Nerve sheath tumours in the dog and cat

Abstract

Schwannomas were diagnosed in twelve dogs and five cats at Massey University Small Animal Clinic and Hospital over a 15-year period (1977-92). A further two feline cases were reported at the Batchelar Animal Health Laboratory. In six dogs, the tumour involved nerves of the brachial plexus. Clinical signs observed in these dogs were forelimb lameness, muscle wasting and pain on movement of the affected limb or neck. Hindlimb paresis was observed in two dogs. Surgical excision of the brachial plexus tumour was attempted in one dog, leading to an 8-month remission of signs. In one dog, the tumour involved the sacral nerves, and in two dogs the cranial nerves were affected. Three dogs had skin nodules. Seven of the twelve affected dogs were destroyed. In five cats, the tumours developed on the carpus, tarsus or interdigital area of a forelimb or hindlimb as a slowly developing nodular lesion. In the other two cats, the site of the tumour was the flank and the lateral thigh respectively. Surgical excision of the tumour was successful in three cats.

Feline Peripheral Nerve Sheath Tumors

“…Most cats were domestic short haired (30 of 48, or 63%), but 38% of the histologically malignant tumors were in purebred cats versus 10% of the histologically benign tumors. Of the cases in which the breed affected was reported in the previous literature, 1,5,6,11,12,17,19,20,22 24 of 28 (86%) were domestic short haired, 3 of 28 (11%) were domestic long haired, and 1 of 28 (4%) was a Manx. Most tumors in this study were on the head (42%) and the limbs (26%).…”

“…Of the other cases in which the sex was reported in the peer-reviewed literature 1,[5][6][7]11,12,17,[19][20][21] and 2 textbooks, 2,4 28 of 104 (27%) were spayed females, 31 of 104 (30%) were intact females, 25 of 104 (24%) were neutered males, and 20 of 104 (19%) were intact males. In this study, many different cat breeds were represented.…”

“…Therefore, the mitotic index alone is not predictive of potential for recurrence. Of the cases in the literature for which follow-up information was given, 1,2,[4][5][6]11,12,19,20 16 of 41 (39%) were reported to recur, in some cases up to 6 times. 5 Sixteen of the PNSTs from 13 cats in this study were considered histologically malignant.…”

“…Each describes either a single case or a series of 7 or fewer cases. Seven of these reports include information regarding biologic behavior, 1,5,6,11,12,19,22 and only 5 include immunohistochemistry. 5,11,17,19,20 Two veterinary textbooks 2,4 provide some summarized information regarding PNSTs in the collections of the books' authors, and a third textbook 18 briefly describes a case of perispinal feline PNST.…”

“…Primarily because of uncertain histogenesis in veterinary medicine, PNSTs are simply divided into benign and malignant variants in the most recent edition of the WHO International Histological Classification of Tumors of Domestic Animals. 8 The published information on PNSTs in cats is limited (Tables 1, 2), with only 10 peer-reviewed articles 1,[5][6][7]11,12,17,19,20,22 spanning 31 years. Each describes either a single case or a series of 7 or fewer cases.…”