Clinical History
26 year old female with tingling of the medial aspect of the great toe.
Diagnosis: Schwannomatosis
Schwannomatosis is a genetic condition presenting as multiple benign tumors (schwannomas) of the peripheral nerves, similar to neurofibromatosis types I and II.
Mutations in either the SMARCB1 or the LZTR1 gene, which encode for tumor suppressor proteins, are implicated in schwannomatosis.
Patients with schwannomatosis present with nerve related symptoms depending on the nerves affected.
Unlike neurofibromatosis type I, development of malignant tumors is not a feature, and unlike neurofibromatosis type II, vestibular nerve involvement is not a feature in schwannomatosis.
If there is a concern for a nerve sheath tumor in any patient presenting with nerve symptoms, MRI or ultrasound would be the appropriate initial work-up.
Masses along the course of a nerve or multiple nerves would be consistent with either neurofibromatosis or schwannomatosis. Additional tests, including MRI of the brain and genetic tests, would be required to differentiate among these three conditions.