Timothy C. Hain, MD
Page last modified: February 1, 2017
Endolymphatic sac tumors are very rare tumors (adenomas) arising at the interface between the posterior fossa and the petrous temporal bone.
Hearing loss, vestibular dysfunction, facial weakness, and facial numbness or paresthesia. These tumors may be indentified on mastoid exploration for shunt placement. Symptoms typically progress over a period of several years.
|Hemangioblastoma lesions in spinal cord and cerebellum in patient with Von Hippel Lindau disease, who also had an endolymphatic sac tumor.|
Some of these tumors are associated with von Hippel Lindau disease (VHL), which is characterized by angiomatosis of the retina and cerebellum and similar lesions in other organs. VHL is an inherited disorder associated with cysts in the kidneys, pancreas and male genital tract. There is also an increased risk of developing clear-cell renal cell carcinoma as well as pheochormocytoma. About 10% of persons with VHL develop endolymphatic sac tumors. The genetic defect is in the VHL gene which is a tumor supressor gene. VHL is inherited in an autosomal dominant fashion, but two copies of the mutation are needed to cause the disorder. A second mutation can occur during a person's lifetime in a particular cell, which allows tumors and cysts to develop.
The Herman, Von Hippel, wrote two seminal articles regarding one of his patients and in 1921 he published an autopsy of this patient which revealed central nervous system tumors including a tumor located in the temporal bone (Corrales and Mudrey, 2017). In 1988, Eby et al described a case series of petrous apex tumors in which one with von Hippel-Lindau disease developed bilateral endolymphatic sac tumors. Thus the case material concerning these tumors is very limited.
Damage is due to destruction of the ear and involvement of close neurological structures.
The otoscopic examination is usually normal.
Radiological studies show temporal bone destruction with a tumor centered in the retrolabyrinthine petrous bone above the jugular bulb at the interface between the posterior fossa dura and petrous temporal bone. The tumor may extend into the CP angle.
CT scans show a tumor with bone destruction. MRI scans of large tumors show hyper and hypointensity on both T1 and T2 images with strong post-gadolinium enhancement. Small tumors confined to the endolymphatic sac may be hard to see however.
Tumors may be as large as 4-6 cm. These tumors do not metastasize.
These are agressive tumors, due to local invasion. The treatment is mainly surgical with total resection, and post-operative radiation.