Page 1871 - Cote clinical veterinary advisor dogs and cats 4th

Squamous Cell Carcinoma 939

• Ketoconazole can be hepatotoxic, especially PEARLS & CONSIDERATIONS • Wash hands and forearms with chlorhexidine
in cats. Comments or povidone-iodine scrub after wearing
VetBooks.ir treated with a dosage of 5 mg/kg q 12h; • Even after treatment is completed, use of Client Education Diseases and Disorders
gloves.
• Itraconazole is hepatotoxic in 10% of dogs
immunosuppressive dosages of corticosteroids
better tolerated, fewer side effects in cats,
is contraindicated due to reports of
although hepatotoxicity can occur.
recurrence. • Sporotrichosis is a zoonotic disease, especially
in cats.
Recommended Monitoring • Duration of therapy is often ≥ 3 months. • Separation of infected animals from immu-
With itraconazole or ketoconazole administra- • Cats have been given iodide and ketocon- nosuppressed people is necessary.
tion, monitor liver enzymes q 2-4 weeks for azole, but because of high sensitivity, these
duration of therapy. are not recommended. SUGGESTED READING
Viana PG, et al: Successful treatment of canine
Prevention
PROGNOSIS & OUTCOME sporotrichosis with terbinafine: case reports and
• Limit outdoor roaming, especially in wooded literature review. Mycopathologia 183:471-478,
• Response of cutaneous or lymphocutaneous areas. 2018.
forms is fair to good. Of 266 cats treated in • Castrate male cats to diminish fighting. AUTHOR: Mauria A. O’Brien, DVM, DACVECC
one study, 68 (26%) were cured, irrespective EDITOR: Joseph Taboada, DVM, DACVIM
of extracutaneous signs or FIV status. Technician Tips
• Disseminated disease carries a guarded • Wear gloves when handling infected
prognosis. animals.

Squamous Cell Carcinoma Client Education
Sheet

BASIC INFORMATION SCC reported in young (<1-year-old) dogs; • Oral SCC in cats may be associated with
also may be seen in adult dogs. Papillary flea collar use, canned cat food or tuna
Definition SCC in adults can have a bone invasive or consumption, and (possibly) environmental
A malignant tumor arising from squamous noninvasive pattern. tobacco smoke.
epithelium • Cat: SCC is the most common oral tumor. ○ In one study, cats with SCC exposed
SCC makes up 75% of feline oral tumors to environmental smoke were more
Epidemiology and occurs in the gingival and sublingual likely to overexpress mutant TP53
SPECIES, AGE, SEX area in equal frequency. Older cats affected; than cats with SCC from smoke-free
Nasal planum (nonhaired, rostral, external part no sex predisposition environments.
of nose):
• Dog: rare site GENETICS, BREED PREDISPOSITION GEOGRAPHY AND SEASONALITY
• Cat: squamous cell carcinoma (SCC) is the Planum: • High altitude may increase the risk of solar
most common tumor in this site; older cats • Cat: lightly pigmented animals; Siamese exposure–induced SCC, as does living in
Aural: occurs in older animals: breed underrepresented countries with lower ozone coverage (e.g.,
• Dog: SCC is the second most common Aural: New Zealand).
ear canal tumor (after ceruminous gland • Cat: on pinna; lightly pigmented animals; • Tonsillar SCC is 10 times more likely to
adenocarcinoma). Siamese underrepresented occur in dogs from urban areas versus those
• Cat: SCC may affect the pinna, often in Digital: in rural areas.
cats with planum and periocular SCC; may • Dog: ≈75% large-breed dogs, ≥ 70% having Clinical Presentation
also affect the ear canal, where it is the most dark coats. Breeds at increased risk include
common tumor type, equal in frequency to giant, standard, and miniature schnauzers, HISTORY, CHIEF COMPLAINT
ceruminous gland adenocarcinoma. Gordon setter, standard and miniature • Planum and pinna: crusted or ulcerated
Digital: poodles, Scottish terrier, Labrador retriever, lesions or an actual mass ± bleeding or
• Dog: SCC is the most common digital rottweiler, and dachshund. sneezing.
tumor, 35%-55% of such tumors; age 7-11 Oral: • Aural, external ear canal: visible mass, ear
years • Dog: large dogs may be more likely to discharge, odor, pruritus, pain, facial nerve
• Cat: primary SCC of the digit is rare develop nontonsillar SCC; poodles, Labrador paralysis, head tilt, or circling. Cats are more
(<10%). Digital carcinomas usually occur as retrievers, and Samoyeds may be predisposed likely to present with neurologic signs versus
metastasis from a bronchogenic carcinoma to lingual SCC. dogs.
in older (mean, 13 years) cats. • Digital
Oral: RISK FACTORS ○ Dog: lameness, digit swelling, abnormal
• Dog: SCC is one of the three most common • Solar exposure in white-coated cats associated nail growth, fractured nail, licking/
malignant oral tumors, with nontonsillar with increased risk of nasal planum, pinnal, chewing at digit; often animals have a
SCC having a prevalence rate of approxi- and periocular SCC. history of chronic nail bed infection with
mately 7 per 100,000 dogs. Gingival area • Exposure to air pollution may be associ- no improvement with antibiotics.
is most frequently affected, followed by lips, ated with development of tonsillar SCC in ○ Cat: lameness; despite the fact that digital
tongue, palate, and pharynx. Middle-aged dogs. carcinoma in cats is usually metastatic
to older dogs affected for most oral SCCs; • Gingival SCC reported to develop after oral from a primary lung tumor, cats rarely
no sex predisposition. Gingival papillary radiation therapy in dogs. have respiratory signs.

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