Should endolymphatic sac tumors be considered part of the von Hippel-Lindau complex? Pathology case report

Von Hippel-Lindau (vHL) disease is an inherited disorder characterized by numerous cystic and solid neoplasms. Because of the recent identification of the vHL gene, other investigators have demonstrated genetic mutations in this gene in several of the neoplasms associated with the disease. We describe a patient with an endolymphatic sac (ELS) tumor and vHL disease. The purpose of this study was to identify a similar genetic mutation within the vHL gene of the ELS tumor.

Using the patient's archival pathological slides, neoplastic cells were microdissected to yield a purely neoplastic cell population. The deoxyribonucleic acid of these cells was then extracted and amplified via polymerase chain reaction. After sufficient amplification, the specimen was analyzed on a single-strand conformation polymorphism gel system to detect putative changes in the base sequence.

Single-strand conformation polymorphism gel system analysis yielded two bands representing the two single strands of deoxyribonucleic acid that were amplified. The upper band of the specimen was shifted down (compared with controls), representing a conformational change as a result of genetic mutation.

ELS tumors are uncommon, and, to our knowledge, only seven cases associated with vHL disease have been reported in the literature. Although this association has been previously mentioned, no definitive studies have linked the two together. We report the eighth case of ELS tumor and vHL disease. We have demonstrated through molecular biological techniques, that, in our patient's tumor, a genetic mutation occurred, and that this mutation is similar to mutations previously reported in other neoplasms associated with vHL. We therefore suggest that ELS tumors be considered among the neoplasms associated with vHL.