A really lively 6 year old male Labrador with a history of insidious onset intermittent non weight bearing right thoracic limb lameness that was exacerbated with exercise and poorly responsive to NSAIDs. Orthopaedic examination found repeatable pain on flexion of the carpus. No other abnormalities were found. Radiographic images of the carpus were unremarkable. An MRI of the carpus found clear evidence of soft tissue abnormality in the palmar part of the right carpus. The pathology appeared to be within the region of the flexor retinaculum and the ulnar neurovascular bundle and the adductor muscle of digit 5. The DDFT and SDFT tendons themselves appeared normal. The pathology seemed to be in the region of the ulnar nerve. Compression of the ulnar nerve by soft tissue injury in this region in man is part of carpal tunnel syndrome, and was thought to be the cause of the lameness in this case. A mass within the nerve itself could not be excluded in the MRI study.
Given the location of the lesion and the difficulties in procuring biopsy material, a surgical exploration of the right carpal canal was made via a lateral approach. Gross swelling of the ulna nerve was observed as it coursed through the carpal canal.
The mass was excised with a 2-3cm margin proximally and distally and submitted for histopathology.
Histopathology confirmed the mass was a Peripheral Nerve Sheath Tumour which had a proximal clear margin of 10mm and a distal clear margin of 30mm. Recovery from surgery was uneventful and the following videos show how Chumley recovered. Currently, I am pleased to report, he is over 2 years post surgery, free from lameness and with no evidence of recurrence.