Multiple Cutaneous Metaplastic Ossification Associated with Iatrogenic Hyperglucocorticoidism

20 Other generalized signs reported in affected animals include polydipsia, polyuria, muscle weakness, hepatomegaly, and myopathies. Although calcinosis cutis in its broadest definition can encompass all forms of calcium deposition, it is most commonly used to denote the specific pattern of dystrophic calcification associated with hyperadrenocorticism or iatrogenic hyperglucocorticoidism. 8 The mechanism of this process has not been completely elucidated, but it involves phase transformation of calcium and phosphate ions from solution into crystalline aggregates, with deposition upon the matrices of dermal collagen and elastin under the influence of cellular factors. 3,8 The collagen fibers in these cases are variably mineralized, and root sheaths may also be affected. 8,20 The deposition of minerals in calcinosis cutis is often not associated with areas of inflammation and, when observed, typically consists of a histiocytic foreign-body-type reaction. In contrast, several dermatologic conditions of humans known as metaplastic ossification, primary or secondary osteoma cutis, plate-like osteoma, and acquired cutaneous osteomatosis are characterized by metaplastic bone formation in the dermis, where osteoid formation occurs with or without collagen mineralization. 2,4,7,10,12,15,18 Some of these syndromes are id