Schwannomatosis – first reported cases in Brazil

Neuropathic pain stems various sources including schwannomatosis (SCH), a disease that affects about five thousand Brazilians. SCH is characterized by multiple and intensely painful schwannomas. Differential diagnosis of SCH includes, especially, neurofibromatosis types 1 and 2. A typical case of SCH, possibly the first recorded in Brazil, is presented and discussed in detail and compared with two other subsequent cases with regards to selected clinical and radiological aspects. A 33 year-old female patient was admitted with pain and progressive loss of strength in the left lower limb for the past five years. These complaints were associated with the appearance of very painful nodules in the same region. She also had two light brown (café-au-lait) spots (<1 cm). MRI detected soft tissue tumors in the subcutaneous and intracavitary regions. Two distinct biopsies of different regions and microscopic examination of two nodules revealed Schwann cells surrounded by abundant myxoid stroma. Immunohistochemical examination showed strong and diffuse markers of S-100 protein. Ultrastructural examination showed Schwann cells in the core areas with traces of intracytoplasmic membranes and foci of redundant basement membrane. The pain symptoms, the pattern of intraneural neoplastic growth with marked peritumoral edema, vascular hyalinization, and immunohistochemical reactivity for S-100 protein in Schwann cells in lesion cores suggested the diagnosis of schwannomatosis. Pharmacological pain treatment achieved partial remission of pain.