A rare coexistence: Ollier disease and primary hyperparathyroidism-mere coincidence or expanding the spectrum of Ollier disease?

Ollier disease (OD) is the most common form of multiple enchondromatosis. It is an extremely rare disorder characterized by the development of multiple benign cartilaginous tumors, known as enchondromas. The prognosis is mainly determined by the risk of malignant transformation, which occurs in approximately 50% of patients within the first 30 yr of life. The disease is caused by somatic gain-of-function mutations in the and genes, identified in around 80% of cases of enchondromas and chondrosarcomas. Primary hyperparathyroidism (PHPT) is a common endocrine disorder characterized by excessive secretion of PTH, resulting in dysregulation of calcium levels. It predominantly affects postmenopausal women and may result in complications, primarily involving the bones and kidneys, such as fractures and nephrolithiasis. We report the first case of a patient with OD in whom PHPT was diagnosed and associated with the presence of an mutation detected in a parathyroid adenoma. This observation suggests a possible role of mutations in parathyroid tumorigenesis in OD and underscores the need to consider endocrine manifestations in this condition.KEYWORDSIDH1, IDH2, Maffucci syndrome, Ollier disease, multiple enchondromatosis, primary hyperparathyroidism© The Author(s) 2026. Published by Oxford University Press on behalf of the American Society for Bone and Mineral Research.