A Case of Cerebral Metastasis from Malignant Fibrous Histiocytoma

ABSTRACT

This is a rare case of cerebral metastasis from malignant fibrous histiocytoma(MFH) of the soft tissue. A 62-year-old man underwent craniotomy for resection of multiple intracerebral masses under the impression of metastatic brain tumor with unknown primary site. Preoperative investigation failed to detect any extracranial lesion. At six months after the operation and whole brain radiotherapy, right shoulder mass was detected to grow and excised. Specimen from the brain and shoulder lesions revealed identical pathological findings of malignant fibrous histiocytoma except existence of glial fibrillary acidic protein(GFAP)-positive cells only in brain lesions. Palliative radiotherapy was performed for subsequently developing metastatic lesions in skeletal system. At twelve months after initial diagnosis recurrent lesion at right shoulder was detected and chemotherapy is given. This case is unique because metastatic brain lesion from MFH is rare and also cerebral metastasis as an initial manifestaion of MFH has not been reported before. Another important finding is that there was expression of GFAP only in brain lesions but not in extracranial primary site lesion. Although the presence of GFAP-positive cells is thought as one of characteristic histological findings of primary intracrainal MFH, our observation supports the hypothesis that GFAP-positive cells in primary intracranial MFH may be nonneoplastic astrocytes secondarily involved by MFH.