A broken mercury thermometer in the orbital cavity

INTRODUCTION: Elemental mercury exposure is an important public health concern. Direct soft tissue exposure to mercury is rare and can lead to local inflammatory reactions and complications if not promptly addressed. CASE SUMMARY: We report a 4-year-old boy with a foreign body intrusion to the left periorbital region after he fell onto a glass mercury thermometer. The thermometer head, containing elemental mercury, was embedded beneath the lower eyelid skin. Initial symptoms were minimal, but two months later, the patient developed swelling and a palpable mass. Fibrous tissue, glass, and leaked elemental mercury were surgically removed to minimize complications caused by mercury dissemination, such as granuloma or sterile abscess formation. IMAGES: The mass moved with eye movements. Skull radiographs revealed a linear distribution of mercury around the orbit. Surgery was performed to remove the mercury. Histopathology showed lymphocytic infiltration around mercury droplets, indicating localized inflammation. At three-month follow-up, there were no residual abnormalities. CONCLUSION: This patient highlights the importance of recognition and surgical management in periorbital mercury exposure. Precise removal may prevent complications.