Post-radiation fibrosarcoma of the cerebrum associated with a prominent, lace-like, perivascular, desmoplastic change.

An intra-axial tumor measuring about 4 cm was excised from the right temporal lobe of a 35-year-old woman, who had a past history of resection of craniopharyngioma and postoperative radiation 21 years earlier. The tumor involved both the cortex and white matter, but was not attached to the dura mater. It consisted of a dense, interlacing, fascicular proliferation of atypical fibroblastic cells and was associated with an extensive, lace-like, desmoplastic change mainly involving the perivascular region around the tumor and overlying the subarachnoid space. The histopathological features of the desmoplastic change resembled meningioangiomatosis, but no proliferation of meningothelial cells was noted. The patient has been free from recurrence for 12 months since the operation. The association of primary cerebral fibrosarcoma with an extensive, lace-like, perivascular, desmoplastic change has not been documented in the literature. The radiation administered 21 years previously may have played some pathogenetic role in the perivascular desmoplastic change, and a malignant transformation of fibroblasts within the perivascular collagenous tissue is considered the most likely origin of the fibrosarcoma.