Pediatric Hand Cyst with Metacarpal Bone Changes: An Embedded Tree Thorn Case.

Introduction: Retained foreign bodies in pediatric hand injuries are rare but can lead to significant complications if undiagnosed. Organic foreign bodies, such as tree thorns, are often radiolucent and may not be detected on plain radiographs, making diagnosis challenging. This case highlights the importance of considering a retained foreign body in a child presenting with a persistent hand mass and associated bony changes. Case Report: A 3-year-old male presented with a painless, slow-growing mass over the dorsal ulnar aspect of his left hand for 8 weeks. Clinical examination revealed a fluctuant, non-tender mass without overlying skin changes. Radiographs showed a periosteal reaction with a lytic lesion on the metacarpal bone, and ultrasonography revealed a hyperechoic foreign structure within a cystic collection. The patient underwent surgical removal of the foreign body and debridement. Intraoperatively, a conical tree thorn measuring 1.0 cm was identified and removed. Post-operative recovery was uneventful, and the patient showed complete resolution of symptoms. Histopathology confirmed a foreign body granulomatous reaction. Conclusion: Organic foreign bodies should be considered in pediatric hand masses with associated bony changes. Ultrasonography plays a crucial role in diagnosis, particularly when radiographs are inconclusive. A multidisciplinary approach, including imaging, surgical intervention, and postoperative care, ensures optimal outcomes.