Update From the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Tumours of the Ear

Abstract

The 2017 fourth edition of the World Health Organization Classification of Tumours, specifically as it relates to the ear (Chap. 9), has several changes. Importantly, the number of entities has been significantly reduced by omitting tumors or lesions if they do not occur exclusively or predominantly at this site or if they are discussed in detail elsewhere in the book. These entities include: embryonal rhabdomyosarcoma, osteoma, exostosis, angiolymphoid hyperplasia with eosinophilia, Schneiderian papilloma, inverted papilloma, lipoma of the internal auditory canal, hemangioma, hematolymphoid tumors, and secondary tumors. Paraganglioma was included in the neck chapter. New entries include otosclerosis and cholesteatoma, while refinements to nomenclature, classification and criteria were incorporated into the ceruminous gland tumors and epithelial tumors of the middle and inner ear. Specifically, the middle and inner ear were combined, as practical limitations of origin and imaging make a definitive separation artificial. The classification reflects the state of current understanding for these uncommon entities, with this update only highlighting selected entities that were the most significantly changed.

Keywords: Carcinoma, squamous cell; Cholesteatoma; Ear; Ear, middle; Hearing loss; Otosclerosis; Temporal bone; Tumor; WHO.

Fig. 1

A clinical photograph showing an ulcerated mass completely occluding the external auditory canal (courtesy Dr. Carsten Palme)

Fig. 2

a A well differentiated squamous cell carcinoma, showing a pavemented growth of squamous cells. Mitoses are noted. b A spindle cell SCC is a more biologically aggressive variant in the EAC

Fig. 3

A coronal MRI T1 weighted fat suppressed image shows a large tumor (arrow) expanding into the bony EAC, but separate and distinct from the parotid gland

Fig. 4

Ceruminous adenocarcinoma. a A widely infiltrative tumor, showing a mixed glandular architecture. b The biphasic appearance is noted, with basal cells still present in this ceruminous adenocarcinoma. Mitotic figures (arrow) are increased. c An adenoid cystic ceruminous adenocarcinoma is noted adjacent to uninvolved ceruminous glands (left). d The classical histologic features of adenoid cystic carcinoma, including clefting, cribriform architecture, and glycosaminoglycan material, are seen

Fig. 5

Ceruminous adenoma. a The glandular to solid architecture of a ceruminous adenoma is noted below the intact squamous epithelium. b Yellow-bodies are noted with the cytoplasm of this ceruminous adenoma. c The biphasic basal and luminal components are easily seen in this adenoma. Note the yellow–brown ceroid granules

Fig. 6

a Ceruminous pleomorphic adenoma, shows ceruminous differentiation in the epithelial component, blended with a myxochondroid matrix. b A ceruminous syringocystadenoma papilliferum with numerous papillary projects and plasma cells

Fig. 7

Aggressive papillary tumor. The tumor shows complex papillary structures (a), lined by neoplastic cells that are cuboidal to columnar, with limited pleomorphism (b)

Fig. 8

Endolymphatic sac tumor. a Broad papillary structures expanding into bone. b The neoplastic cells are columnar, with lightly eosinophilic cytoplasm surrounding oval nuclei. Note the luminal secretions

Fig. 9

Intraoperative image of the immobilized stapes bone seen in otosclerosis (courtesy Dr. Gabriel Calzada)

Fig. 10

The left part of the image shows the cochlea, with a tumor-like mass of immature trabecular bone expanding the otic capsule, immediately at the point of the stapes joint (courtesy Dr. Ann Sandison)

Fig. 11

Cholesteatoma. a A high resolution computed tomography scan shows opacification of the middle ear, contained by an intact tympanic membrane (arrow). b Otoscopic view of a left ear acquired cholesteatoma with ear drum rupture and keratinous debris (courtesy Dr. Ann Sandison). c Histology shows a squamous epithelium associated with inflammation and keratinaceous debris

Fig. 12

Cholesteatoma. a Thin squamous epithelium with no rete, prominent granular layer and luminal keratin debris. Inflammation and foreign body giant-cell reaction is noted. b This cholesteatoma is associated with a middle ear adenoma, a concurrent finding