[Metastatic skull tumors from cancers associated with subcutaneous mass lesions]

The incidence of metastatic brain tumors is increasing because of the recent progress in the detection and management of primary cancer. However, metastatic skull tumors from cancers associated with giant subcutaneous mass lesions are rare. We present four patients with metastatic skull tumors: two from hepatic cancer, one from lung cancer, and one from mamma cancer. In these patients, plain skull X-ray and bone CT showed osteolytic lesions. Angiograms revealed a tumor stain fed by abnormal vessels from the external carotid artery. MRI demonstrated masses with marked homogeneous enhancement with the "dural tail sign" in the dura adjacent to the tumors in three skull tumors from hepatic and mamma cancers, and a mass with slightly enhancement without the "dural tail sign" in a skull tumor from lung cancer. At surgery, hemorrhagic well-demarcated tumors were totally removed. The histological diagnosis was skull metastases from cancers in all cases. In cases with the "dural tail sign" on MRI, no tumor cells were seen in the inner layer of the dura and the dura adjacent to the tumors. It is possible that the "dural tail" is due to increased vascular permeability of the dural vessels. The recurrence of these skull tumors was not observed during the follow-up period. Surgical treatment for the metastatic skull tumors from cancers may be indicated to prevent deteriorating neurological symptoms affecting the quality of life.