Posterior fossa involvement in a recurrent gliosarcoma

Abstract

Gliosarcoma (GSM) is a WHO grade 4 tumor and a variant of glioblastoma multiforme with predilection for the temporal lobe. We record, perhaps the first case in literature, of a temporal lobe GSM with recurrence involving the posterior fossa. A 50-year-old man presented to us with headache, vomiting, and lethargy of relatively recent onset. Magnetic resonance imaging revealed a well-circumscribed lesion in the left temporal lobe for which left temporal craniotomy with radical excision of the tumor was performed. Histopathology was suggestive of GSM. He presented to us within a month of the first surgery with a large recurrence involving the temporal lobe. He underwent a second surgery with radical excision of the tumor. Histopathology was confirmatory of GSM. He was administered concomitant chemotherapy and radiotherapy. Within a fortnight of starting adjuvant therapy, the bone flap started bulging and a repeat computed tomography scan revealed a large recurrence extending into the posterior fossa. The patient's relatives refused consent for third surgery and he finally succumbed on postoperative day 21. GSMs are aggressive tumors that have a temporal lobe predilection, but they may present anywhere in the brain. Detailed studies on larger cohort of cases are needed to understand the true nature of these biphasic tumors.

Keywords: Gliosarcoma; posterior fossa tumor; recurrence in posterior fossa.

Figure 1

Postcontrast axial MRI showing a large intra-axial space occupying lesion in the left temporal lobe with peripheral enhancement and peritumoral edema

Figure 2

Postcontrast axial CT scan showing a large recurrent tumor almost occupying the whole posterior part of the left temporal lobe

Figure 3

Postoperative contrast axial CT showing radical excision of tumor with enhancement along the tentorial leaflet

Figure 4

Photomicrographs show a high-grade tumor composed of polygonal tumor cells (b and c) admixed with spindle cells (a and d). Nuclear pleomorphism and mitoses seen. (H and E, a and b: ×100; c and d: ×200)

Figure 5

(a) Photomicrograph shows increase in intratumoral reticulin (reticulin stain, ×100); (b) IHC; GFAP ×100); (c) (IHC; p53 ×100); and (d) IHC; MIB-1 ×200): Photomicrographs of the immunohistochemistry, which is focal positive for glial fibrillary acidic protein (b), which is retic poor areas and suggest glial area and the tumor is diffusely positive for p53 protein (c). MIB-1 labeling index (d) is approximately 8%–10%

Figure 6

Postcontrast axial CT scan showing recurrent tumor in the left posterior temporal lobe extending into the posterior fossa and compressing the brain stem