Adenomatous tumors of the middle ear and mastoid have been called adenoma or adenocarcinoma. The clinical and pathologic distinction between the two has been difficult. The resultant pathologic ambiguity makes it difficult to decide whether conservative or radical management is appropriate. The Otologic Medical Group's (OMG) experience with glandular tumors of the middle ear and mastoid over the past 27 years was reviewed. Thirteen cases were found and analyzed with respect to signs and symptoms at presentation. Extensive histopathologic review with light and electron microscopy was performed on tumor specimens. Two distinctive histopathologic and clinical patterns were identified. The mixed type of tumor was always confined to the middle ear and mastoid, was commonly misdiagnosed as chronic otitis media, and rarely demonstrated otic capsule or facial nerve involvement. The papillary pattern always had extension to the petrous apex and frequently involved the middle and/or posterior cranial fossa. Papillary tumors were more frequent in females and usually involved the facial nerve. On the basis of the findings in this review as well as information from the literature, we have come to the following conclusions: 1. The correct general pathologic heading be Adenomatous Tumors of the Middle ear and Mastoid with each tumor then being subclassified into Mixed or Papillary tumor and adenocarcinoma when warranted by histology. 2. There is a high rate of local recurrence. 3. Long-term follow-up (at least 10 years) for all adenomatous tumors is necessary. 4. Primary surgical treatment is required.