A further case of medroxyprogesterone acetate associated with calcinosis circumscripta in the dog

Pathomorphological features of calcinosis circumscripta in a dog

A 19-month-old male German shepherd dog was presented with a hindlimb footpad mass. The mass was excised and histopathology was performed. Grossly, the cut section of the mass had multiple well-circumscribed nodules with a chalky appearance. Histopathologically, basophilic-stained calcium deposits of various sizes were distributed from dermis to subcutis, surrounded by epithelioid cells, multinucleated giant cells, and reactive fibroblasts. Myxoid metaplasia, calcium deposits in hair follicles, and psammoma-like bodies were also found. These histopathologic observations will greatly help to understand the pathogenesis of calcinosis circumscripta.

Progestins to control feline reproduction

Relevance:

The high fertility rate of cats means that methods to control feline reproduction are a requirement for cat breeders and pet owners, as well as for those involved in the management of feral cat populations. Progestins continue to be used to prevent queens from cycling, and also as an adjunct or alternative to surgical sterilization within trap–neuter–return (TNR) programs.

Evidence base:

A considerable body of information exists on megestrol acetate (MA) and medroxyprogesterone acetate (MPA), thanks to the many studies and case reports published in the scientific literature over the past 50 years documenting their clinical use in cats. Comparatively less is known about the use in cats of more recent progestins such as levonorgestrel, proligestone, delmadinone, chlormadinone and altrenogest.

Dosing, safety and efficacy:

Based on a combination of dose, frequency and duration of treatment, MA can be categorized into low (0.625 mg/kg/week for up to 30 weeks), medium (0.625 mg/kg q24h for 1 week or q48h for up to 2 weeks) and high (0.625 mg/kg q24h or q48h for several weeks, or weekly for months or years) dosages. Studies suggest that low dosages can be used relatively safely in cats, while higher dosages increase the risk and severity of adverse reactions. Early work showing that an oral MPA dosage of 0.01 mg/kg administered q24h for 12 months suppresses oestrus in queens effectively and safely has not been considered, and much higher MPA dosages (>6.25 mg/kg q24h) have been used in cats over the past 40 years.

Recommendations:

Progestins should always be used with caution. Using the lowest possible dosages, MA and MPA may, however, continue to be used safely in pet queens as well as (in conjunction with TNR programs) for the control of feral cat colonies. More recent progestins appear to be effective and safe, albeit their efficacy and safety need to be further investigated.

Metastatic calcinosis (including calcinosis cutis) in a young dog with multiple urinary tract abnormalities

Metastatic calcinosis associated with chronic renal failure and multiple urinary tract abnormalities was diagnosed in a 6-month-old Brittany spaniel that was presented with calcinosis cutis. This case report highlights the importance of skin as an indicator of systemic disease. The aetiopathogenesis of the four main types of tissue calcification is defined and discussed with an emphasis on metastatic calcinosis.

Calcinosis circumscripta in the dog: a retrospective pathological study

Calcinosis circumscripta is an uncommon syndrome of ectopic idiopathic, dystrophic, metastatic or iatrogenic mineralization characterized by deposition of calcium salts in soft tissues. This paper is a retrospective study of 77 canine cases. The age of dogs in the study varied from 4 months to 15 years and 55% were <1 year old, 74% <2 years old and 88% <4 years old. Several pure and mixed, typically large breed dogs were affected so that 28.6, 13 and 9% were German Shepherd, Rottweiler and Labrador Retriever respectively. The size of lesions varied from 2 mm to 13 cm in diameter but most lesions were between 0.5 cm and 3 cm in diameter. Lesions were solitary in 82% of the affected dogs, and occurred most commonly on the hind feet (50%) and tongue (23%). With multiple lesions there was no apparent body symmetry. Microscopically, most lesions were well-defined single or multiple variably sized aggregates of amorphous to granular, lightly to darkly basophilic material with or without peripheral granulomatous reaction and surrounded by varying amounts of fibrous connective tissue. Additionally, three small nodular masses in the wall of the jejunum of a dog were diagnosed as calcinosis circumscripta. This is the first reported case of idiopathic intestinal calcinosis circumscripta in the dog.

Metastatic calcinosis circumscripta treated with an oral charcoal absorbent in a dog

A five-year-old West Highland white terrier dog was admitted to the teaching hospital of Nippon Veterinary and Animal Science University due to swelling and pain of the foot pads. Examinations revealed that the dog had renal failure and calcinosis circumscripta on its foot pads. The diagnosis was metastatic calcinosis circumscripta secondary to renal failure. An oral charcoal adsorbent (Kremezin) was used to treat this condition. Following this treatment, a significant decrease in the Ca x P value (the serum calcium level x the serum phosphorus level) was observed, and the dog's condition improved dramatically. This case suggests that charcoal adsorbent (Kremezin) may be useful for treating metastatic calcinosis circumscripta in dogs.

Calcinosis circumscripta following an injection of proligestone in a Burmese cat

A 9-month-old speyed Burmese cat was presented with a cutaneous lesion in the dorsal thoracolumbar region. The lesion was characterised by alopecia and whitish deposits within the subcutis and had occurred at the site of a previous progestogen injection (Covinan; Intervet). Excisional biopsy confirmed the diagnosis of calcinosis circumscripta. Recovery of the cat following surgical excision was excellent, with no recurrence of the lesion detected 12 months later. The classification of tissue calcification and the proposed aetiology of calcinosis circumscripta is reviewed. It is concluded that further work is required to determine any link between subcutaneous injections, especially of progestogens, and calcinosis circumscripta.