ARE PAPILLARY ADENOMAS ENDOLYMPHATIC SAC TUMORS

Papillary adenomas of the temporal bone have been considered as origin ating from the endolymphatic sac. The radiologic, surgical, and pathol ogic findings in a patient suffering from von Hippel-Lindau disease wi th bilateral papillary adenomas of the temporal bone cast some doubt o n this site of origin. Radiologically, the center of tumor growth was at the top of the jugular bulb. lntraoperatively,the tumor was found t o have reached the lateral wall of the endolymphatic sac, but the lume n was tumor-free Both ciliated and nonciliated tumor cells were found in the resected tumor, resembling the ultrastructure of normal epithel ial lining in the human mastoid. A strong positive immunohistochemical reaction for keratin and negative reactions for vimentin, glial fibri llary acidic protein, and S-100 protein in the tumor tissue of this pa tient are typical for middle ear mucosa. Therefore, the described papi llary adenoma originated from the mucosa of the pneumatic spaces surro unding the jugular bulb, and the theory that the endolymphatic sac is the origin of all papillary-cystic tumors (adenocarcinomas) should be questioned.