Small Animal Dermatology, 3rd edition

616 DISEASES/DISORDERS

Paraneoplastic pemphigus: multiple epidermal plakin family proteins and

desmogleins targeted; T cell-mediated keratinocyte apoptosis may contribute to

lesion development

Multiple collagenous nevi: potential increase in local production of TGF-alpha

and beta-1 cytokine resulting in proliferation of fibroblasts and excess collagen

Renal cystadenocarcinoma and nodular dermatofibrosis: result of autosomal

dominant genetic defect; a missense mutation of theFLCN(folliculin)/BHDgene

on chromosome 5 may contribute to renal or uterine muscle tumors in German

shepherd dogs

Superficial necrolytic dermatitis (hepatocutaneous syndrome, necrolytic migra-

tory erythema, metabolic epidermal necrosis): most often associated with hep-

atopathy; rare association with glucagon-secreting pancreatic or extrapancreatic

neoplasia; glucagonemia-induced glycogenesis results in hypoaminoacidemia,

causing keratinocyte degeneration

Cutaneous changes due to hyperadrenocorticism (see relevant chapter).

 Feline preneoplastic dermatoses:
Actinic keratoses: similar to canine (see relevant chapter)
Cutaneous lymphocytosis: expansion of T cells in response to persistent anti-

genic stimulation such as drugs or vaccines; clonal rearrangement may result in

overt lymphoma.

 Feline paraneoplastic dermatoses:
Pancreatic/hepatic paraneoplastic alopecia:
Majority of cases are associated with an underlying pancreatic adenocarci-
noma
Other internal carcinomas, such as bile duct and hepatocellular carcinomas,
may be involved
Most affected cats with pancreatic adenocarcinomas have metastases to
liver, lungs, pleura, and/or peritoneum; reports of bile duct and hepato-
cellular carcinomas
Clinical symptoms may involve cytokines producing atrophy of the hair
follicles
Feline thymoma-associated exfoliative dermatitis:

Elevated numbers of CD3+ lymphocytes within the dermis

Proposed induction of autoreactive T lymphocyte attack on follicles.

SIGNALMENT/HISTORY

 Canine preneoplastic dermatoses:
Actinic keratoses:
No sex predilection
Age: usually older animals; reported as young as 2 years
Breed predilections: dalmatian, whippet, Italian greyhound, greyhound,
American Staffordshire and bull terrier, beagle, German short-haired
pointer, boxer, basset hound