Table 1.
Clinical overlap and differences between NF2 and schwannomatosis
| Clinical features | Frequency of clinical feature | |||
|---|---|---|---|---|
| NF2 (references) | Schwannomatosis (references) | |||
| Bilateral vestibular schwannoma | 90–95% | Evans et al. (1992), Parry et al. (1994), Mautner et al. (1996) | Absent | MacCollin et al. (1996), Merker et al. (2012) |
| Unilateral vestibular schwannoma | 18%a | Evans et al. (1999) | Rareb | |
| Intracranial nonvestibular schwannoma | 24–51% | Parry et al. (1994), Mautner et al. (1996), Fisher et al. (2007) | 9–10% | Merker et al. (2012), Li et al. (2016) |
| Intracranial meningioma | 45–58% | Evans et al. (1992), Parry et al. (1994), Mautner et al. (1996), Patronas et al. (2001) | 5% | Merker et al. (2012) |
| Spinal tumour | 63–90% | Parry et al. (1994), Mautner et al. (1996), Patronas et al. (2001), Dow et al. (2005), Mautner et al. (1995), Rennie et al. (2008) | 74% | Merker et al. (2012) |
| Ependymoma | 18–58% | Dow et al. (2005), Mautner et al. (1995), Rennie et al. (2008), Plotkin et al. (2011) | Absent | Gonzalvo et al. (2011), Merker et al. (2012) |
| Peripheral nerve schwannoma | 68% | Evans et al. (1992) | 89% | Merker et al. (2012) |
| Subcutaneous tumourc | 43–48% | Evans et al. (1992), Mautner et al. (1997) | 23% | Merker et al. (2012) |
| Skin plaquesd | 41–48% | Evans et al. (1992), Mautner et al. (1997) | Absent | Merker et al. (2012) |
| Intradermal tumour | 27% | Evans et al. (1992) | Absent | MacCollin et al. (1996) |
| Retinal hamartoma | 6–22% | Parry et al. (1994), Mautner et al. (1996), Ragge et al. (1997) | Absent | MacCollin et al. (1996) |
| Epiretinal membrane | 12–40% | Bosch et al. (2006), Ragge et al. (1995) | Absent | MacCollin et al. (1996) |
| Subcapsular cataract | 60–81% | Evans et al. (1992), Parry et al. (1994), Bosch et al. (2006) | Absent | MacCollin et al. (1996) |
aPatients with unilateral vestibular schwannoma and other NF2-related tumours who fulfil the Manchester criteria (Evans et al. 2005) have a high risk of developing a contralateral tumour, especially if the patients are younger than 18 years of age at the time of diagnosis (Evans et al. 2008). Furthermore, 60% of patients with unilateral vestibular schwannomas exhibit somatic mosaicism for an NF2 mutation (Evans et al. 2007)
bTo date, germline LZTR1 mutations have been identified in five patients with unilateral vestibular schwannoma and at least two nonvestibular, nonintradermal schwannomas (Smith et al. 2012a, 2015, 2016). A germline SMARCB1 mutation has been identified in a single family with unilateral vestibular schwannoma (Wu et al. 2015). Mehta et al. (2016) have also reported a schwannomatosis patient exhibiting a unilateral vestibular schwannoma but without germline SMARCB1 or LZTR1 mutations
cSubcutaneous tumours are histologically schwannomas of peripheral nerves visible as nodular tumours
dSkin plaques are discrete, well-circumscribed, and slightly raised cutaneous lesions usually less than 2 cm in diameter. They are regarded as schwannomas and exhibit a rough surface often with hyperpigmentation and excessive hair