SAT-797 - Tumoral Calcinosis: The Mayo Clinic 30-Year Experience

Tumoral calcinosis (TC) is a rare disorder characterized by calcium-phosphate complex deposition in periarticular tissues. While TC can occur secondary to rheumatological conditions or renal dysfunction, familial disease is caused by mineral metabolic derangements, often linked to genetic mutations. We conducted a retrospective chart review of patients diagnosed with TC between 1995 and 2025, in the absence of kidney disease or rheumatologic conditions. Data were extracted from the electronic medical record.
A total of 521 patients were initially identified, and 474 were excluded after screening. The final cohort consisted of 47 patients, with a median age at diagnosis of 58 years (IQR 40-70); 85.1% were female and 80.9% were Caucasian. The most common presenting symptom was painful periarticular masses (78.7%), with frequent involvement of shoulders (25.5%), elbows (25.5%), hips (23.4%), hands (21.3%), and feet (17%). Extra-skeletal involvement occurred in sixteen patients (34%), primarily in the skin in 15 patients (93.8%) and vascular system in 4 patients (12.5%). Thirteen patients (27.7%) were hyperphosphatemic. Six patients underwent genetic testing, with GALNT3 being the most common abnormality identified (33.3%). Thirty-five patients underwent surgical intervention, most commonly to relieve pain (17/35). Six patients had pathology reports with mention of the presence of “giant cells”. Out of the patients who underwent surgery, 28.6% experienced recurrence of their lesions, with a median time to recurrence was 19 months (IQR 11-36). Sixteen patients (34%) received dedicated medical treatment; in hyperphosphatemic patients, a low-phosphorus diet and phosphate binders were the most frequently used therapies and were the most effective in lowering phosphate levels and improving radiologic findings.
Compared with prior reports, our cohort had a higher proportion of Caucasian patients, whereas most published studies report greater prevalence in subjects of African descent. This discrepancy may reflect a referral bias, geographic differences or the heterogenicity of this disease. Smaller joints, particular the hands and feet, were more frequently involved in our cohort compared to what is reported in the literature. Despite surgical intervention, recurrence rates remained substantial, emphasizing the limitations of current management strategies. The presence of giant cells in several pathology specimens suggests a possible inflammatory component, which could be a future therapeutic approach beyond the standard phosphate-lowering strategy. Overall, our single-center experience underscores the heterogeneity of this disease and the need for further treatment strategies. Larger studies and consensus guidelines are warranted to define prognostic factors and therapeutic outcomes.

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