Unusual malignant glioma with extensive fibrosis in an adult

Abstract

Collagen production is seen in gliosarcomas, desmoplastic infantile astrocytomas and gangliogliomas, and gliomas that are infarcted or treated with radiotherapy. The term “gliofibroma” has been suggested for very rare astrocytomas with extensive collagen production (Acta Neuropathol 1993;85:349; JNEN 1978;38:300‐313) by the glial cells. An unusual malignant glioma with extensive desmoplasia arose in a 63 year old male with a 3 month history of seizures. Imaging studies showed a focally enhancing lesion in the right motor cortex. MR spectroscopy demonstrated an increased choline/creatine ratio and decreased NAA metabolite. A well‐defined neoplasm 3 millimeters below the pial surface had a matrix rich in collagen and reticulin, and several patterns. Less cellular, more fibrotic regions contained anaplastic polygonal to spindly cells . More cellular regions had sheets of pleomorphic oval cells with apoptotic bodies and frequent mitoses. Rounded nodules of clear, uniform tumor cells were present. Tumor cells expressed S100, vimentin and GFAP but were negative for epithelial, mesenchymal and neuronal markers. There was no necrosis, nor endothelial proliferation, but MIB‐1 proliferation index was approximately 30%. The term “malignant gliofibroma” may be useful for rare tumors of glial origin, which have produced a collagen‐ and reticulin‐rich matrix without treatment, infarct or associated sarcoma.