Adenomatous Tumors of the Middle Ear: A Literature Review

Abstract

Introduction Neuroendocrine adenomas of the middle ear (NAME) are uncommon causes of middle ear masses. Mostly limited to case reports and small series, the literature is poor in providing an overall assessment of these tumors. Objective To review the current literature about all aspects of the disease, including its etiology, clinical manifestations, diagnosis, and treatment. Data Synthesis The pathogenesis of adenomatous tumors of the middle ear is not clear yet. One potential explanation is that an undifferentiated pluripotent endodermal stem cell may still be present in the middle ear mucosal surface, and may be the origin of the tumors. It typically appears as a nonspecific retrotympanic mass. The average age of onset for the disease is the fifth decade, and the most common clinical symptom is conductive hearing loss. Malign behavior is rare. There are numerous differential diagnoses of NAME. The final diagnosis depends on microscopic findings. The preoperative evaluation should include the use of computed tomography and magnetic resonance imaging. The adjunctive therapy of middle ear adenomatous tumors with radiotherapy, chemotherapy or somatostatin analogs is generally not recommended. Conclusion There is still much debate on pathogenesis and classification of NAME. Saliba's classification is currently the most complete and preferable one. Aggressive surgical procedure with ossicular chain excision is the gold standard treatment. Follow-up with physical and radiological exams is mandatory, particularly if the first procedure was conservative, without the removal of the encased ossicles.

Neuroendocrine Neoplasms of the Ear

“…Moreover, the glandular features and the keratin positivity seen typically in NENE are absent in Jugulotympanic paraganglioma. By IHC, S100 is negative in NENE but positive in Jugulotympanic paraganglioma in sustentacular pattern [6]. The histology of endolymphatic sac papillary tumor with the presence of papillary formations and its aggressive clinical course with bone invasion and intracranial extension differ markedly from those of NENE [3].…”

“…Bone expansion within the middle ear space is common, associated with bone remolding and encasement of the ossicles, but usually without bone destruction [4]. MRI may be useful in cases with extension to the posterior fossa [6]. On MRI, tumors are isointense to hyperintense, relative to white matters on T1-weighted images and extensively enhanced by gadolinium on T2-weighted images [6].…”

“…MRI may be useful in cases with extension to the posterior fossa [6]. On MRI, tumors are isointense to hyperintense, relative to white matters on T1-weighted images and extensively enhanced by gadolinium on T2-weighted images [6]. The tumor radiographic findings are important consideration in the differential diagnosis.…”

“…Compared to the primary and metastatic adenocarcinomas of the ear, NENE lack the aggressive histologic features (pleomorphism, necrosis, and increased mitoses) and invasion of bone and adjacent structures that are usually seen in these tumors [10]. Rhabdomyosarcoma (including alveolar rhabdomyosarcoma) seldom occurs the ear [6]; alveolar rhabdomyosarcoma can rarely show an aberrant epithelial and neuroendocrine expression by IHC. However, the morphologic features of RMS along with the positive staining for the muscle markers distinguish this tumor from NENE [2].…”

Recurrent Adenomatous Neuroendocrine Tumor of the Middle Ear: A Diagnostic Challenge

“…Definite diagnosis relies on combined histopathology and immunohistochemistry. The authors discuss the controversial terminology of these tumors based on different degrees of glandular or neuroendocrine differentiation [6, 7, 12, 13].…”