A Rare Coexistence: Ollier Disease and Primary Hyperparathyroidism—Mere Coincidence or expanding the spectrum of Ollier Disease?

Abstract Ollier disease 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 IDH1 and IDH2 genes, identified in around 80% of cases of enchondromas and chondrosarcomas. Primary hyperparathyroidism is a common endocrine disorder characterized by excessive secretion of parathyroid hormone, 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 Ollier disease in whom primary hyperparathyroidism was diagnosed and associated with the presence of an IDH1 mutation detected in a parathyroid adenoma. This observation suggests a possible role of IDH1 mutations in parathyroid tumorigenesis in Ollier disease and underscores the need to consider endocrine manifestations in this condition.