Cutaneous paraneoplastic disease: Sometimes prognosis remains poor - DVM
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Cutaneous paraneoplastic disease: Sometimes prognosis remains poor


DVM360 MAGAZINE


Multicentric squamous cell carcinoma in-situ (Bowen's disease) presents as single, but more commonly multicentric, eroded crusted papules and plaques on the head, neck, shoulders or forelegs of older cats (older than 10 years). These lesions are not associated with solar exposure of non-pigmented skin. There is a long clinical course with minimal progression. Some cats may have concurrent Demodex cati infestation of the lesions. As this disease is likely due to localized loss of immune competence complete evaluation of health status, including FeLV and FIV testing is indicated. Histopathological examination shows epidermal dysplasia without disruption of the basement membrane. Surgical (laser) excision is the treatment of choice. Radiation, cryosurgery and synthetic retinoid therapy have been suggested as appropriate adjunctive treatments. Recent work with topical 5-percent imiquimod cream (Aldara®, 3M Pharmaceuticals), a local immunological response modifier is promising; cats may develop reversible leukopenia following ingesting (via grooming) imiquimod cream that was placed on their lesions.

Cutaneous lymphosarcoma occurs in older dogs with no sex predilection but with a predilection for Boxers, Cocker Spaniels, Beagles, German Shepherds, Golden Retrievers and Scottish Terriers. It is uncommon in cats. Cutaneous lymphosarcoma is usually generalized or multifocal and can present as nodules, plaques, ulcers, erythroderma and/or exfoliative dermatitis. It can occur with or without other systemic involvement. Pruritus is very common. Histopathologically, cutaneous lymphosarcoma in the dog can be divided into epitheliotropic and non-epitheliotropic types. Epitheliotropic (following or hugging the epidermis histologically) forms of cutaneous lymphosarcoma have been shown in the dog to usually be of T-lymphocyte origin while non-epitheliotropic forms are usually of B-lymphocyte origin. Non-epitheliotropic lymphosarcomas are characterized by diffuse dermal and subcutaneous infiltration by malignant lymphocytes. The epitheliotropic form is often termed mycosis fungoides. It often begins as a generalized pruritic exfoliative dermatitis or erythroderma, and progresses over a variable length of time (weeks to months) to nodules and plaques, ultimate systemic involvement and death. Canine mycosis fungoides also may have a primarily mucocutaneous distribution. Clinical management of cutaneous lymphosarcoma, with or without concurrent systemic involvement, is difficult. Response to standard chemotherapeutic protocols used in lymphosarcoma of other organ systems are disappointing; 40 percent to 50 percent success rate may be seen using isotretinoin (Accutane®: Roche US Pharmaceuticals; AmnesteemTM: Bertek Pharmaceuticals), 3-4 mg/kg daily. Prednisone (1 mg/kg daily) may alleviate some of the pruritus. Lomustine (CCNU), an alkylating agent, has been effective in the treatment of dogs with cutaneous lymphoma at a dose of 50 mg/m2 every 21-30 days. Remission lasts from two to 15 months. Neutropenia may be seen and is most likely to occur one to two weeks after treatment, although this has usually been noted with higher doses. While generally a safe drug, irreversible hepatic toxicity (again, generally at higher doses) has been reported.

Dr. Hoskins is owner of DocuTech Services. He is a diplomate of the American College of Veterinary Internal Medicine with specialities in small animal pediatrics. He can be reached at (225) 955-3252, fax: (214) 242-2200, or e-mail:


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Source: DVM360 MAGAZINE,
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