We present images of a 13-year-old boy with Gorham-Stout disease affecting the mandible. Initial bone scintigraphy showed poor visualization of 99mTc-methylene diphosphonate (99mTc-MDP) uptake in the mandible body. However, abnormally increased 99mTc-MDP uptake was noted in the bilateral mandibular rami. In the follow-up examination a year later, bone scintigraphy indicated that the disease had progressed to the bilateral mandibular rami with no uptake. In addition, massive osteolysis of the mandible was noted that had progressed since the initial computed tomography. This report suggests that bone scintigraphy could be a useful imaging tool to evaluate disease activity and determine treatment response.