B-Cell Lymphoma of the Middle Ear Treated with Multidrug Chemotherapy in a Cat

SIMPLE SUMMARY: Feline lymphoma can arise in a variety of sites, with the pathogenesis differing according to the site of origin. Although cases of primary lymphoma of the middle ear have been reported, information on treatment efficacy and prognosis remains lacking. In this study, an 11-year-old, spayed female mixed-breed cat was diagnosed with primary lymphoma of the middle ear. Prednisolone had been used as an anti-inflammatory drug with suspicion of otitis media for 4 months before diagnosis of lymphoma. We suspected that the cat could have maintained in good general condition because prednisolone was one of the anticancer agents for lymphoma. Multidrug anticancer chemotherapy was started and proved to be effective. The patient’s condition had been stable for another 4 months. Unfortunately, invasion from the middle ear to the nasopharynx caused difficulty with nasal breathing, liver involvement was suspected, and she died of seizures on day 228. Primary feline lymphoma of the middle ear might respond well to chemotherapeutic treatment. The prognosis for this type of lymphoma may not be as terrible as previous reports. ABSTRACT: Primary lymphoma of the middle ear is rare in cats, and little information has been accumulated on the treatment and course. An 11-year-old spayed female mixed-breed cat was brought to our hospital with facial nerve paralysis, which had been stable using prednisolone for 3 months. She was diagnosed with B-cell lymphoma of the right middle ear after otoscopic sampling, which showed evidence of the filling of bilateral tympanic bullae on computed tomography. Hepatic involvement was suspected, and she was treated with multidrug chemotherapy, resulting in clinical remission. On day 176, magnetic resonance imaging and computed tomography were performed at checkup, revealing tumor invasion into the nasopharyngeal region and the recurrence of hepatic lesions without any brain abnormality. Nasal congestion then worsened, and the patient died on day 228 after presenting with generalized seizures. Clinicians should be mindful of middle ear lymphoma as a differential diagnosis in cats who present with a sign of otitis media, especially whose condition does respond to corticosteroid treatment. The prognosis for feline middle ear lymphoma might not be as poor as previous reports, and multidrug chemotherapy might result in remission of the disease.