Inflammatory pseudotumour presenting as a cervical extradural mass in a 1-year-old Bernese Mountain dog

Abstract

A 1-year-old, male, neutered Bernese Mountain dog presented with a 2-week history of acute-onset progressive signs of right C6–T2 myelopathy and neck pain. Magnetic resonance imaging of the cervical vertebral column revealed a right-sided extradural mass at the level of the C6 vertebra causing severe spinal cord compression. A right C5–C7 modified dorsal laminectomy was performed to remove the mass, resulting in its complete excision, except for residual tissue attachments to the ligamentum flavum. Successful spinal cord decompression was achieved, as confirmed by postoperative magnetic resonance imaging. Histopathology and immunochemistry showed a proliferative lesion dominated by a mixture of spindle and histiocytic cells, with associated infiltrates of T-lymphocytes, B-lymphocytes and plasma cells suggestive of an inflammatory pseudotumour. Subsequently, the dog underwent a 2-month course of prednisolone treatment and showed complete recovery. At the 2-year follow-up, the dog was neurologically normal.