Calcinosis circumscripta in a domestic short-haired cat.

A poorly circumscribed, subcutaneous mass present on the dorsum of a young mature, male domestic short-haired cat was diagnosed as calcinosis circumscripta. Histologically, the mass was composed of multiple, fragmented loculi with a crystalline, light red center surrounded by dense, amorphous, mineralized material. Loculi were separated by variably-dense bands of a connective tissue stroma. The cat was otherwise healthy, and the mass was excised without recurrence.