Giant intracranial endolymphatic sac tumor (ELST). Case presentation and histogenetic considerations.

We present a giant tumor of the skull base compressing the brain in a 40-years-old man. The tumor was policystic at imaging. Its histopathology, immunohistochemical profile and long evolution suggest an endolymphatic sac tumor (ELST), a rare case of neoplasia. Since the patient had multiple otolaryngological procedures in his medical history, a possible traumatic pathogenesis could be suspected. On the other way, some immunohistochemical aspects found in our case may imply a histogenesis divergent from that currently accepted. This could be from either the organ of Corti or some local cells that generate a resemblance with a systemic tumor, the so-called benign mesothelioma. Further studies are needed in order to clarify this topic.