Adenocarcinoma and adenoma of the middle ear.

Primary middle ear glandular tumors of the adenocarcinoma and adenoma types are rare. The terminology used in describing them is quite varied. Some investigators presume that a distinct recognizable group of these tumors are benign, but because of the rarity of the lesions, such conclusions have been difficult to verify. We review the literature of these lesions and report 11 additional cases. The course was documented in 25 cases in the literature; 20 of these were reported to be benign over periods of follow-up from 1 month to 10 years, and 5 were fatal. Among our patients, 5 had a benign course, 3 died of causes related to the tumor, and 3 had persistence of their lesion and substantial consequent morbidity. We emphasize the slow growth and elusive nature of these lesions. Histologic evidence of mitoses, roentgenologic evidence of bony destruction, and cranial nerve involvement were factors consistent with a poor prognosis. The origin of these tumors may vary. A similarity to paragangliomas is noted. The ultimate course of these tumors cannot always be predicted from the histologic appearance. Early surgical removal appears to be the most successful therapy. Three of the 4 types of glandular tumors of the external ear canal described by Wetli, et al, can be found in the middle ear: adenoma, adenocarcinoma, and adenoid cystic carcinoma. In addition, several other types of glandular lesions can occur in the middle ear--the "choristomas," mucoepidermoid carcinomas, and what we believe to be a variant of paragangliomas. The adenoid cystic tumors are well described in the literature and will not be discussed here. We reviewed cases of the adenoma and adenocarcinoma types, some of which bore a resemblance to the paragangliomas.