Gorham disease is a rare condition characterized by intraosseous neoplastic proliferation of hemangiomatous tissue with progressive, massive osteolysis. We present a pathologically proved case of Gorham disease that involved the left parietal bone in a 23-year-old man. Imaging studies including conventional radiography of the skull, CT, MR imaging, and Technetium-99 m (Tc-99 m) scintigraphy demonstrated a large skull defect without associated soft tissue mass over the left parietal skull. Contrast enhancement and increased isotope uptake along the margin of the defect were shown at gadolinium-enhanced T1-weighted MR imaging and Tc-99 m methylene diphosphate (Tc-99 m MDP) bone scintigraphy. Pathologic study revealed intraosseous angiomatosis at the periphery of the osteolytic skull lesion.