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An adenomatous tumor of the middle ear was examined by light microscopy, ultrastructural and immunocytochemical technics. It demonstrated the typical histologic growth pattern and featured ultrastructural evidence of glandular differentiation with two distinct types of secretory granules, apically oriented mucus granules and basally located uniformly condensed neurosecretory granules. In support of its neuroendocrine differentiation was the detection of neuron-specific enolase and positive reaction with monoclonal antibody to chromogranin. These findings are compared with previously reported cases and with middle ear mucosa. It is suggested that this bidirectional differentiation is analogous to that seen in other endodermally derived neuroendocrine tumors.

Seven patients with middle ear adenomas (MEA) are presented. MEA are cytologically stereotyped neoplasms with a spectrum of architectural patterns. All tumors were composed of uniform, round, or ovoid cells that resembled normal middle ear epithelium. The histologic patterns varied from tumor to tumor and within a single lesion. Broad sheets of tightly packed cells were commonly present, but glandular and cribriform areas were also frequent. Complex, interdigitating trabeculae, rows of individual cells, and dissociated cells were sometimes seen. Grimelius argyrophil stains were focally positive in three of five stained tumors, but Churukian-Schenk argyrophil preparations demonstrated only rare positive cells in two of these cases. Lysozyme was demonstrable immunohistochemically in each tumor. Lysozyme is present in normal middle ear epithelium and may be a useful marker for MEA, since the tumor is apparently derived from these cells. The clinical features of the seven cases that we report are combined with 44 MEA from the literature. MEA seldom recurs after excision and very rarely invades bone. No patient died of disease. The clinical and histologic distinction of these tumors from plasmacytoma, paraganglioma, ceruminoma, carcinoid tumor, and papillary carcinoma is discussed.

Middle ear adenoma (MEA) is a distinctive, rare entity that appears to be derived from the lining epithelium of the middle ear mucosa. We report four cases of MEA displaying the typical histologic growth pattern. Two distinct tumor cell immunophenotypes were identified in all cases; the first type exhibited positivity with anti-epithelial membrane antigen and anti-keratin antibodies, and the second type showed immunoreactivity with anti-keratin, anti-vimentin, and anti-neuron-specific enolase antibodies. Ultrastructural studies revealed bidirectional mucinous and neuroendocrine differentiation, demonstrated by the presence of two distinct cell types containing apically located mucous granules and basally concentrated neuroendocrine granules, respectively. The presence of neuroendocrine differentiation was supported by the immunohistochemical detection of vasoactive intestinal polypeptide in the tumor cells in one case and neuron-specific enolase in three cases. These findings suggest that the potential for mixed mucinous/neuroendocrine differentiation described in other endodermally derived tumors also exists in middle ear mucosa. We also believe that the rare lesions diagnosed as primary carcinoid tumors of the middle ear might in fact be MEA with predominant or only neuroendocrine differentiation. The clinical course of our four cases and our review of the pertinent literature confirm the benign nature of MEA and indicate that these tumors should be treated by complete local excision without additional therapy. Am J Surg Pathol

A case of glandular middle ear tumor of salivary tissue or salivary like tissue is presented. The rarity of this type of middle ear tumor caused initial difficulty in arriving at a diagnosis at the time of surgery. The current opinion in the literature as to the etiology of such tumors is divided among ceruminous glands, middle ear mucosal metaplasia and ectopic salivary gland tissue. Experience with more additional cases will help to establish etiological concept and will increase our knowledge as to treatment and prognosis.

A 56-year-old woman presented with unilateral tinnitus and hearing loss for 18 months. A middle ear mass was detected clinically. At operation, the tumour was found to have eroded the stapes. The light and electron microscopic features of the tumour were those of a middle ear adenoma. This rare benign tumour has an excellent prognosis. Erosion of an ossicle has not been previously associated with this tumour.Benign adenomatous tumours arising from middle ear mucosa are rare (Mills and Fechner, 1984). The term adenoma of middle ear was proposed by Hyams and Michales (1976), and their review of 20 cases emphasized the benign behaviour of these tumours. We report a case of middle ear adenoma in which ossicular erosion occurred.

Primary adenomatous tumors of the middle ear are preponderantly benign, resectable lesions and arise from the mucosa (adenomas) or salivary tissue (choristomas). Malignant variants are ill defined, are not characterized histologically, and represent less than 10% of the adenomatous tumors. Their presence may be signaled clinically by facial nerve paralysis, invasion of bone, and chronic otorrhea.

