Head & Neck, Endolymphatic sac tumour

Endolymphatic sac tumour is an epithelial tumour arising within the endolymphatic sac/duct and is highly associated with von Hippel-Lindau syndrome. It generally presents in adulthood with unilateral hearing loss. Microscopically, the tumour often demonstrates bone invasion and shows a papillary architecture with a single layer of low cuboidal to columnar epithelial cells. The cytoplasm is clear to granular eosinophilic; there are indistinct cell borders; nuclei are small, round, and hyperchromatic. Prognosis is generally good although complete surgical resection is often difficult to achieve.