Von Hippel-Lindau Disease (VHL - Cerebellar Hemangioblastoma & Systemic Staging)

• Seen in young adults (peak age 20–40 years, incidence 1:36,000 live births, equal sex distribution) presenting with cerebellar ataxia, gait instability, headache, and signs of elevated intracranial pressure (vomiting, papilledema) from posterior fossa mass effect. Associated symptoms include painless vision loss (retinal hemangioblastomas), episodic severe hypertension and palpitations (pheochromocytoma), or hematuria/flank pain (clear cell renal cell carcinoma).
• Caused by autosomal dominant hereditary tumor predisposition syndrome caused by germline mutations in the VHL tumor suppressor gene located on chromosome 3p25.3:
• (1)
  Molecular Pathophysiology: Loss of normal VHL protein (pVHL) prevents ubiquitination and degradation of hypoxia-inducible factor 1-alpha (HIF-1alpha). Constitutive HIF-1alpha accumulation drives transcription of VEGF, PDGF, and erythropoietin, producing exuberantly hypervascular neoplasms and secondary polycythemia.
• (2)
  Major Diagnostic Lesions:
• 1.
  Hemangioblastomas (CNS & Retina, 60–80%): Cerebellum (most common site), spinal cord, and brainstem.
• 2.
  Clear Cell Renal Cell Carcinomas (ccRCC, 40–70%): Bilateral, multifocal renal cysts and carcinomas.
• 3.
  Pheochromocytomas & Paragangliomas (15–20%): Adrenal and extra-adrenal catecholamine-secreting tumors.
• 4.
  Pancreatic Lesions (70%): Multiple simple cysts, serous cystadenomas, and pancreatic neuroendocrine tumors (pNETs).
• 5.
  Endolymphatic Sac Tumours (ELST, 10–15%): Highly vascular, destructive temporal bone lesions causing sensorineural hearing loss.

Imaging Findings

• Magnetic Resonance Imaging (Brain & Spine MRI - Diagnostic Gold Standard Framework):
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  Hallmark Cyst with Mural Enhancing Nodule: Classical presentation in 60% of cases. Large, well-demarcated cerebellar or spinal fluid-attenuation cyst (low on T1WI, bright on T2WI) with a small, intensely enhancing peripheral mural nodule (typically <1.0–1.5 cm) abutting the pial surface.
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  Serpiginous Flow Voids: Prominent, tortuous, enlarged feeding arteries and draining pial veins demonstrating dark signal flow voids on T2WI surrounding the hypervascular mural nodule.
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  Solid Hemangioblastomas (40%): Entirely solid, intensely and homogeneously enhancing mass with surrounding vasogenic edema.
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  Whole-Spine Screening: Mandatory post-contrast whole-spine MRI to detect occult asymptomatic intramedullary spinal cord hemangioblastomas (cervical and thoracic cord).
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  DWI / ADC: Both the large fluid-filled cyst and the hypervascular mural nodule of a cerebellar hemangioblastoma show facilitated diffusion (high ADC, no diffusion restriction)—a critical pearl that differentiates hemangioblastoma from hypercellular posterior fossa tumors like medulloblastoma.
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  **SWI / T2* GRE: Demonstrates serpentine vascular flow voids / blooming vessels feeding the mural nodule and detects hemosiderin blooming in endolymphatic sac tumors** of the posterior petrous temporal bone.
• Computed Tomography & MRI Abdomen (Systemic Manifestations Framework):
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  Bilateral Renal Lesions: Multicentric renal cysts and hypervascular solid masses showing intense arterial enhancement and rapid washout (ccRCC).
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  Pancreatic Cysts & Neuroendocrine Tumours: Innumerable simple cysts replacing the pancreas; hypervascular arterial-enhancing pNETs.
• Temporal Bone High-Resolution CT:
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  Destructive, moth-eaten lytic bone erosion centered at the posterior petrous temporal bone (endolymphatic sac tumor).

Differential Diagnosis

Important Points to Remember

• Diagnostic Pitfall: Operating on a cerebellar hemangioblastoma without first screening for an undiagnosed Pheochromocytoma! Up to 20% of VHL patients harbor an unsuspected catecholamine-secreting pheochromocytoma. Inducing general anesthesia or surgical manipulation in an unblocked patient with an occult pheochromocytoma triggers catastrophic intraoperative hypertensive crisis, cerebral hemorrhage, and fatal cardiac arrhythmias. Every patient with suspected or confirmed VHL MUST undergo plasma/urinary metanephrine screening and abdominal imaging BEFORE intracranial surgery.
• Crucial Review Areas:
• 1.
  Pial surface of the cerebellum and brainstem on post-contrast T1WI: small intensely enhancing mural nodule abutting the dura/pia.
• 2.
  Entire spinal cord on contrast-enhanced sagittal T1WI to detect occult intramedullary drop lesions or synchronous spinal hemangioblastomas.
• 3.
  Kidneys on abdominal CT/MRI for multifocal solid arterializing lesions (clear cell RCC).
• 4.
  Adrenal glands on non-contrast and contrast CT/MRI for lipid-poor, hypervascular pheochromocytomas.
• Radiologist Safe Practice & Management:
• 1.
  Mandatory Pre-Operative Pheochromocytoma Screening: Immediate plasma free metanephrines and 24-hour urinary metanephrines prior to any surgical or interventional procedure.
• 2.
  Complete Neuraxis Staging: High-resolution contrast-enhanced MRI of the entire brain and whole spine (cervical, thoracic, lumbar).
• 3.
  VHL Multidisciplinary Team: Mandatory presentation to a designated National Specialist VHL Multidisciplinary Center.
• 4.
  Microsurgical Resection: Targeted microsurgical en bloc excision of the enhancing mural nodule alone (the cyst wall is non-neoplastic gliotic tissue and does not require resection).
• 5.
  Lifelong Surveillance Program: Structured annual screening: annual ophthalmologic exam (starting in infancy), annual brain and whole-spine MRI (from age 11), annual abdominal ultrasound/MRI, and annual metanephrine monitoring.