A case of oral squamous cell carcinoma treated by mandibulectomy in a spotted seal (Phoca largha)

Most cases of squamous cell carcinoma (SCC) in pinnipeds are diagnosed postmortem; antemortem diagnosis and active therapeutic intervention are rarely reported, and prognosis is generally considered poor. We report an antemortem diagnosis of mandibular oral SCC in a spotted seal (Phoca largha) with progressive feeding difficulty due to tumor-associated pain that worsened despite analgesics. Partial rostral mandibulectomy (left second incisor to right second premolar) with lip-tissue reconstruction restored feeding by postoperative day 2. Despite tumor recurrence, the seal maintained feeding function and good quality of life for approximately 18 months. This first reported mandibulectomy in a pinniped suggests that surgery may be a valuable palliative option for oral SCC.