Von Hippel-Lindau disease

von Hippel-Lindau (VHL) disease is an inheritable condition with an incidence of 1 in 36000 live births. Individuals with VHL develop benign and malignant tumors including retinal and central nervous system hemangioblastomas, clear cell renal cell carcinomas (RCC), pheochromocytomas, pancreatic neuroendocrine tumors and endolymphatic sac tumors (ELSTs). VHL is caused by germline loss of function of the VHL gene on one allele at chromosome 3p25-26. A somatic "second hit" event leads to the loss of the other allele and tumor formation. Loss of VHL function in cells leads to increased expression and stabilization of hypoxia inducible factor (HIF). VHL protein/HIF pathway has been implicated in tumorigenesis for hemangioblastomas, RCC and other VHL tumors. Clinical examination, imaging, and genetic testing for VHL mutations confirm VHL disease. Management of VHL disease largely consists of surgical resection of symptomatic tumors (hemangioblastomas), tumors prone to metastasize (RCC larger than 3cm), or tumors causing hormonal symptoms (pheochromocytomas). Despite advances in early diagnosis and management of VHL disease, life expectancy for VHL patients remains low at 40-52 years. Secondary effects from VHL manifestations are mitigated by routine surveillance and early detection. In this chapter, we summarize the current state of knowledge in VHL disease.

Endolymphatic sac tumor: case report and literature review

Background

Endolymphatic sac tumor (ELST) is one of neuroectodermal tumor which arising from endolymphatic sac and duct. It is actually quite rare, with less than 200 cases reported. Although ELST presents benign appearance in histopathology, it can present aggressive destructive behavior in clinical. The cornerstone of treatment for ELST is complete surgical excision. However, it is almost impossible to completely resect the advanced stage tumor. There is still controversy about other treatments, such as radiotherapy and gamma knife surgery.

Case presentation

A 47-year-old man was admitted in The First Affiliated Hospital of Fujian Medical University with a 7-year history of progressive hearing loss and near 6-month repeated attacks of headache. Preoperative CT revealed a massive intracranial lesion and associated hydrocephalus. MR scanning demonstrated a 7.2 cm × 4.6 cm × 4.2 cm bulky mass located in left-sided posterior cranial fossa and temporo-occipital region which showed hyperintensity on T1-weighted images and mixed signal intensity on T2-weighted images. There was no neither clinical manifestation nor family history of Von Hippel–Lindau syndrome (VHL).Due to the mass that was large and invading the bone of skull base, it was difficult to extirpate surgically, so the ventriculoperitoneal shunt combined with local biopsy was performed. The postoperative pathology and immunohistochemical findings confirmed the lesion was an endolymphatic sac tumor. After operation, the patient regularly received radiotherapy.

Conclusion

The widely accepted management of ELST is complete surgical resection. However, it is difficult for surgeons to achieve radical resection with late-stage ELST. Currently, there is much dispute about the role of radiotherapy for the management of ELST in academic circles. In this case where the mass cannot be surgical removed, radiotherapy has the curative effect for ELST in terms of disease control and quality of life.

[Tumors of the inner ear and adjacent structures]

Tumors of the inner ear and adjacent structures often present with hearing loss, tinnitus and vertigo due to compression of the traversing cranial nerves. More than 90% of the tumors of the inner ear with or without expansion into the cerebellopontine angle are histologically diagnosed as vestibular schwannomas. Less common tumorous lesions include ectopic meningiomas located in the petrous bone, glomus tympanicum paragangliomas or endolymphatic sac tumors (ELST) originating in the vestibular recess. Most tumors are sporadic, but hereditary disorders have to be considered. Bilateral vestibular schwannomas are indicative of neurofibromatosis type 2 and ELST in conjunction with other abdominal tumors indicates von Hippel-Lindau disease. The neuropathological diagnostics and grading guides the subsequent therapy of these mostly benign lesions.