Tumoral Calcinosis
Julie C. Fanburg-Smith, MD
Cyril Fisher, MD, DSc, FRCPath
Key Facts
Terminology
Extraskeletal soft tissue calcification with granulomatous response
Clinical Issues
Most cases < 20 years
Some familial
In subcutis around large joints
Macroscopic Features
Poorly defined, infiltrative, multilocular cyst
Microscopic Pathology
Amorphous granular material (hydroxyapatite crystals)
Surrounding histiocytes with granulation tissue in early stage
Later irregular calcification, calcospherites
 CT scan of knee in a patient with tumoral calcinosis shows amorphous, dense subcutaneous extraarticular calcification  . The differential diagnosis includes renal osteodystrophy and collagen vascular disease. |
 Multilocular cystic lesion of tumoral calcinosis demonstrates cysts separated by fibrous septa  . The cysts contain basophilic amorphous material with small foci of granular calcification  . |
TERMINOLOGY
Synonyms
Lipid calcinosis
Calcifying collagenolysis
Tumoral lipocalcinosis
Definitions
Extraskeletal soft tissue calcification with granulomatous response
ETIOLOGY/PATHOGENESIS
Etiology Theories
Inborn error of phosphorus metabolism
Associated Conditions
Hyperphosphatemia
Genetics
Most cases sporadic
Some familial
Autosomal recessive
Mutations in GALNT3, FGF23, or KL genes
Some hyperphosphatemic
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