Tumoral calcinosis occurs when a large amount calcium salts deposit into the soft tissues. The calcium deposition is considered heterotopic, but it is neither ossification nor osteoid matrix formation. The calcifications are separate from bone.

Large amounts of periarticular calcinosis may occur as a result of:

• renal failure
• secondary hyperparathyroidism

or it may be idiopathic in younger people.

A differential diagnosis includes:

• hydroxyapatite deposition disease (HADD)
  • may appear similar, but is limited to a small focus in a tendon or a bursa
• bone forming tumor with osteoid matrix (e.g. parosteal osteosarcoma)
• a wide variety of soft tissue masses with calcification, both benign and malignant

Renal failure appeared to be the precipitating factor for the development of the tumoral calcinosis in this case.