Small Animal Dermatology, 3rd edition

chapter 41 Pre- and Paraneoplastic Syndromes.........................

DEFINITION/OVERVIEW

 Preneoplastic dermatoses: lesions with a malignant predisposition; atendencyto

become tumors (not consistent).

 Paraneoplastic dermatoses: lesions resulting from the metabolic effects of internal

malignancy; often a marker for specific cancer.

 Categorizing preneoplastic versus paraneoplastic dermatoses: difficult in some syn-

dromes – progression from a reactive pattern to overt neoplasia may be inconsistent.

ETIOLOGY/PATHOPHYSIOLOGY

 Canine preneoplastic dermatoses:
Actinic keratoses: ultraviolet light (UVL) causes DNA damage directly and indi-

rectly by free radicals; specific UVL-induced mutations have been documented in

the tumor suppressor gene p53, leading to expansion of mutated keratinocytes;

may represent a premalignant condition; close association of and genetic simi-

larities between AK and squamous cell carcinoma (SCC); actinic carcinomain

situdenotes SCC that has not penetrated to the dermis (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

Cutaneous mastocytosis: a specific mutation in mast cells leading to systemic

mastocytosis has not been identified; associated with mutations of thec-kitonco-

gene in human beings

Nodular fasciitis: benign reactive lesion, possibly due to trauma; occasionally

used to describe proliferative inflammatory processes, including reactive histio-

cytosis.

 Canine paraneoplastic dermatoses:
Cutaneous (primary nodular) amyloidosis: increased production of amyloido-

genic immunoglobulin light chains by proliferating plasma cells; associated with

multiple myeloma and extramedullary plasmacytoma; associated with chronic

inflammatory conditions

Cutaneous mucinosis (secondary): excessive accumulation of mucin in the der-

mis rarely associated with mast cell tumors

Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dermatology, Third Edition.
Karen Helton Rhodes and Alexander H. Werner.
©2018 John Wiley & Sons, Inc. Published 2018 by John Wiley & Sons, Inc.

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