Abstract
INTRODUCTION: Osteolytic lesions in the long bones of the upper and lower limbs in early childhood can arise from various conditions, ranging from benign cysts to malignancies. While malignant neoplasms are often suspected, benign conditions like Langerhans cell histiocytosis (LCH) can present similarly. We report a rare case of an 11-month-old girl with a solitary osteolytic lesion in the distal radius, which was diagnosed as LCH. The unusual combination of age, location, and presentation provides new insights into the management of LCH in infants. CASE REPORT: An 11-month-old girl presented with a 5-day history of pain and bony swelling in the right forearm, with no history of trauma or fever. Examination revealed localized swelling and tenderness over the distal radius, with normal skin and joint mobility. Inflammatory markers were mildly elevated. Radiographs and magnetic resonance imaging revealed an expansile lytic lesion of the distal radius. Biopsy showed histiocytes, multinucleated giant cells, and eosinophils, with Immunohistochemistry (S100+, CD1a+, Langerin+, CD68+) confirming LCH. Positron emission tomography-computed tomography revealed no systemic involvement. Curettage followed by an intralesional injection of methylprednisolone (40 mg/mL) was performed. At 2-year follow-up, radiographs showed no recurrence, with excellent healing. CONCLUSION: LCH is a rare cause of solitary osteolytic lesions in children. Curettage with intralesional steroids can achieve complete resolution with minimal recurrence.