Scintigraphic “Doughnut Sign” on Bone Scintigraphy Secondary to Metastatic Hepatocellular Carcinoma

A 57-year-old man noticed two bumps on the right fronto-parietal region of his head. Head CT showed an osteolytic lesion with soft tissue density in the right parietal bone. Tc-99m HMDP bone scintigraphy demonstrated a ring-like accumulation in the right parietal bone, and an area of increased uptake in the right temporal bone and at the left pedicle of the twelfth thoracic vertebral body. Abdominal CT scan was performed to look for a primary focus, and revealed numerous small round tumor lesions in the enlarged liver. Ga-67 citrate scintigraphy was performed for further confirmation and to look for metastatic foci, and showed an area of increased uptake in the calvarium, the twelfth thoracic spine, and the enlarged liver. Metastatic hepatocellular