Comparative Neuromuscular Laboratory

Long-term Follow-up of a Corgi with Polymyositis and Tongue Atrophy

Contributed by Dr. Miyoko Saito Azabu University Sagamihara, Kanagawa, Japan

Clinical History

A 5 year old female Pembroke Welsh Corgi (PMC) was presented for tongue atrophy beginning at 1 year of age. Clinical signs progressed to include masticatory muscle atrophy, tremor of all four limbs and exercise intolerance at 2 years of age, facial paralysis at 3 years of age, and finally pharyngeal and laryngeal paralysis at 5 years of age. The dog had been doing relatively well for several years.

Fig. 1A. H&E stain frozen muscle biopsy

Fig. 1B. SDH reaction

Long-term Follow-up

The diagnosis was made in this case by the characteristic clinical signs and detection of autoantibodies against the cross striations of skeletal muscle in serum (reported in Toyoda 2010). Other than muscle fiber loss, biopsies of the tongue and quadriceps muscles were reported to be unremarkable. This is not unusual given the fact that inflammatory myopathies can have a patchy or multifocal distribution and be missed on individual biopsy specimens. Clinical signs were moderately responsive to cyclosporine and prednisolone. Pharyngeal and laryngeal paralysis, and exercise intolerance, improved. Muscle atrophy was still prominent and did not resolve. The dog died due to an unrelated disease at 8 1/2 years of age. This clinical presentation has been found in several PMC in Japan and previously reported (Toyoda et al. Inflammatory myopathy with severe tongue atrophy in Pembroke Welsh Corgi dogs. J Vet Diagn Invest 2010;22:876-885)..