Table 2. Mutations associated with intradural extramedullary (IDEM) tumors.

Tumor	Gene	Locus	Grade	Molecular finding
Meningioma	–	22	I–III	Most consistently reported finding of spinal meningioma
	MMP9	20q11.2	I–III	Overexpressed in spinal meningiomas via IHC
	SMARCE1	17q21.2	I–III	Familial spinal meningiomas in patients without NF2; all clear-cell histology
Schwannoma	NF2	22q12	–	Germline inactivating mutations
	SMARCB1	22q11	–	Germline alteration in ~50% of familial and ~10% of sporadic schwannomatosis cases
	LZTR1	22q11	–	Germline LoF in majority of schwannomatosis cases lacking mutations in SMARCB1, but with loss of chromosome 22q in tumors
	ARID1A	1p36.11	–	Recurrent somatic mutations in sporadic schwannomas, identified by WES
	ARID1B	6q25.3	–
	DDR1	6p21.33	–
	SH3PXD2A-HTRA1	–	–	Recurrent fusion in 10% of sporadic schwannoma

IHC, immunohistochemistry; LoF, loss-of-function; WES, whole-exome sequencing.