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Tumours of the Temporal Bone
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
Marcus Atlas, Noweed Ahmad, Peter O’Sullivan
The glandular components of the external auditory canal consist of sebaceous glands and modified apocrine glands, called ‘ceruminous glands’. Previously, glandular tumours of the external auditory canal had been classified under the umbrella term of ceruminoma, but this term is non-specific and should not be used without qualification. There has been some confusion in the literature with no agreed system of nomenclature for these tumours14 but classification of glandular tumours of the external ear by Wetli et al. 15 is relatively less complicated: ceruminous adenomapleomorphic adenomaadenoid cystic carcinomaceruminous adenocarcinoma.
Pleomorphic adenoma of the external auditory canal: A common tumour in an uncommon site
Published in Acta Oto-Laryngologica Case Reports, 2020
S. O. Ayodele, O. A. Afolabi, O. O. Folaranmi, F. E. Ologe
According to the WHO classification, the ceruminous gland tumours are broadly classified into benign and malignant. The benign ceruminal gland tumours include adenoma, chondroid syringoma (pleomorphic adenoma) and syringocystadenoma papilliferum. While, the malignant ceruminal gland tumours include adenocarcinoma, adenoid cystic carcinoma, and mucoepidermoid carcinoma [7]. On the other hand, Saito et al. [8] and Wetli et al. [9] suggested that tumours of ceruminal gland origin should be classified into four categories: adenoma, pleomorphic adenoma, adenocarcinoma, and adenoid cystic carcinoma. This widely accepted classification system clearly distinguishes two benign (ceruminous adenoma and pleomorphic adenoma) and two malignant (ceruminous adenocarcinoma and adenoid cystic carcinoma) categories [8]. Regardless of which classification system is used, it is clear that malignant tumours commonly arise from the external auditory canal and that pleomorphic adenoma of the external auditory canal is relatively rare [7]. Similar to the histological diagnosis made in this case report, the term ‘pleomorphic’ was chosen to describe this tumour, because it possesses morphologic diversity with both epithelial and mesenchymal component in various proportions [2]: it is a biphasic tumour and characterized by admixture of polygonal epithelial and spindle shaped myoepithelial cells in a variable stromal background that may be mucoid, myxoid chondroid, or hyaline [10]. Pleomorphic adenoma has been classified as a naturally slow growing benign tumour, but have the capacity to grow into large proportions and may undergo malignant transformation [1,6]. The incidence of malignant transformation has been cited as 6%, and the most important factor which determines this tendency is the length of the time for which the tumour has been present [1].