Proposal for a Pathogenesis‐based Classification of Tumoral Calcinosis

Abstract

A classification for tumoral calcinosis is devised that outlines potential pathogenetic mechanisms and predicts response to therapy and prognosis. Analysis of other forms of calcinosis cutis may reveal definable pathogenetic differences that suggest a coherent classification for all cutaneous calcinoses.

Hyperphosphatemic familial tumoral calcinosis caused by a mutation in GALNT3 in a European kindred

“…It is often associated with hyperphosphatemia (Smack et al 1996), and is then termed hyperphosphatemic familial tumoral calcinosis (HFTC; MIM211900). HFTC has been shown to result from loss-of-function mutations in at least two genes: GAL-NT3 coding for UDP-N-acetyl-alpha-D-galactosamine: polypeptide n-acetylgalactosaminyltransferase 3 (ppGalNacT3) (Topaz et al 2004;Ichikawa et al 2005), a glycosyltransferase, which initiates O-glycosylation (Ten Hagen et al 2003);and FGF23 (Benet-Page`s et al 2005;Larsson et al 2005;Araya et al 2005;Chefetz et al 2005) coding for fibroblast growth factor 23 (FGF23), a potent phosphaturic protein (Berndt et al 2005).…”

Tumoral Calcinosis

“…However some authors have postulated that an inborn error of phosphorus metabolism relating to abnormal phosphate reabsorption and 1,25-dihydroxyvitamin D formation in the proximal renal tubule may be the likely aetiology [4]. There are two distinct subtypes of idiopathic tumoral calcinosis [5], namely primary normophosphataemic tumoral calcinosis in which the patient has normal serum phosphate and calcium levels and primary hypophosphataemic tumoral calcinosis in which the patient has elevated serum phosphate levels with normal serum calcium. Patients with tumoral calcinosis typically present with painless masses in juxta-articular locations, at hip, knee and elbow joints although the shoulder, hands and feet can be involved.…”

Spinal cord compression due to tumoral idiopatic calcinosis

“…1,4,6,7 In a review by Smack et al, 3 121 cases of TC were identified. They suggest three pathogenetically distinct subtypes: (1) Primary normophosphatemic TC without metabolic abnormalities, with no evidence of familial Until the present date, in only two reports has TC been pointed out as the cause of spinal cord compression.…”

“…1,2 Little is known about the exact etiology and several hypotheses have been suggested. [1][2][3][4] Spinal involvement is rare, and to the best of our knowledge, TC of the thoracic spine has been reported only once before. 5 We describe an exceptional case of a patient with paraparesis caused by TC located in the thoracic spine, which was totally resected.…”