[Intracranial and intramedullary peripheral nerve sheath tumours. Case reports from 20 autopsies]

Tumors arising from the sheath of peripheral nerves, both intracranial and intraspinal, are uncommon and are sometimes of difficult clinical diagnosis, especially when they occur in unusual sites. Schwannomas, neurofibromas and perineuromas are depicted in this descending order of frequency. Most are sporadic and some can be part of hereditary syndromes. Histological malignancy of this neoplasm is rare.

The clinical and pathological findings of 20 autopsy cases of intracranial and intraspinal peripheral nerve tumors are analyzed. The average age at presentation was 35 years and the male/female ratio was 1:1.

19 were schwannomas, 13 of the 8th cranial nerve (two associated with neurofibromatosis type 2), two originated in the trigeminal and one in the 12th nerves. Three were intraspinal, one of this underwent malignant changes and was part of neurofibromatosis type 1 (NF-1), another was an intraspinal lumbar mass with schwannomatosis and the third was a case of multiple intraspinal neurofibromas as a part of NF-1. 14 cases were surgically treated and the causes of death were ischemic lesions due to the large size of the tumors. The correct clinical diagnosis was made in 14 patients. In 11 instances there was corroboration by biopsy. Three were misdiagnosed and three were autopsy findings.

In this series more cases were sporadic. No sex predominance was encountered. The importance of early detection on intracranial and intraspinal peripheral tumors is paramount, since the large size of these histologically benign neoplasms makes them biologically malignant.