Tumor Types in Schwannomatosis

Schwannomatosis is defined by which tumors grow — and each tumor type produces a distinctive symptom profile independent of where in the body it appears. These are the tumors documented across SWN subtypes.

Tumor types and frequency estimates: Plotkin SR et al. Genet Med 2022; Dhamija R et al. GeneReviews Dec 2025; Evans DG et al. ERN GENTURIS. European Journal of Human Genetics. 2022. Meningioma and ependymoma rates in NF2-SWN from Dhamija R et al. and Evans DG et al. Full citations in the Knowledge Bank →

Schwannoma

All SWN subtypes

The defining tumor of schwannomatosis. Grows on the sheath of a peripheral nerve — not from the nerve itself. Can occur anywhere in the body: spinal nerves, cranial nerves, peripheral limb nerves, intramuscular nerves.

Pain at or near the tumor — burning, electric, or deep aching
A tender, palpable nodule along the nerve path
Tinel's sign equivalent — electric shock or surge of pain when the nodule is pressed
Numbness, tingling, or loss of sensation in the nerve's distribution
Weakness in muscles served by the affected nerve
Pain radiating in either direction along the nerve — does not always stay at the tumor site
Allodynia — pain from light touch near the tumor
Intermittent severe pain episodes against a background of constant baseline pain
May be present on imaging for years before causing noticeable symptoms

Vestibular Schwannoma

NF2-SWN (bilateral — defining feature)Rare in other subtypes

A schwannoma on cranial nerve VIII — the nerve responsible for hearing and balance. Also called acoustic neuroma. Bilateral vestibular schwannomas are the defining feature of NF2-SWN. Unilateral may rarely occur in other subtypes.

Hearing loss — typically high-frequency first; may progress to profound or total loss
Tinnitus: ringing, buzzing, hissing, or roaring in one or both ears
Vertigo and dizziness
Balance difficulty — especially in the dark or on uneven surfaces
Sensation of fullness or pressure in the ear
Facial numbness or weakness if the tumor grows large and compresses adjacent nerves

Meningioma

NF2-SWNSWN-SMARCB1SWN-SMARCE1

A tumor arising from the meninges — the membranes surrounding the brain and spinal cord. Present in 50–75% of NF2-SWN patients, and reported in SMARCB1 and SMARCE1 subtypes. Both cranial and spinal forms occur.

Headache — often worse in the morning or with position change
Seizures
Vision disturbances: blurring, double vision, or visual field loss
Cognitive changes: memory problems, difficulty concentrating
Weakness or numbness in one arm or leg
Personality or mood changes (frontal location)
Spinal meningioma: back or neck pain, radiculopathy, progressive limb weakness
Frequently asymptomatic for years — discovered incidentally on imaging

Ependymoma

NF2-SWN (20–30%)SWN-SMARCB1 (rare)

A tumor arising from the ependymal cells that line the spinal canal or brain ventricles. In schwannomatosis, most occur in the spinal cord.

Back or neck pain — often progressive and not relieved by standard treatments
Progressive weakness in the arms or legs
Numbness or tingling in the limbs
Bladder or bowel dysfunction
Loss of coordination or balance
Myelopathy — spinal cord compression producing clumsiness, gait difficulty, or in severe cases paralysis

Glioma

NF2-SWN (rare)

A broad category of tumors arising from glial cells — the support cells of the brain and spinal cord. Occasionally reported in NF2-SWN. Less common than schwannomas, meningiomas, or ependymomas.

Headache
Seizures
Cognitive changes or memory loss
Weakness or numbness in limbs
Vision or speech disturbance depending on location
Symptoms depend heavily on tumor location within the central nervous system

MPNST — Malignant Peripheral Nerve Sheath Tumor

Extremely rare in all SWN subtypesHighest risk: SWN-SMARCB1

A rare and aggressive malignant transformation of a nerve sheath tumor. MPNST is extremely rare in schwannomatosis, but SMARCB1-related SWN carries the highest risk among subtypes. Recognizing warning signs early is critical. This is not a routine concern for most SWN patients, but it is one every patient and specialist should know.

Rapid tumor growth — a known schwannoma enlarging over weeks rather than years
Pain that changes character or intensity suddenly at a specific tumor site
Severe, escalating pain that is no longer controlled by previous management
New or rapidly worsening neurological deficits — weakness or numbness in a nerve territory

Hybrid Schwannoma-Neurofibroma

SWN-NECRare in other subtypes

A tumor with pathological features of both schwannoma and neurofibroma — documented in schwannomatosis, particularly in gene-negative (SWN-NEC) cases. The hybrid classification is not an uncertainty about pathology; it reflects genuine biological overlap. Imaging and clinical presentation may be indistinguishable from a schwannoma. Pathology review of the excised tissue is required to identify the hybrid pattern.

Pain at or near the tumor — burning, electric, or deep aching, consistent with schwannoma-type pain
A palpable nodule or lump along the nerve path
Tenderness when the nodule is pressed
Electric or shooting pain when pressed — Tinel's sign equivalent
Numbness or tingling in the nerve's distribution
Weakness in muscles served by the affected nerve
Clinically indistinguishable from schwannoma before pathology — diagnosis requires excision and review

Multinodular Thyroid Goiter

SWN-DGCR8

Not a nerve tumor. A distinctive associated finding in SWN-DGCR8, caused by the role of DGCR8 in microRNA processing. Multinodular thyroid goiter is a documented feature of this subtype and may assist in clinical recognition.

