Lincoln sign on bone scintigraphy

Lincoln sign on bone scintigraphy (also known as black beard sign) is one of the signs of Paget disease on the radionuclide bone scan when the disease involves the mandible. The sign might be seen when the extensive mandibular involvement with Paget disease results in the uptake of the radiotracer from one mandibular condyle to another mimicking a man with a black beard on the anterior view of the bone scan (as per the beard of Abraham Lincoln, 16th President of the United States).