True carcinosarcoma of the larynx.

A case of carcinosarcoma of the larynx and pyriform sinus with sarcomatous and epithelial malignant components is described in a 68-year-old male. The primary site was composed of spindle-shaped malignant mesenchymal cells with osteosarcomatous and chondrosarcomatous differentiation intermingled with areas of well differentiated squamous cell carcinoma, tubular and papillary adenocarcinoma, and trabecular neuroendocrine carcinoma. The metastatic lymph node showed squamous cell carcinoma and chondrosarcoma. Immunohistochemical studies showed that keratin was present in epithelia cells and negative in sarcoma, whereas vimentin and S-100 protein were present in sarcoma, but negative in carcinoma. Neuron-specific enolase was present in the neuroendocrine part of the tumour.