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.