Gliosarcoma Arising in Oligodendroglial Tumors (“Oligosarcoma”)

Abstract

Gliosarcomas are morphologically biphasic tumors composed of glial and sarcomatous elements. Only rare examples of gliosarcoma with oligodendroglial components have been reported. Seven patients with oligodendroglial tumors and a sarcomatous component were identified. Fluorescence in situ hybridization for 1p/19q was sought in glial and sarcomatous regions in all cases. Their mean age at diagnosis of gliosarcoma was 48 years (range 36 to 68) (F:M ratio=5:2). At first resection, the tumors included grade II oligodendroglioma (n=3), grade III oligodendroglioma (n=1), grade II oligoastrocytoma (n=1), and grade III oligoastrocytoma (n=2). The sarcomatous component developed in recurrent/progressive tumors in 6 cases but was a focal finding at first tumor resection in 1 and included fibrosarcoma (n=5), leiomyosarcoma (n=1), or pleomorphic myogenic sarcoma (n=1). Rhabdoid change was a focal finding in the sarcomatous component of 1 tumor. The glial component expressed both glial fibrillary acidic protein and S-100 in all cases, whereas the sarcomatous component at least focally showed smooth muscle actin (n=6), CD34 (n=4), S-100 protein (n=3), and epithelial membrane antigen (n=2) reactivity. Fluorescence in situ hybridization studies demonstrated 1p/19q codeletion in 5 cases, showed no evidence of deletion in 1 case, and technically failed in 1 case. Three of the 5 cases demonstrated 1p/19q codeletion in the sarcomatous component as well. Gliosarcomas with oligodendroglial elements are rare. The relatively frequent presence of 1p/19q codeletion in both glial and sarcomatous components supports the notion that the sarcomatous component represents a metaplastic change occurring in the glial element, the same mechanism active in classic astrocytic gliosarcomas.

High-grade glioma before and after treatment with radiation and Avastin: Initial observations

“…21 It is also expressed by tumor cells in some glioblastomas and gliosarcomas. [22][23][24] The upregulation of this marker in two of our cases may thus represent a transition to a "mesenchymal" phenotype. Alternatively, there may be a causal relationship between inhibition of VEGF and upregulation of smooth muscle actin: in vitro studies on human CD34-positive vascular progenitor cells demonstrated a differentiation into endothelial cells in response to VEGF, whereas addition of platelet-derived growth factor to the same progenitor cell type produces smooth muscle actin-positive cells with contractile properties.…”

Sarcoma-like tumor originating from oligodendroglioma

“…However, by following the intensive reexamination of the first radiological images and specimens, we could find no evidence that the sarcomatous components coexisted. [1]. Among these seven cases, four cases had received prior chemotherapy or radiotherapy; one case was not described, and two cases were purely observational.…”

“…In our case, the sarcomatous tumor arose 24 months after the first surgery and consisted of anaplastic features, as seen on histological examination. In the literature, cases of oligosarcoma have been reported [1,2,15]. Some of these occurred without preceding radiotherapy, although all had oligodendroglial components.…”

“…Most sarcomas of this nature have oligodendroglial components and were called ''oligosarcoma'' [1,2]. Sarcomas without oligodendroglial components occurring at sites of resected oligodendroglioma have not been reported.…”

Identification of t(1;19)(q12;p13) and ploidy changes in an ependymosarcoma: a cytogenetic evaluation

“…In most cases, the glial component is astrocytic [5]. However, there have been reports of the glial component being oligodendroglial [17] or ependymal [2,9,10,18,21]. The terms oligosarcoma and ependymosarcoma have been proposed for such composite tumors [17,18].…”