De Novo Development and Progression of Endolymphatic Sac Tumour in von Hippel-Lindau Disease: An Observational Study and Literature Review

Endolymphatic sac tumors (ELST) are rare invasive lesions of the temporal bone that are commonly associated with von Hippel-Lindau disease. This report describes serial magnetic resonance imaging (MRI) and computed tomography (CT) findings over a period of 6 years in a 12-year-old patient who developed an ELST after 3.5 years surveillance for a cerebellar hemangioblastoma. A 1.5 x 8 mm tumor was identified on MRI within the endolymphatic duct when the patient presented with audiovestibular symptoms due to intralabyrinthine hemorrhage. The tumor demonstrated subsequent growth over 25 months until the patient agreed to undergo surgical resection by subtotal petrosectomy. De novo development and the natural history have been described only in six previous cases. MRI is regarded to be unreliable with respect to the ability to demonstrate an ELST in the presence of intralabyrinthine hemorrhage, with only two out of four previously reported patients demonstrating positive MRI findings. Little is known about the precise origin (endolymphatic duct versus sac), growth, and symptom correlation. This case highlights that new audiovestibular symptoms are a potential clinical clue and intralabyrinthine hemorrhage is a neuroimaging indicator for the presence of an ELST, which based on high-resolution MRI appears to originate in the endolymphatic duct rather than sac.