Radiographic characteristics of alveolar microlithiasis and pulmonary ossification following chronic corticosteroid therapy in a dog.

A 10-year-old, neutered female, Australian Shepherd was referred for acute respiratory distress and a history of chronic exogenous steroid administration. On thoracic radiographs, a severe increase in mineral opacity characterized as a generalized unstructured interstitial pulmonary pattern, diffuse calcinosis cutis, and moderate hepatomegaly were noted. Cor pulmonale was identified on echocardiography. The patient developed a pneumothorax following sampling and had a cardiac arrest. Postmortem histopathology of the lungs revealed pulmonary interstitial mineralization and alveolar microlithiasis. This report supports including generalized pulmonary mineralization due to chronic exogenous steroid administration as a differential diagnosis for dogs with these clinical and imaging findings.