medwireNews: A high proportion of children and young adults with apparently solitary schwannoma or meningioma have mutations in known constitutional tumor predisposition genes, study data show.
Miriam Smith (University of Manchester, UK) and colleagues say their findings “highlight the need for clinical assessment and genetic testing in young people with an isolated meningioma or schwannoma.”
The researchers analyzed screening data from the Manchester Centre for Genomic Medicine for 63 patients presenting with a solitary meningioma and 153 presenting with a solitary schwannoma, before the age of 25 years in both cases.
As reported in JAMA Neurology, 54.0% of patients in the solitary meningioma cohort had a constitutional mutation in a known meningioma predisposition gene: 39.7% had a constitutional NF2 mutation and 14.3% had a constitutional SMARCE1 mutation. None of the patients had constitutional mutations in SMARCB1 or SUFU, the other two genes tested.
Among the patients with a solitary schwannoma, 28.8% had a mutation in a known predisposition gene: 18.3% in NF2, 6.5% in LZTR1, and 3.9% in SMARCB1.
The mutation rates were significantly higher for spinal meningiomas and schwannomas than for cranial tumors at 81.8% and 54.5% versus 39.0% and 18.3%, respectively.
The researchers note that the study participants included individuals with neurofibromatosis type 2 (NF2) disease that was identified retrospectively, after they presented with a single meningioma or schwannoma, when other NF2 symptoms developed.
Because this could lead to bias and overestimation of NF2 frequency, Smith and team also conducted a separate analysis including only patients with DNA prospectively isolated at the time of presentation, who were referred on the basis of their young age alone.
In this group, 16 (38.1%) of 42 patients with an isolated meningioma (median age 11 years, 52.4% women) had a constitutional mutation: 16.7% in NF2 and 21.4% in SMARCE1.
And 27 (20.0%) of 135 patients with an isolated schwannoma had genetic predisposition to this tumor type: 8.1% had a mutation in NF2, 7.4% in LZTR1, and 4.4% in SMARCB1.
Based on their findings, the researchers recommend “that young patients presenting with an isolated meningioma or schwannoma, including those with intracutaneous schwannomas, obtain a full assessment to exclude additional tumors.”
They add: “This assessment should include full craniospinal magnetic resonance imaging with an NF2 protocol that includes 1-mm imaging-section thickness through the internal auditory meatus and after the use of contrast imaging.
“A full dermatologic examination for NF2 plaques and an ophthalmologic examination for retinal hamartoma and lens opacity are also advised.”
By Laura Cowen
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