Often asymptomatic — discovered on imaging or routine exam
Visible or palpable neck swelling
Difficulty swallowing if the goiter is large
Hoarseness if the goiter compresses the recurrent laryngeal nerve
Hypothyroid or hyperthyroid symptoms in some cases

Gene-by-Gene: Tumors, Features & Dual Diagnoses

Schwannomatosis is not one disease. It is a family of conditions, each with its own gene, its own tumor pattern, and its own set of associated findings. The same word — schwannomatosis — covers meaningfully different clinical pictures.

Note: “Dual diagnosis” rows marked with a different variant mean that those associated conditions are caused by different types of mutations in the same gene — not the same mutations that cause schwannomatosis. This matters clinically: the cancer risks in RTPS do not apply to patients with SWN-causing SMARCB1 variants.

Feature	SWN-22q (22q–related)	SWN-DGCR8	SWN-LZTR1	SWN-NEC (gene-negative)	NF2-SWN	SWN-NOS (testing pending)	SWN-SMARCB1	SWN-SMARCE1
Primary tumors	Multiple schwannomas	Multiple schwannomas	Multiple schwannomas	Multiple schwannomas	Bilateral VS + schwannomas	Multiple schwannomas	Multiple schwannomas	Multiple schwannomas
Bilateral vestibular schwannomas	✗ Exclusion	✗ Exclusion	✗ Exclusion	✗ Exclusion	✦ Defining feature	✗ Exclusion	✗ Exclusion	✗ Exclusion
Meningiomas	Possible	Not reported	None reported	Possible	Common (50–75%)	Unknown	Common	Spinal & cranial
Ependymomas	Possible	No	No	Possible	Yes (20–30%)	Unknown	Rare	No
Cataracts	No	No	No	No	Yes — childhood onset	Unknown	No	No
Thyroid tumors	No	✦ Multinodular goiter	No	No	No	Unknown	No	No
Dual Dx: Noonan syndrome	No	No	Yes — different LZTR1 variants	No	No	Unknown	No	No
Dual Dx: RTPS / rhabdoid risk	No	No	No	No	No	Unknown	Yes — different SMARCB1 variants	No
Dual Dx: Coffin-Siris	No	No	No	No	No	Unknown	Yes — different variants	Yes — different variants
Hearing loss / tinnitus	Rare	Rare	Rare	Rare	Yes — from vestibular schwannomas	Rare	Rare	Rare
Balance problems	Rare	Rare	Rare	Rare	Yes — from vestibular schwannomas	Rare	Rare	Rare
Typical onset	Unknown	Variable	Ages 20–40	Variable	Adolescence – early 20s	Unknown	Ages 20–40	Variable
Penetrance	Unknown	Unknown	40–50%	N/A	High (most carriers affected)	N/A	40–50%	Unknown
De novo rate	Unknown	Unknown	~30%	Unknown	~50%	N/A	~10%	Unknown

Sources: Plotkin SR et al. Genet Med 2022 (consensus nomenclature); Dhamija R et al. GeneReviews Dec 2025; Rivera B et al. JCI 2020 (DGCR8); Rai et al. Neuroradiology J 2025 (LZTR1 pain outcomes, SMARCB1 malignant transformation, SWN-22q). Full citations in the Knowledge Bank →

SWN-SMARCB1 and malignant transformation risk. Schwannomas in SMARCB1-related schwannomatosis have an increased propensity for malignant transformation — becoming a malignant peripheral nerve sheath tumor (MPNST) — compared to other SWN subtypes. MPNST is extremely rare in all SWN, but SMARCB1 carries the highest risk. Warning signs are rapid schwannoma growth (enlarging over weeks, not years) and severe or escalating pain at a specific tumor site that is no longer controlled by previous management. These warrant urgent specialist evaluation.

SWN-LZTR1 and pain outcomes. Research indicates that pain and pain-associated quality of life tend to be worse in LZTR1-related schwannomatosis than in other named subtypes. Spinal schwannomas are more prevalent, and segmental schwannomatosis — in which tumors cluster in one region of the body — is more common in LZTR1 patients. LZTR1 classification also carries additional diagnostic complexity: because the gene has an unusually high tolerance for loss-of-function variants in the general population, testing a single tumor may not exclude the diagnosis. Testing multiple tumor sites is recommended to avoid a false-negative.

The search for new SWN genes is not finished. Researchers are actively working to identify additional pathogenic genes in schwannomatosis. Two of the subtypes shown in this table — SWN-SMARCE1 and SWN-DGCR8 — are recent enough discoveries that they are not yet included in the UAB comprehensive schwannomatosis panel or most other standard testing panels. If your genetic testing came back negative, these subtypes may not have been evaluated.

Every patient who participates in natural history studies or answers a survey about their diagnosis timeline is helping researchers narrow the search. With that data — and with The Order’s work connecting patients to research programs — we hope that in the years to come, every SWN patient who is currently gene-negative will have their gene identified. You are not the end of the science. You are part of finding the answer.