Cutaneous T-cell lymphoma: is it possible to monitor progression beyond skin lesions? Case report

Canine cutaneous T-cell lymphoma (CTCL) is an aggressive neoplasm that is challenging to manage and is often associated with a guarded to poor prognosis. This case report aimed to describe the clinical and therapeutic aspects of a 14-year-old spayed female dog diagnosed with CTCL, while also assessing the possibility of monitoring disease progression beyond skin lesions using laboratory parameters. Management included surgical excision followed by sequential chemotherapy protocols, initially with lomustine and later with isotretinoin combined with prednisolone. The disease progression was monitored through serial hematological and biochemical analyses performed at six different time points. The results showed tumor recurrence, therapeutic failure, and clinical progression of the disease, leading to a total survival of 82 days. Among the evaluated laboratory parameters, only alanine aminotransferase (ALT) showed a progressive and statistically significant increase (p = 0.0188). The other hematological parameters remained stable over time. It was concluded that the increase in ALT was the most reliable laboratory marker for clinical deterioration, suggesting hepatic involvement due to either neoplastic infiltration or drug-induced hepatotoxicity. This case reinforces the relevance of serial biochemical monitoring as a complementary tool for clinical follow-up and therapeutic decision-making in dogs with CTCL, particularly in palliative care contexts.