Mineralizing Pulmonary Elastosis in a Cat

Abstract

Mineralizing pulmonary elastosis (MPE) is a rare and unique phenomenon that has been reported in humans, typically secondary to recurrent pulmonary haemorrhage. MPE has a complex histopathological appearance, often containing iron-calcium deposits that can be mistaken as fungal organisms or other inorganic material. This report documents the first case of MPE in an animal species. A 10-year-old female domestic cat with respiratory failure was submitted for necropsy. The lungs were consolidated with severe pulmonary haemosiderosis, and widely disseminated granulomas surrounded large aggregates of hyphae-like structures. The pulmonary vasculature and airway smooth muscle were partially mineralized and fragmented. Histochemical stains revealed that the fungus-like material stained strongly with Prussian blue and alizarin red but only sparingly with von Kossa and negative with Gomori's methenamine silver stain. These findings are similar to those of MPE in humans. As most veterinary pathologists may not be familiar with MPE, it is important to avoid possible misinterpretation by recognizing its distinct features and the ancillary testing that may be required.