomas, could be based on aberrant differentiation of a pluripotent stem cell.