Background: This study aims to investigate isocitrate dehydrogenase gene mutations in patients with the non-hereditary skeletal disorders of Ollier disease and Maffucci syndrome, particularly in the extraosseous tumours. Methods: A total of 16 tumours from three patients with Ollier disease and three patients with Maffucci syndrome were collected. Sanger sequencing was applied to determine the hotspot mutations of IDH1 and IDH2 genes in multiple neoplastic tissues. Results: A majority of the tumours displayed an IDH1 mutation (p.R132C in 11 tumours including the paediatric ovarian tumour from one patient with Ollier disease, 4 cutaneous haemangiomas from three patients with Maffucci syndrome, 5 enchondromas and 1 chondrosarcoma; p.R132H in 2 cartilaginous tumours from one patient). Conclusions: IDH1 mutations were demonstrated in multiple cartilaginous tumours and extraskeletal neoplasms in this case series. Specifically, identical IDH1 mutations were confirmed in the separate lesions of each patient. These results are in concordance with findings that have been reported. However, here, we additionally reported the first case of Ollier disease with an ovarian tumour, which harboured the identical IDH1 mutation with the corresponding cartilaginous tumour. We further provided evidence that IDH mutations are the potential genetic links among the multiple neoplastic lesions of Ollier disease and Maffucci syndrome.

Background: The clinical utility of postoperative radioiodine ( ¹³¹ I) ablation remains unclear for patients with initially diagnosed non-distant metastatic papillary thyroid carcinoma (PTC) with harboring TERT promoter(TERT-p) mutations, it is unknown whether ¹³¹ I therapy reduces the risk of persistent or recurrent disease. This study investigated clinicopathological features, 2-year dynamic therapeutic responses and progression-free survival (PFS) in this specific patient cohort. Methods: A single-center retrospective cohort study enrolled 113 eligible patients, allocated to the ¹³¹ I ablation group (n=62) and non- ¹³¹ I group (n=51). Two-year dynamic risk stratification assessed treatment response. Kaplan–Meier curves and Cox regression models were used for survival analysis. Results: The predominant TERT-p variant was C228T (89.4%), and most patients carried concurrent BRAF ^V600E mutations. Only initial surgical approach remained an independent intergroup variable. Within 2 years, 46.0% achieved acceptable responses, associated with sex and primary surgery (p=0.036,p < 0.001). High baseline ATA risk was strongly correlated with structural residual lesions and unfavorable therapeutic response (p < 0.001).No significant between-group differences in response were observed across all ATA risk subgroups. The median follow-up was 4.6 years; 3- and 5-year PFS rates were 67.5% and 39.1%. Age ≥55 years, N1b stage and high baseline ATA risk were independent adverse predictors of PFS. Both 2-year therapeutic response and PFS at the end of follow-up exhibited no statistical differences between the ¹³¹ I group and non- ¹³¹ I group. Conclusions: In this retrospective observational cohort, postoperative ¹³¹ I ablation was not associated with improved PFS among patients with non-distant metastatic TERT-p-mutant PTC. Advanced age, N1b lymphatic metastasis and high baseline ATA risk independently predict poor outcomes. Biologically, TERT-p mutations induce tumor dedifferentiation and impaired iodine uptake, diminishing ¹³¹ I efficacy. Clinically, routine ¹³¹ I yields no survival benefit for this high-risk molecular subgroup, guiding individualized surveillance and avoiding redundant ¹³¹ I exposure.