Middle ear glandular neoplasms: adenoma, carcinoma or adenoma with neuroendocrine differentiation: a case series

Abstract

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.

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.

Figure 1

Axial (A) and coronal (B) views of a mastoid computerized tomography (CT) scan showing a right mastoid and middle ear opacity. The tympanic membrane is pressed laterally by the mass.

Figure 2

Middle ear adenoma. Tumor composed of small glands lined by a single layer of uniform cuboidal cells with an intraluminal eosinophilic secretion. No mitotic activity or necrosis (original magnification 400X).

Figure 3

Middle ear adenoma. Minor foci of tumor composed of sheets of loosely cohesive cells with moderate to abundant eosinophilic cytoplasm and eccentrically placed nuclei (plasmacytoid morphology) (original magnification 200X).

Figure 4

Middle ear adenoma. Immunohistochemical stains for synaptophysin (A) and chromogranin (B) show strong positivity within tumor cells.

Figure 5

Axial (A) and coronal (B) T2-weighted magnetic resonance imaging (MRI) scan one-year post-operative excision showing no sign of recurrence.