A 29-year-old woman had a middle-ear mass that resulted in hearing loss and seventh-nerve palsy. The tumor invaded the petrous bone, the mastoid, at least one semicircular canal, and then extended into the posterior fossa. Microscopically, it consisted of complex, interdigitating papillae lined by uniform, cuboidal to low columnar cells. The cells resembled the epithelium of the normal middle ear and middle-ear adenoma, but the papillary architecture distinguished this neoplasm from the latter, nonpapillary tumors. Papillary middle-ear tumors are locally invasive. We propose the term "aggressive papillary middle-ear tumor" (APMET). Nine other examples of APMET have been reported under various diagnostic terms. All have been locally destructive with frequent intracranial invasion. Although none of the tumors has metastasized, one patient died of uncontrolled local disease. For this reason, APMET must be distinguished from nonpapillary middle-ear tumors.

Three cases of middle ear and mastoid neoplasms are reported as “adenomatous tumors” since in their search of the literature the authors did not find any previously described lesions with a similar histologic appearance and benign biologic behavior. Microscopically, all three tumors are similarly composed of solid cords and nests of closely-packed small cells having an epithelial appearance. Two distinct cell types are present: cuboidal cells, arranged in a rudimentary gland-like pattern, and angular cells forming irregular nests with no distinct pattern. All three tumors developed in patients in their 20′s, over a period of months with minimal symptoms; yet in all of the lesions the tympanic membrane was intact at the time of initial examination. None of the neoplasms was diagnosed preoperatively, and, once removed, all three tumors were pathologic enigmas and therapeutic problems in view of the initial and subsequent consultant pathologic opinions; nevertheless, total local excision with preservation of the tympanic membrane would appear to be safe treatment in these cases. The term “adenomatous tumor” is applied to these three neoplasms because: 1. a true glandular epithelial origin warranting the term adenoma or adenocarcinoma cannot be proven; and 2. the biologic behavior and prognosis is not necessarily reflected by the histologic appearance. A more specific term reflecting the origin and behavior of these tumors does not appear possible without the study of further cases.

Benign adenoma of the middle ear emerged as a distinct entity following a review of 20 cases as reported from the Armed Forces Institute of Pathology in 1976. We report 4 additional cases and note that the pathologic diagnosis is not so clear cut. Benign primary adenoma may be confused with adenocarcinoma, ceruminoma, and glomus tumor. The otologic surgeon must take a hard look at the clinical signs and symptoms to determine if they are compatible with the diagnosis of primary middle ear adenoma. While middle ear adenoma has recently been implicated as a cause of facial paralysis (including a case herein), bone destruction should never be found in concert with this neoplasm.

An adenomatous neoplasm from the middle ear was studied. Two distinct groups of cells were present. Electron microscopy suggested that one group was epithelial and the other neuroendocrine in origin. The features supported the hypothesis that such tumors arise from middle ear mucosa.

This presentation is a study of the pathogenesis, clinical behaviour and therapeutic response of 20 cases of a primary adenomatous neoplasm confined to the middle ear cleft. The investigation supported origin of the tumour from the middle ear mucosal epithelium. Clinical behaviour was that of a benign, localized, non-metastasizing neoplasm. Simple localized surgical removal of the tumour afforded an excellent prognosis in all cases. The designation of the tumour entity as adenoma of middle ear is proposed.

Introduction Middle ear glandular neoplasms are infrequent causes of a middle ear mass. They can have exocrine and/or neuroendocrine differentiation. It is currently thought that these tumors are indistinguishable each from another. Herein, we present a new case of a middle ear glandular neoplasm. Our objective is to review all cases described in the literature in order to identify the clinical features, the gross pathology, the histopathology, the immunohistochemistry, to discuss the differential diagnosis, the treatment, the rate of recurrence, the follow-up, the incidence of metastasis, the prognosis and to present a new classification of middle ear glandular neoplasm. Case presentation Methods We performed a MEDLINE database search for MEA-related articles published between 1950 and March 2008. The information from the reports was analyzed. Results Ninety-four patients with a middle ear adenoma are included in this report. We uncovered 75 patients with a carcinoid tumor and 19 patients with a middle ear adenoma diagnosis; the most common presenting symptom was a conductive hearing loss. Middle ear adenomas are lesions that are typically white, gray or reddish brown. They are grossly vascular and well circumscribed, but not encapsulated, and can entrap and destroy the ossicles. Histologically, the cuboidal to low columnar cells are arranged in a solid, trabecular or glandular architecture. The tumor's cells are immunohistochemically positive for a variety of keratin antibodies and most of them are also positive for neuroendocrine markers. Surgical excision is the treatment of choice. Local recurrence following complete excision is quite uncommon and metastases are rare. Conclusions Our study and the review of the literature showed adenomas and carcinoid tumors of the middle ear to be essentially indistinguishable benign tumors with metastatic potential. Based on the presence or absence of immunohistochemical markers and metastasis, we have classified these lesions into three types. Complete surgical treatment is recommended with an indefinite follow-up for possible recurrence.