Fibrotic myopathy of the iliopsoas muscle in a dog.

Fibrosis of the iliopsoas muscle can result in pelvic limb lameness in dogs. In this case report we describe fibrosis after an initial injury of the iliopsoas muscle in a dog. A seven-year-old hunting dog developed an acute onset of lameness and pain of the left pelvic limb after an intense period of exercise. Two months later, the dog was referred for evaluation of a non-weight-bearing left pelvic limb lameness. Orthopaedic examination revealed pain on hyperextension and internal rotation of the left coxofemoral joint. Neurological examination revealed a decreased patellar reflex in the left pelvic limb. Computed tomographic images showed non-uniform, contrast enhancement of the left iliopsoas muscle. The animal was treated with an iliopsoas tenomyectomy. Histopathological examination of the affected iliopsoas muscle revealed endomysial and perimysial mature fibrous replacement tissue. Sixteen weeks after surgery, the dog had returned to pre-injury levels of exercise.

Straelensiosis in dogs: a newly described nodular dermatitis induced by Straelensia cynotis.

A distinctive nodular dermatitis induced by Straelensia cynotis, a newly described trombidioid larval mite which resides in hair follicles, was identified in 12 dogs living in France. They all had scattered, small (1 to 3 mm in diameter), pale, firm skin nodules, variable in distribution but always affecting the dorsal regions of the head and trunk; they were distributed over the whole body of seven of the dogs. The animals were otherwise healthy except for three severely infested fox terriers which had a decreased appetite, were lethargic, and whose skin nodules were painful to the touch. The nodules did not induce pruritus. The lesions usually began as erythematous papules which developed into firm pale nodules. The dermatitis resolved within two to 12 months. Topical acaricides were ineffective but the skin nodules regressed after treatments with systemic avermectins. Histologically, each nodule was composed of a dilated follicular ostium containing a well-preserved larval mite, and showed a pseudoepitheliomatous follicular hyperplasia and an abundant perifollicular mucinosis. The larvae were identified as belonging to the genus Straelensia (Acari: Leeuwenhoekiidae). It was clearly established that the three fox terriers had become infested within a fox's den. The nymphs and adults of this species of mite are believed to live in foxes' dens; foxes are considered to be the natural host for the larval stage, and dogs a permissive but occasional host.