Peripheral nerve sheath tumors

Peripheral Nerve Sheath Tumours (PNST) are challenging problems for clinicians for three main problems:

They are slow growing neoplasms and their clinical signs appear insidiously. They constitute diagnostic pitfalls and are often considered only after exclusion of other causes of lameness in dogs and cats. This late diagnosis most often requires the use of a very aggressive surgical treatment, excluding any attempt at conservative treatment. Even if most of these tumours are benign, controversy still exists concerning their exact origin.

Epidemiology

PNST represent 0.7% of tumours (all origins) observed in dogs and 0.02% in cats (26.6 % of nervous system tumours). They are rarely metastatic, although pulmonary metastasis has been reported. Most of tumours are described in 2 to 17 years of age (male) dogs (2/1 or 1/1 sex ratio are described). Greyhound seems to be predisposed. Most of tumours occur in the brachial plexus nerves (C6T2), but all other nerves are potentially affected. Secondary extension may affect the spinal cord. Cranial nerve locations are described in the trijeminal, vestibulo-cochlear or occulomotor nerves.

Secondary tumours may invade peripheral nerve from its vicinity, they are muscle tumours (leiomyomas and leiomyosarcomas), rhabdomyomas and rhabdomyosarcoma) or bone tumors such as osteosarcomas and chondrosarcomas, and others. [...]