The clinical significance of "adenoid" formations of neoplastic astrocytes, imitating metastatic carcinoma, in gliosarcomas. A review of five cases.

Five cases of supratentorial gliosarcomas occurring in middle-aged and elderly patients are reported. In the gliomatous portions of the tumors there were areas with clusters and ribbons of cuboidal cells forming a cribriform pattern and structures resembling ducts and glands of a metastatic adenocarcinoma. Where the adenoid structures were embedded in a mucoid matrix, an imitation of mucus-producing ("colloid") carcinoma was created. In one patient who had a large pelvic mass (later identified as a benign leiomyoma) the histology of the brain tumor suggested a metastatic müllerian carcinosarcoma. The pseudoglandular elements in each case could be identified as being composed of primitive astrocytes, partly by finding transitions to more mature and typical astrocytes and partly by positive staining with the immunoperoxidase method for glial fibrillary acidic protein (GFAP). The recognition of this morphologic variant of malignant glial tumors is important, particularly in patients of the age group in which primary carcinomas elsewhere in the body occur with increasing frequency. In such patients the correct diagnosis of their brain tumor can avoid the added post-craniotomy discomfort and expense of a "workup for a primary tumor."