Differential grading of endolymphatic sac tumor extension by virtue of von Hippel-Lindau disease status.

Abstract

Endolymphatic sac tumors are aggressive papillary tumors of the temporal bone frequently associated with von Hippel-Lindau disease. The goal of this study was to use a newly devised classification system as a means to analyze differences between endolymphatic sac tumor extension in von Hippel-Lindau disease and non-von Hippel-Lindau disease patients. Previously reported cases of endolymphatic sac tumor and two new cases were retrospectively reviewed and assigned to a new classification system consisting of four grades based on tumor extent and location. Mean age of 103 patients without von Hippel-Lindau disease was 52.5 years, whereas in 46 patients with VHL the mean age was 31.3 years. Patients with von Hippel-Lindau disease were more likely to be female (female-to male ratio of 2:1 for von Hippel-Lindau disease patients versus 1:1 for non-von Hippel-Lindau disease patients). Symptoms consisted of hearing loss (100% [mean duration, 10 yr] for VHL patients versus 97% [mean duration, 7.8 yr] for non-von Hippel-Lindau disease patients), facial weakness (38% versus 49%), and tinnitus or vertigo (41% versus 60%). Bilateral tumors were common in von Hippel-Lindau disease patients (28% versus 1%). Tumors in von Hippel-Lindau disease patients were significantly more likely to be lower grade than tumors in non-von Hippel-Lindau disease patients (Grade I, 40% versus 25%; Grade II, 50% versus 58%; Grade III, 8% versus 14%; and Grade IV, 2% versus 4%; p < 0.05). Before 1988, there were relatively fewer Grade I (15% versus 33%) and relatively more Grade II (69% versus 47%) endolymphatic sac tumors in non-von Hippel-Lindau disease patients than after 1988. Increased usefulness of intracranial imaging since 1988 has led to the diagnosis of sporadic endolymphatic sac tumors with lower grades. Surveillance imaging in von Hippel-Lindau disease may account for the greater proportion of endolymphatic sac tumors diagnosed with lower grades. Endolymphatic sac tumors associated with a diagnosis of von Hippel-Lindau disease appear to affect a younger population of patients than non-von Hippel-Lindau disease cases and occur in women twice as often as in men when associated with von Hippel-Lindau disease. In addition, tumors are more frequently bilateral and less advanced in the von Hippel-Lindau disease patient as opposed to the non-von Hippel-Lindau disease patient.