Severe Deforming Ollier Disease with a Giant Proximal Humeral Benign Chondroid Lesion in an Adolescent Male: Case Report.

Introduction: Ollier disease is a rare sporadic enchondromatosis characterized by multiple asymmetrically distributed enchondromas, progressive skeletal deformity, and risk of malignant transformation. Case Report: A 16-year-old boy presented with severe childhood-onset multifocal appendicular deformity, short stature, dysmorphic facies, developmental delay, and a giant left proximal humeral lesion that raised concern for secondary chondrosarcoma. The first swelling was noticed over the left hand at about 3 months of age, followed by progressive asymmetric lesions involving the upper limbs, pelvis, femora, tibiae, knees, and hands. Examination showed multiple hard, non-tender bony swellings, restricted shoulder movement, limb-length inequality, angular deformity, and gait disturbance. Serial radiographs demonstrated widespread expansile intramedullary chondroid lesions with cortical expansion and progressive deformity. Because of the interval enlargement of the shoulder lesion, pediatric, genetic, endocrine, and surgical oncology opinions were obtained. Ultrasound-guided core biopsy showed hyaline cartilage without increased cellularity, cytological atypia, or mitotic activity, favoring a benign chondroid lesion. Molecular testing was advised, but could not be performed because of financial constraints. The patient was managed with non-steroidal anti-inflammatory drugs, physiotherapy, and surveillance. Conclusion: At 6 months, he reported symptomatic improvement, and at 1 year, there was no documented clinical progression. This case highlights the diagnostic complexity of severe enchondromatosis, the value of longitudinal imaging review and biopsy of suspicious lesions, and the practical role of multidisciplinary surveillance when advanced molecular testing is not feasible.