ENDOLYMPHATIC SAC TUMORS

This review article surveys clinical and pathological literature on en dolymphatic sac tumours (ELST) and summarizes characteristics that des cribe the entity, ELST are rare neuroectodermal neoplasms in the petro us bone, originating from inner ear structures. They can be encountere d sporadically or in von Hippel-Lindau disease. The most prominent sym ptom is sensorineural deafness. Historically, nomenclature of invasive adenoid tumours in the petrous bone has been divergent, the term papi llary adenocarcinoma used most frequently. Histologically, they have a follicular or papillary and adenoid pattern that can be easily confus ed with various other neoplastic conditions including metastatic carci noma. It remains to be verified whether similar tumours (papillary ade nocarcinomas) can originate from the middle ear. Middle ear adenomas h ave a similar appearance but probably originate from neural crest cell s in the middle ear. ELST can express a variety of epitopes (including cytokeratin and neuroectodermal markers) which can be detected immuno histochemically, In cases of von Hippel-Lindau disease the cerebellopo ntine angle should be included in routine radiological examinations to detect ELST before the tumours lead to deafness, In apparently sporad ic cases of ELST, genetic testing for von Hippel-Lindau disease should be considered. Correct distinction of ELST from metastatic carcinoma prevents futile searches for unknown primary tumours.