Meningioma of the external auditory canal

External auditory canal ectopic atypical meningioma: A case report and brief literature review

Meningiomas are tumours typically derived from the meningothelial cells of the arachnoid mater. They most often arise in intracranial, intraspinal, or orbital locations. Ectopic meningiomas, described as primary meningiomas with no intracranial involvement, are definitely unconventional. In fact, most of the extracranial meningiomas described in the literature, particularly in the outer ear, are effectively spreads of disease with primary intracranial localization. We describe a case of a primary external auditory canal meningioma with demonstrated absence of intracranial involvement, and we provide a full radiological, histological, immunohistochemical and molecular characterization of the lesion.

Primary external auditory canal meningioma: Case report and review of the literature

Meningiomas are tumors that arise from arachnoid cells attached to both the pia mater and the inner portion of the arachnoid. They are common intracranial tumors, representing 12-25% of intracranial neoplasms. Intracranial meningiomas can spread extracranially to involve surrounding structures, including the ear and temporal bone. Ectopic meningiomas, described as primary meningiomas with no intracranial involvement, are rare. We describe a case of a primary external auditory canal meningioma with no evidence of intracranial involvement. We present pre-operative imaging findings proving no intracranial involvement prior to surgical intervention. A literature review of this uncommon clinical entity is presented and a discussion regarding its prognosis and treatment is reviewed.

Ceruminous Neoplasms of the Ear

Ceruminous glands are modified apocrine glands located in the external auditory canal (EAC). Neoplastic lesions arising from these glands are rare in humans and constitute a major differential diagnosis for glandular neoplasms of the EAC. Due to anatomic restrictions, benign and malignant neoplasms present with similar symptoms and to some extent even comparable radiologic features, particularly when the tumors are localized. Biopsies are frequently limited by small size, fragmentation and improper anatomic and architectural orientation, thereby hampering our ability to appreciate the relationship of peripheral edges of the tumor to the surrounding tissue. Benign and malignant tumors may also have overlapping histomorphologic features, which further magnifies the challenges in accurate diagnosis and management strategies. This article summarizes the salient clinical, radiologic and histologic features of common ceruminous gland tumors, in addition to discussing features that can aid in differentiating ceruminous tumors from other EAC tumors and to distinguish benign from malignant entities.

External auditory canal meningioma: imaging features in a series of three cases

BACKGROUND

Direct extension of an intracranial meningioma to involve the temporal bone is rare. Recognised sites of origin and routes of access to the middle ear and labyrinthine apparatus have been described. Direct spread through the temporal bone to primarily involve the external auditory canal has not been widely reported in the literature.

CASE REPORTS

This paper discusses clinical and radiological findings in three cases of temporal bone meningioma presenting as masses within the external auditory canal.

CONCLUSION

Diagnosing temporal meningioma can be challenging because of its rarity and the often non-specific clinical and histological findings. It is important for both the surgeon and radiologist to be aware of the diagnosis and its related imaging findings in order to facilitate a timely diagnosis.