Cytochemical detection of calcium in a case of calcinosis circumscripta in a dog.

A 9-month-old intact female Serra-da-Estrela dog (giant Portuguese breed) was presented with a 2-month history of lingual lesions. Two hard, nodular, nonpainful lesions were observed on the lateral border of the tongue. Fine-needle aspiration yielded a chalky white material. Hemacolor-stained smears showed an amorphous granular basophilic background with crystal-like structures and granulomatous inflammation consisting of foamy macrophages and giant cells. Cytochemical staining with von Kossa and Alizarin red S confirmed the calcareous nature of the material. The cytologic diagnosis was lingual calcinosis circumscripta; this was later confirmed by histopathologic examination. To our knowledge, this case is the first to document the use of von Kossa and Alizarin red S on cytologic smears to obtain a definitive diagnosis of lingual calcinosis circumscripta.