Multiple spinal nerve sheath tumors in a dog resembling schwannomatosis in humans.

A 7-y-old male neutered crossbreed dog was presented to a veterinary referral hospital with a 9-mo history of progressive non-ambulatory tetraparesis. A magnetic resonance imaging (MRI) study revealed multiple T2-weighted hyperintense intradural nodular lesions within the cervical spinal cord and nerves that were contrast-enhancing in T1-weighted post-contrast images. Neurologic signs progressed despite steroid treatment and a second MRI revealed slight enlargement of the previously seen lesions. The dog was euthanized due to severe neurologic signs. Histopathology and immunohistochemistry (laminin, S100, SOX10) confirmed multiple spindle-cell tumors from cervical spinal nerves, consistent with schwannomas. Neoplastic cells occasionally contained a large, clear vacuole (lipoblast-like change). The clinical and pathologic presentation resembles schwannomatosis, a hereditary condition in humans.