Abstract

Endolymphatic sac tumor (ELST) is a very rare adenomatous tumor of the temporal bone histologically characterized by a typical papillary pattern. This tumor often shows a locally aggressive growth and recurrence despite its relatively benign histology. We report a case of endolymphatic sac tumor of the right jugular foramen in a 50 year-old male. Microscopically, the tumor was composed of uniform cuboidal to low columnar epithelial cells arranged in an arborizing papillary pattern. Under immunohistochemistry, the tumor cells were positive for cytokeratin, CD56, epithelial membrane antigen, neuron specific enolase, and vimentin.
Discussion
on the classification and histogenesis of adenomatous tumors of the middle ear and temporal bone has been active in western countries during the recent decades; however, these tumors have been very unusual in Korea. This is the second report of ELST in Korea, and consists of a discussion on related problems.

• Keywords: Endolymphatic sac;Tumor;Temporal bone;Middle ear