We report a case of post-Paget telangiectatic osteosarcoma of the skull in a 75-year-old woman. Such a neoplasia is a rare variant of osteosarcoma, a tumor rare in the cranic bones. The patient was submitted for a careful analysis by the following procedures: technetium scintigram, X-rays, CT scan, and MRI. After the surgical procedure, pathological examination confirmed the diagnosis. Both radiological and pathological pattern of this tumor are discussed in relation to the differential diagnosis. Our report shows that benign lesions may represent a possible cause of diagnostic errors. They must be excluded by histological analysis.