Invasive verrucous carcinoma: a temporal bone histopathology report.

Only nine cases of primary verrucous carcinoma of the temporal bone have been reported in the English literature. We describe histopathologic findings in a 78-year-old man dying of intracranial complications of primary verrucous carcinoma of the external auditory canal. Following autopsy the temporal bone was prepared for light microscopic examination. The temporal bone was serially sectioned horizontally after fixation, decalcification, and embedding, and each 10th section was stained with hematoxylin and eosin and examined by light microscopy. The carcinoma originated from the external auditory canal, infiltrating the mastoid cavity, the middle ear, tissue adjacent to the internal carotid artery, and the posterior cranial fossa, where it invaded the right cerebellum and produced an abscess. The labyrinth and internal auditory canal were not infiltrated. Metastasis to lymph nodes or distant sites was not identified. In the present case, the verrucous carcinoma originating from the external auditory canal extended into the posterior cranial fossa, while it did not invade the membranous labyrinth.