Small Animal Dermatology, 3rd edition

CHAPTER 46 TUMORS, COMMON SKIN AND HAIR FOLLICLE 679

 Digit involvement: amputation.

 Pinna involvement: may require partial or total resection.

 Invasive tumors of the nares: removal of the nasal planum recommended.

 Radiotherapy: recommended for inoperable tumors or as adjunct to surgery.

 Adjunctive chemotherapy: recommended with incomplete surgical excision, nonre-

sectable mass, and metastasis.

 Cisplatin (dogs, do not use in cats), carboplatin, and mitoxantrone: reported to induce

partial and complete remission; generally of short duration; small number of patients;

do not use with concurrent renal disease.

 Intralesional sustained-release chemotherapeutic gel implants (dogs): contain either

5-fluorouracil or cisplatin.

 Firocoxib 5 mg/kg PO q24h: overexpression of cyclooxygenase (COX-2) documented

in actinic keratoses in humans and dogs; improvement noted with use of COX-2

selective inhibitor; may be helpful in conjunction with chemotherapeutic agents.

 Vitamin E: stabilize cell membranes: 400–600 IU PO BID.

 Cimetidine: reported to have some benefit as a biologic response modifier in malig-

nant melanoma by reversing suppressor T cell-mediated immune suppression.

COMMENTS

Client Education/Prognosis

 Squamous cell carcinoma:
Discuss risk factors associated with the development of the tumor (ultraviolet

light exposure)

Monitor patient with physical examination and radiography 1, 3, 6, 9, 12, 18,

and 24 months after treatment or if the owner thinks the tumor is recurring

Thoracic and abdominal radiography: at each recheck examination, if the lesion

is on the caudal portion of the patient

Limit sun exposure, especially between the hours of 10.00 a.m. and 2.00 p.m.

Sunscreens: may help in some areas (e.g., pinnae)

Prognosis: good with superficial lesions that receive appropriate treatment;

guarded with invasive lesions and those involving the claw fold or digit.

 Melanocytic tumors:
Breed may be prognostic: 85% of miniature poodle melanomas are behaviorally

malignant,>75% of melanomas in dobermans and schnauzers are benign

Location may be prognostic: most oral, scrotal, and mucocutaneous (except the

eyelid) melanomas are malignant, 50% of claw fold melanomas are malignant

35–50% of melanomas in cats are reported to be malignant.

 Basal cell tumors:
Most are benign and easily cured with excision
Malignant tumors are typically slow growing and of low-grade malignancy; com-

plete staging, including regional lymph node aspiration, chest radiography, and

abdominal ultrasonography are advised.