Familial tumoral calcinosis in two Chinese patients: a case series

The value of perforator flap reconstruction in painful soft tissue calcifications

Soft tissue calcifications frequently cause debilitating pain and functional impairments, considerably affecting patients' quality of life. As they are rare entities, evidence remains sparse, especially regarding treatment effectiveness and recurrence rates. While both pharmacological and surgical treatments may alleviate symptoms, complete resection is currently believed to prevent long-term recurrence of deposits. To improve understanding and raise awareness for soft tissue calcifications, the goal of this study was to review the current state of treatment and to compare benefits and possibilities of flap reconstruction versus simple excision in improving quality of life. Furthermore, we include a successful case report of complete resolution of symptoms following quadruple perforator flap reconstruction. By systematic literature review, studies published in MEDLINE between 1980 and 2024 reporting on surgical treatment and outcome of soft tissue calcifications were included, in addition to a detailed description of our case report. A total of 53 studies reporting on 197 patients with soft tissue calcifications were included. Simple surgical excision was the most commonly (85.9%) employed procedure, demonstrating a substantial recurrence rate of 13.3%. In contrast, no patients who underwent radical excision experienced recurrence. Dermal matrix grafts and flap reconstruction were successfully used in patients requiring substantial tissue coverage, highlighting their value in complex defect reconstruction following radical excision. The combination of complete surgical resection and flap reconstruction reduces recurrence rates and improves postoperative outcomes and quality of life of these patients, supporting early radical surgical intervention as the gold standard treatment for soft tissue calcifications.

A novel FGF23 mutation in hyperphosphatemic familial tumoral calcinosis and its deleterious effect on protein O-glycosylation

BACKGROUND

Hyperphosphatemic familial tumoral calcinosis (HFTC) is a rare disease characterized by hyperphosphatemia and ectopic calcification, predominantly at periarticular locations. This study was performed to characterize the clinical profile of tumoral calcinosis and to identify gene mutations associated with HFTC and elucidated its pathogenic role.

METHODS

The three subjects (two male and one female) were aged 30, 25 and 15 years, respectively. The clinical features, histopathological findings, and outcomes of three subjects with HFTC were retrospectively reviewed. The three subjects were analyzed for FGF23, GALNT3 and KL mutations. Function of mutant gene was analyzed by western blotting and wheat germ agglutinin affinity chromatography.

RESULTS

All subjects had hyperphosphatemia and elevated calcium-phosphorus product. Calcinosis positions included the left shoulder, left index finger, and right hip. Bone and joint damage were present in two cases and multiple foci influenced body growth in one case. The histopathological features were firm, rubbery masses comprising multiple nodules of calcified material bordered by the proliferation of mononuclear or multinuclear macrophages, osteoclastic-like giant cells, fibroblasts, and chronic inflammatory cells. The novel mutation c.484A>G (p.N162D) in exon 3 of FGF23 was identified in one subject and his family members. Measurement of circulating FGF23 in the subject confirmed low intact FGF23 and increased C-terminal fragment. In vitro experiments showed that the mutant FGF23 proteins had defective O-glycosylation and impaired protein proteolysis protection.

CONCLUSION

We identified a novel FGF23 missense mutation, and confirmed its damaging role in FGF23 protein O-glycosylation. Our findings expand the current spectrum of FGF23 variations that influence phosphorus metabolism.