Presumptive diagnosis of high‐grade multicentric lymphoma in a paraparetic cat from focal conjunctival mass sampling

Abstract

An 11‐month‐old, neutered, male Maine Coon cat presented with paraparesis, anorexia, lethargy, pain and difficulty defecating. A computed tomography scan 10 days after initial signs revealed alveolar hyperattenuation, but no spinal lesions. Magnetic resonance imaging 15 days post‐onset revealed two well‐defined, extra‐axial, plaque‐like mass lesions in the brainstem and right parietal region, associated with focal bone changes. Additional findings included a multifocal, intra‐medullary lesion causing hyperesthesia of the mid‐caudal thoracic spinal cord, enlarged lymph nodes and a tubular T2w/STIR hyperintense structure near the liver and gall bladder. Cerebrospinal fluid analysis was inconclusive. A conjunctival mass was noted, and fine‐needle aspiration confirmed large cell lymphoma. The cat received oral lomustine without neurological improvement and was euthanased 18 days later due to progressive clinical decline. This case highlights large cell lymphoma as a differential for feline neurological dysfunction, regardless of age, chronicity, breed or viral status.