Chemotherapeutic Management in a Labrador Retriever with Cutaneous Nonepitheliotropic B-cell Lymphoma

A 9-month-old, castrated, male Labrador Retriever was referred for generalized progressing cutaneous reddish mass lesions with bleeding, scale, crust, and pruritus. On the basis of histopathological findings and the results of immunochemical staining, cutaneous nonepitheliotropic B-cell lymphoma was identified. A cyclophosphamide-doxorubicin-vincristine-prednisolone (CHOP)-based chemotherapy regimen was initiated, and the patient initially showed partial response to vincristine and $\text\tiny{L}$-asparaginase, but the cutaneous lesions progressed gradually. After the first cycle of the CHOP-based protocol, lomustine was administered instead. The cutaneous lesions showed partial response to lomustine, but the treatment did not stop the progression of cutaneous lymphoma. The patient was euthanized due to neurologic signs, including reduced consciousness and seizures, 53 days after initial presentation. The postmortem histopathological examination showed systemic metastasis involving the lymph nodes, skin, kidney, ureter, liver, brain, temporal muscle, diaphragmatic muscle, conjunctiva, and oral cavity.