RECLASSIFICATION OF AGGRESSIVE ADENOMATOUS MASTOID NEOPLASMS AS ENDOLYMPHATIC SAC TUMORS

The emerging concept that aggressive adenomatous tumors of the tempora l bone arise from the endolymphatic sac and constitute a distinct clin icopathologic entity merits wider recognition. These tumors share a co mmon clinical pattern and exhibit consistent imaging and histopatholog ic features. Endolymphatic sac tumors (ELSTs) have been mistaken for o ther neoplasms such as paragangliomas, adenomatous tumors of mixed his tology, ceruminomas, and choroid plexus papillomas. A review of the li terature shows similarities among case studies of these aggressive ade nomatous lesions. An analysis of the data supports the endolymphatic s ac as an origin for these tumors. This report also presents an additio nal case of a less differentiated variant of this rare but important c linicopathologic entity.