Diffuse, subcutaneous presentation of neurolymphomatosis in a horse with multicentric lymphoma

Abstract

SummaryA five‐year‐old Dales gelding was presented with an eight‐week history of progressive, apparently nonpainful, cord‐like, subcutaneous masses across the face, neck, trunk and forelimbs. Physical and neurological examinations identified mild, diffuse weakness, hyperaesthesia and moderate tachycardia. Transcutaneous and transrectal ultrasonography and endoscopy of the guttural pouches confirmed marked enlargement of peripheral nerves and visible cranial nerves, respectively. Histopathology of the subcutaneous lesions was indicative of chronic lymphoplasmacytic polyneuritis with fibrosis. The horse failed to respond to treatment with glucocorticoids, showing progressive generalised weakness and was euthanised. Post‐mortem examination identified a generalised lymphadenopathy and widespread dissemination of neoplastic lymphocytes, throughout the peripheral and central nervous system, heart and liver, identified by immunohistochemistry as T‐cell rich B‐cell lymphoma. This is the first report in the veterinary literature of diffuse neurolymphomatosis presenting as visible branching subcutaneous masses.