A. Gauffenic (1) ; V. Ratsimbazafy (2) ; F. Lioté (3) ; A. Linglart (4) ; E. Bourrat (5) ; Al. Fauchais (6) ; Hk. Ea (1) ; V. Guigonis (7)

(1) Federation Of Rheumatology, Lariboisière Hospital, Paris; (2) Pharmacy Department, University Hospital, Limoges; (3) Rheumatology, Paris Diderot University, Lariboisière Hospital, Paris; (4) Pediatric Endocrinology-Diabetology Department, Bicêtre University Hospital , Le Kremlin-Bicêtre; (5) Dermatology, Saint Louis Hospital, Paris; (6) Internal Medicine, Limoges University Hospital , Limoges; (7) Pediatric Department, Limoges


INTRODUCTION: Ectopic calcifications and ossifications form in non-mineralized tissues, most often in cutaneous, subcutaneous, muscular or peri-articular tissues. Local and systemic inflammatory flares are complications that cause severe disability. Among the proposed medical treatments, the systemic administration of sodium thiosulfate (STS) gives promising results but is difficult to use in clinical practice.

OBJECTIVE: evaluate the efficacy and safety of topical STS in ectopic calcifications or ossifications.

METHODS: Retrospective, non-randomized, open-label, multi-center study involving 4 centers (1 adult rheumatology, 2 pediatric and 1 internal medicine departments). Participants gave their informed signed consents. Patients with calcification or ossification were treated for at least 6 months with 25% TSS masterly prepared by the pharmacy of the hospital of Limoges (France).

RESULTS: Out of 126 patients who received STS 25%, 35 had complete clinical and radiographic data for analysis. There were 18 children (mean age 8.9 years) and 17 adults (mean age 52.4 years). Calcifications or ossifications were due to dermatomyositis (8 children, 6 adults), scleroderma (0 children, 6 adults) or pseudo-hypoparathyroidism 1A (7 children, 0 adults). They were single (37.1%) or multiple (62.9%). Treated regions were located in the lower limbs (31.4%), upper limbs (25.7%), both limbs (28.6%) and distal extremities (11.4%). Topical STS was clinically effective in 31.4% of patients, allowing radiographic size reduction of the treated calcifications. Three patients had a complete disappearance of their calcifications. The therapeutic response was more frequently observed in children (44.0% vs. 17.6%, p=0.056). There was no difference between responders and non-responders in terms of gender, age, causal disease, associated treatments and location of calcifications. Topical STS was well tolerated.

CONCLUSION: Local STS appears to be effective, particularly in pediatric calcifications or ossifications. Randomized and experimental studies are needed to identify its mechanisms of action.

Keywords: ectopic calcinosis, ectopic ossification, sodium thiosulfate, topical treatment, radiographic evaluation.