Primary carcinosarcoma of the helix of the ear.

We report our histologic and immunohistochemical findings in a rare case of cutaneous carcinosarcoma involving the helix of the ear. The tumor exhibited cellular features of both basal cell and squamous cell carcinoma and a malignant mesenchymal component that was consistent with malignant fibrous histiocytoma. The epithelial component exhibited a positive immunohistochemical reaction to cytokeratin and a negative reaction to vimentin, whereas the mesenchymal component showed a positive immunohistochemical reaction to vimentin and a negative reaction to cytokeratin. To the best of our knowledge, this is only the third reported case of a carcinosarcoma of the ear and the second case in which it developed on the helix.