Multiple Cutaneous Metaplastic Ossification Associated with Iatrogenic Hyperglucocorticoidism

Abstract

Characteristic dermatologic lesions of naturally occurring and iatrogenic canine hyperglucocorticoidism have been well documented, and include any combination of bilaterally symmetric alopecia, thinning of the epidermis, skin hyperpigmentation or depigmentation, comedones, phlebectasia, and calcinosis cutis. 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 idiopathic, while others have been associated with a variety of predisposing factors, including acne vulgaris, systemic metabolic illness, dermal surgery, and chronic irritation. 1,12,15,17,18 Reported here are 2 cases of widespread dermal osseous metaplasia in dogs with evidence of iatrogenic hyperglucocorticoidism that share histologic features with human cases of metaplastic ossification.An 8-year-old male Rottweiler had a 4-year history of chronic skin disease that was only partially responsive to antibiotic and corticosteroid therapy and was becoming progressively worse. The dog was minimally pruritic. On physical examination, moderate multifocal areas of alopecia and lichenification were observed on the dorsal topline with extension to the neck, shoulders, hips, and proximal limbs. Six separate, oozing, variably sized dermal ulcers were present along the back from the shoulder blades to the area near the base of the tail. Numerous pustules, macules, and papules were distributed along the skin of the back, and the skin was noticeably thickened. Multiple skin scrapings and dermatophyte cultures were negative, and complete blood counts were within normal limits. Serum chemistry abnormalities Received for publication May 13, 1997.(normal ranges given in parentheses throughout) included 901 U/liter (Ͻ141 U/liter) alkaline phosphatase and 258 U/ liter (Ͻ85 U/liter) ALT. The urine specific gravity was 1.0...

Calcinosis cutis in dogs: histopathological and clinical analysis of 46 cases

“…Osteoma cutis was seen in the majority of dogs with pituitary‐dependent hyperglucocorticism and a smaller percentage of dogs with iatrogenic hyperglucocorticism in this study, which has been recognized previously …”

“…Osteoma cutis was seen in the majority of dogs with pituitary-dependent hyperglucocorticism and a smaller percentage of dogs with iatrogenic hyperglucocorticism in this study, which has been recognized previously. 2,20 Polarizing microscopy and infrared spectrometry identified the deposited minerals as apatite in formalin-fixed tissues of three dogs with CC associated with different underlying diseases. The lack of identification of apatite in the fourth sample, from a dog with an unknown underlying disease, may be due to the small size of the available sample, because no mineral was found.…”

Metaplastic ossification of a cervical sialocoele in a dog

“…There is overrepresentation of German Shepherds in ectopic ossification and mineralisation syndromes, and a genetic predisposition may be postulated. 31 Trauma 9,16 and chronic inflammation 14,15,18,19 have been incriminated in the development of ectopic ossification in various cases in dogs. In the present case, a possible genetic predisposition for metaplastic ossification was manifested after trauma (either the inciting cause or original lancing) or by contact with inflammatory cells arising from chronic inflammation of the affected salivary gland.…”

“…9 Extraosseous non-neoplastic growth of new bone in various sites (ectopic ossification) has been infrequently reported in this species. [10][11][12][13][14][15][16][17][18][19] Osteosarcoma 20 and mixed tumour ossification 21 of the mandibular salivary gland in the dog have both been reported. In this paper, a unique case of metaplastic ossification of a cervical sialocoele in a dog is presented.…”

Primary isolated osteoma cutis causing eyelid deformation and strabismus in a dog

“…Heterotopic ossification is the formation of bone outside the skeletal system. It can occur in a variety of soft tissues including skeletal muscle, ligaments, blood vessel walls, and skin When heterotopic ossification occurs in skin, it is referred to as osteoma cutis and it is rarely diagnosed in both human and veterinary medicine . Osteoma cutis is classified as primary or secondary based on the underlying pathogenesis of the bone formation.…”