True grit: the tale of a subcutaneous mass in a dog

A 14-month-old, intact, male German Shepherd dog was referred for a 6 x 3-cm, firm mass in the left pelvic limb. Fine needle aspiration yielded chalky white material. May-Grünwald-Giemsa-stained smears showed a uniform background of amorphous, poorly stained, light-blue material and scattered foamy macrophages, a few naked nuclei, and cellular debris. The cytologic diagnosis of calcinosis circumscripta was confirmed by histologic evaluation of the surgically removed mass. In this report, we document the unique cytologic and histologic patterns of this uncommon tumor-like lesion.