Posterior Fossa Mass

Leo SmithDecember, 2004

Patient Presentation

26-year old male from small western Oregon town~2.5 week history of headache, more painful in the morning. No significant improvement w/ pain medication.“Throbbing” behind right ear~2 week history of imbalance, nausea, and emesis.Episodes of sudden deafness.Right arm numbness.Blurred vision and diploplia.CT in home town showed right cerebellar mass.Patient referred to OHSU.

Patient Presentation (cont’d)

Family history of multiple cancers, type unknown.

Physical examination: Alert, oriented x3 Normal pupils and EOM. Normal visual fields Slight decrease in sensation in R side of body No other contributory physical exam findings

Findings: MRI, T2 Weighted

Hyperintense mass lesion within the right cerebellar hemisphere, ~ 4 x 3 x 3 cm.

Mild downward displacement of cerebellar tonsils, especially on right

Some effacement of prepontine cistern

MRI, T2 Weighted Imaging

Findings: T1 Weighted MRI

Isointense mass w/ position and size as described above

MRI, T1 Weighted, w/o Contrast

Findings: MRI w/ Contrast

Approximately 1 cm enhancing nodule within mass

MRI, T1 w/ Gadolinium Contrast

Findings on Angiography

Hypervascular mass, 8 x 12 mm, within right cerebellum

Hypervascular mass is being supplied by branches from the right anterior inferior cerebellar artery, and the right posterior inferior cerebellar artery.

Angiographic Imaging

R Vertebral Artery

Basilar Artery

Localization of Vascular Mass

Location of hypervascular massCorresponds w/ location of enhancing nodule

Differential Diagnosis

Hemangioblastoma most common posterior fossa primary neoplasm in adults

Juvenile pilocytic astrocytoma Most common posterior fossa primary neoplasm in children

Metastatic tumor Most common intra-axial, infratentorial tumor in adults Typically have a significant amount of edema surrounding

tumor

Ganglioglioma Typically show calcification

Diagnosis

Hemangioblastoma, based on: Imaging characteristics and location of mass Age of patient

Cannot rule out juvenile pilocytic astrocytoma (JPA) at this time.

Hemangioblastoma and JPA can be distinguished on pathology exam

Metastasis unlikely because: Young age of patient Absence of signs of primary neoplasm elsewhere in body Limited extent of surrounding edema seen in this patient

Treatment

Evidence of neurological deficit or hemorrhage are indications for surgical resection

Pre-surgery embolization of feeding arteries, where possible

Should consider adjuvant radiotherapy in cases with positive surgical margins or incomplete resection

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Typical Surgical Finding

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Outcome for This Patient

Nodule and surrounding cyst successfully resected

Pathology confirmed diagnosis of hemangioblastoma

Relatively uneventful post-op stay

Discharge to home post-op day 5.

Hemangioblastomas

Diagnostic Characteristics of Hemangioblastomas (1)

A. MRI1. Enhancing nodule associated with cyst, located in the cerebellum.

2. Smaller HBs (<10 cm) can appear isointense on T1 and hyperintense on T2 imaging.

3. Can also present as uniformly enhancing lesion on surface of or within spinal cord.

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Diagnostic Characteristics of Hemangioblastomas (2)

B. Angiography: Highly vascularlized mass

C. Blood count: In 15-20% of pts. with hemangioblastoma there is a perineoplastic erythrocytosis (w/ elevated RBC and hematocrit). This is due to extra-renal erythropoietin production.

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Characteristics of Hemangioblastoma

Hemangioblastomas (HBs) account for 7-10% of all posterior fossa primary neoplasms

Most are found in young adults

Within the neuraxis, hemangioblastomas occur most often in the cerebellum, but also occur in Spinal cord Medulla Pituitary stalk

Important Considerations w/ Hemangioblastoma (1)

~25% of pts. w/ CNS hemangioblastomas have von Hippel-Lindau (vHL) disease

Sporadic HBs typically appear in 5th or 6th decade; vHL-associated HBs typically appear in 3rd or 4th decade. Therefore, if pt. under 50 is found to have HB, pt. should be screened for vHL

Important Considerations w/ Hemangioblastoma (2)

vHL is an autosomal dominant inheritable disease

vHL predisposes to multiple tumors, including: Neuraxial HBs Retinal HBs Renal cell cysts and renal cell carcinoma Pheochromocytomas Pancreatic cysts and pancreatic serous cystadenomas Pancreatic and neuroendocrine tumors

vHL can be diagnosed by genetic testing, or by meeting certain criteria

Is it von Hipple-Lindau?

Pt. likely has vHL if:A. Multiple CNS hemangioblastomas (presumptive

vHL),

OR

B. Neuraxial hemangioblastomas with other neoplasms outside CNS

Diagnostic Criteria for vHL1

A. More than one HB of the CNS or retina, or isolated HB in association with any of following:

pheochromocytoma renal carcinoma pancreatic involvement

B. A first-degree relative w/ vHL and any one manifestation

Follow-Up for Pts. w/ Established vHL1

1) Annual physical examination and urine test

2) Annual ophthalmology exam

3) MRI of brain q 3 years to 50 y.o., q 5 years thereafter

4) Annual abdominal MRI

5) Annual 24-hour urine test for vanillylmandelic acid (VMA)--screen for pheochromocytoma

Screening Recommendations for Relatives at Risk1

1) Annual physical and urine test after 5 y.o.

2) Annual ophthalmology exam from 5-60 y.o.

3) Brain MRI q 3 yrs. from 15-40 y.o., q 5 yrs. thereafter

4) Annual abdominal MRI from 20-60 y.o.

5) Annual 24-hour urine test for VMA

References

1. Maddock IR, et al. A genetic register for von Hippel-Lindau disease. J Med Genet 33(2):120-127, 1996.

2. Slater A, et al. The Natural History of Cerebellar Hemangioblastomas in von Hippel-Lindau Disease. Am J Neuroradiol, 24:1570-1574, Sep 2003.

3. Grainger RG. Grainger & Allison’s Diagnostic Radiology: A Textbook of Medical Imaging, 4th ed. p 2336 Churchill Livingstone, Inc. Edinburgh, UK, 2001.

4. Choyke PL, et al. Von Hippel Lindau Disease: Genetic, Clinical and Imaging Features. Radiology (March) 146:629-642, 1995.

5. Wong ET, et al. Hemangioblastoma. UpToDate. www.uptodate.com.

The End

Embolization of Hemangioblastoma

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Enhancing Nodule and Cyst

Gd enhancing noduleAssociated with cyst.

T1 weighted MRI with Gd contrast

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Hemangioblastoma, MRIT1 vs. T2

T1: Isointense T2: Hyperintense

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Hemangioblastoma Spinal Lesion

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Angiogram of vascularized mass

Mass with high vascularity

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