Those affected usually see a doctor to address chronic pain during adulthood (median age at the onset of symptoms is 30 years, with a median age at diagnosis of 40 years). During the evaluation of the symptoms, the clinical or imaging examination reveals schwannomas, which can compress or displace nerves and cause pain. However, the location of the pain and the position of the schwannomas are not always well correlated. Nor are the pain intensity and frequency always adequately explained by the presence of the tumor either. Although pain is the most common and usually only complaint, schwannomas – depending on their position – can also cause other neurological symptoms such as numbness, tingling or prickling (paresthesia), bladder and rectal function disorders, visual disorders, and headaches.
One special form of schwannomatosis can be clinically apparent due to cranial pressure symptoms with headaches and vomiting on an empty stomach (vomiting at night or early in the morning after waking up), whereby meningiomas are diagnosed as being the cause in the course of the evaluation. Neurological failures occur depending on the location of the tumor. This form is also called meningiomatosis.
If there are more than 2 schwannomas which are not located in the skin, even if they have not been confirmed by tissue analysis, the diagnosis of schwannomatosis is nevertheless suspected – especially if there is chronic pain.
Segmental schwannomatosis is defined as the occurrence of schwannomas in only one extremity or limited to 2 spinal segments (30% of patients have segmental schwannomatosis).