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.