Ectopic Mineralisation

• Also called heterotopic mineralisation (calcification)
• Deposition of calcium phosphate, silicate and other in unusual locations
• Contrast with ectopic ossification
• Can be
  • Idiopathic
    • E.g. primary tumoral calcinosis (see below)
  • Metastatic
    • E.g. Associated with hypercalcaemia of uraemia and hypervitaminosis D
  • Dystrophic
    • E.g. due to repetitive trauma
• Calcinosis cutis
  • Associated with hyperadrenocorticism, exposure to calcium chloride and wet concrete
  • Also present in some normal poodles
• Calcinosis circumscripta (tumoral calcinosis)
  • Usually single lesion in skin of extremities of dogs
  • May occur in vertebral region and cause ataxia
  • In horses mainly 2-4 years old at lateral stifle, not attached to skin
  • May be the result of repetitive trauma (e.g. in supraspinatus tendon in hunting or working dogs)
  • Grossly:
    • Nodular masses about 1cm across or few cm more
    • May ulcerate
    • White, soft creamy or dry gritty on cutting
  • Microscopically:
    • Amorphous and granular mineralised areas
    • Surrounded by connective tissue
    • Granulomatous reaction is common
    • Chronic lesions may contain metaplastic cartilage or bone