Clinical and imaging features of a feline lumbar myelopathy resembling ossification of the posterior longitudinal ligament in humans

A 9-year-old, male, neutered Russian blue cat was presented for a 2-week history of pelvic limb weakness and reluctance to jump and climb stairs. Neurological examination was consistent with an L4-L6 myelopathy. Ectopic calcification of soft tissues within the vertebral canal involving the dorsal longitudinal ligament over the L5-L6 vertebrae was diagnosed based on radiography, magnetic resonance imaging and computed tomography. The lesion was surgically excised, and histopathological examination demonstrated fibrous connective tissue with calcification. The patient was neurologically normal 2 months after surgery, and no relapses have occurred in a follow-up period of 2 years. The findings in this case had not been previously reported in cats, and share some similarities with a clinical entity in humans named ossification of the posterior longitudinal ligament.