Clinical and histological features of primary progressive, familial thyroiditis in a colony of borzoi dogs.

A six-year study of clinical data and the morphologic changes involved in lymphocytic thyroiditis in a colony of related borzoi dogs was conducted. Lesions observed included initial degenerative thyroidal parenchymal changes which progressed to subacute inflammation with subsequent fibrosis and end stage thyroid gland disease. This study encompasses three successive generations of this borzoi colony and documents the progression of the histologic changes from the initial thyroid gland degenerative lesions to the end stage parenchymal atrophy. Spontaneous, familial thyroiditis has not been reported previously in the borzoi breed.