Cutaneous lymphoma of the tarsus in cats: 23 cases (2000–2012)

• Autores: Holly D. Burr
• Localización: JAVMA: Journal of the American Veterinary Medical Association, ISSN-e 0003-1488, Vol. 244, Nº. 12, 2014, págs. 1429-1434
• Idioma: inglés
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• Resumen

  • Objective—To determine features of lymphoma of the tarsus in cats.

    Design—Multi-institutional retrospective study.

    Animals—23 cats with cutaneous lymphoma of the tarsus.

    Procedures—Veterinary oncologists were requested to submit cases fitting the following criteria: histologically or cytologically confirmed lymphoma with a location at or near the tarsus and described as subcutaneous or mass-like. Data regarding breed, sex, age, FeLV and FIV status, and reason for evaluation were collected. Results of staging tests, location of the tumor, immunophenotype, and histopathologic description were recorded. Type of treatments, outcome, survival time, presence or absence of progressive disease, and cause of death or reason for euthanasia were also recorded.

    Results—Most cats were older, with a median age of 12 years (range, 7 to 18 years). No association with positive retroviral status was found. Popliteal lymph node involvement at diagnosis was reported in 5 cats, and a suspicion of lymphoma at a different site on the basis of results of abdominal ultrasonography was reported in 4 cats. Treatments were variable and included corticosteroids alone (n = 2), chemotherapy (9), radiation and chemotherapy (7), or surgery with or without chemotherapy (5). Thirteen cats were reported to have lymphoma at a different site at the time of last follow-up, death, or euthanasia. Median survival time for all cats in the study was 190 days (range, 17 to 1,011 days).

    Conclusions and Clinical Relevance—Results suggested that tarsal lymphoma is an uncommon manifestation of lymphoma in cats, and in this study was most commonly nonepitheliotropic and of high grade as determined on histologic evaluation. Systemic involvement was identified; therefore, thorough staging is recommended prior to initiating treatment. Future studies are warranted to evaluate effective treatment protocols.

    Lymphoma is one of the most common neoplasms in cats; however, cutaneous lymphoma comprises only a small fraction of cases and remains poorly understood.1 Previous reports have documented cases of cutaneous lymphoma in cats as a primary disease process or secondary to systemic involvement of other primary sites. To date, the etiology remains unknown, with no consistent correlation with prior trauma or retroviral status.1 In cats and dogs, histologic evaluation differentiates cutaneous lymphoma into epitheliotropic or nonepitheliotropic forms.2 Both forms can have a similar clinical appearance, with solitary, multifocal, or diffuse lesions that are most commonly described as superficial lesions consisting of alopecia, erythema, crusting, papules, nodules, ulcers, or plaques.2–12 Cutaneous lymphoma is well described in dogs, and the epitheliotropic form is most common.13 In contrast, data regarding the prevalence of epitheliotropic versus nonepitheliotropic lymphoma in cats are limited to case reports and a few small case series. In a case series6 of 9 cats, 8 cats were classified as having nonepitheliotropic and 1 as having epitheliotropic lymphoma. Feline epitheliotropic cutaneous lymphoma has also been reported in a recent case series7 and several case reports.3,9,10,12,14 Generally, epitheliotropic cutaneous lymphoma is considered to be a disease of T lymphocytes, and nonepithelioptropic cutaneous lymphoma may be of either T- or B-cell phenotype.3,5,7,9,12,14 Prior reviews of nonepitheliotropic cutaneous lymphoma in cats indicate a slight predominance of T-cell over B-cell immunophenotype.2,5,11,15–19 Nonepitheliotropic cutaneous lymphoma in dogs is also more frequently of T-cell immunophenotype.2,13 A syndrome of cutaneous lymphocytosis, which can have a similar appearance to cutaneous lymphoma, has been reported in cats. These cats have superficial skin lesions consisting most commonly of alopecia, erythema, and scaling with or without crusting. Other less frequently reported lesions include alopecic erythematous plaques, single or multiple nodular lesions, solitary ulcers, and miliary papules. Histologically, lymphocytes are well differentiated (low grade), with no mitotic figures observed, and of mostly T-cell phenotype.20 This is thought to be a nonneoplastic disease. However, it may be difficult to separate cutaneous lymphocytosis from well-differentiated cutaneous lymphoma without further diagnostic testing such as PCR assay for antigen receptor rearrangement.21 Although cutaneous lymphoma is most commonly described as superficial dermal lesions, several reports2,6,14,15,17,19,22–24 describe it as having a subcutaneous, mass-like appearance. It was the authors' experience that this subcutaneous form had a predilection for the tarsal region. The purpose of the study reported here was to determine the features of lymphoma of the tarsus in cats.