Definition (OLD) for new see SPS
- A usually sporadic and sometimes autosomal dominant disorder
- Characterized by multiple schwannomas (spinal, cutaneous, and cranial) and multiple meningiomas (cranial and spinal),
- Associated with inactivation of the NF2 gene in tumours but not in the germline, and caused by mutations in SMARCB1 on 22q or LZTR1 on 22q.
Clinical and molecular diagnostic criteria
- Hard in paeds because the Bilateral VS might develop later in life
- Definite diagnosis
- Molecular criteria:
- ≥2 schwannomas/meningiomas (pathology proven) + at least two tumours with LOH for chromosome 22 + two different NF2 mutations OR
- One schwannoma or meningioma (pathology proven) + SMARCB1 germline mutation
- Clinical criteria:
- ≥2 schwannomas (non-dermal, one pathology proven) + no bilateral vestibular schwannomas (by thin-slice MRI) OR
- One schwannoma or meningioma (pathology proven) + first-degree relative affected by schwannomatosis
- Possible diagnosis
- Clinical criteria:
- Two or more schwannomas (no pathology) OR
- Severe chronic pain associated with a schwannoma
General
- To dx schwannomatosis, need to exclude NF1 or NF2
- Aka
- Neurilemmomatosis
- Multiple schwannomas
- Multiple Neurilemmomas
Numbers
- 1/40-80K (similar to NF2)
- Familial accounts for only 10-15%
Clinical features
- CNS neoplasm
- Schwannomas
- In spinal roots, cranial nerves, skin, and (occasionally) unilaterally in the vestibular nerve.
- Severe pain; where as NF2 no pain but neuro deficits and polyneuropathy is common
- Meningiomas
- SMARCB1 germline mutations also predispose individuals to the development of multiple meningiomas, with preferential location of cranial meningiomas at the falx cerebri
- 5% schwannomatosis pt develop meningiomas
- Extra CNS manifestation
- Rare unlike in NF1/NF2
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