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.