Rapid expansion of benign scalp neurofibroma caused by massive intratumoral hemorrhage--case report.

A 62-year-old man with neurofibromatosis type 1 presented with rapid growth of a scalp mass. Head computed tomography demonstrated a large extracranial tumor of soft tissue density with massive intratumoral hematoma. Cerebral angiography demonstrated remarkable hypervascularity of the tumor. Preoperative embolization and total removal of the tumor was performed. The tumor contained a large amount of intratumoral hematoma (500 ml). The histological diagnosis was neurofibroma without malignant transformation. Benign scalp neurofibroma showing massive intratumoral hemorrhage is rare. Rapid growth or intratumoral hemorrhage in neurofibroma may be an indicator of malignant transformation.