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

Objective: 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 diffferences between endolymphatic sac tumor extension in von Hippel-Lindau disease and non-von Hippel-Lindau disease patients. Methods: 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. Results: Mean age of 103 patients without von Hippel-Lindau disease was 52.5 years, whereas in 46 patients with VHL the A 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. Conclusions: 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.