PMC5843975_01
Pre-operative MRI (a, b) T1-weighted post gadolinium images show an avidly enhancing mass with well-defined, lobulated borders in the left frontoparietal region. Preoperative transcranial magnetic stimulation (c) and intraoperative motor mapping and monitoring (d) demonstrate that the primary motor cortex was located in front of the tumor, confirming the location of the tumor within the central sulcus. Post-operative MRI axial T1-weighted pre gadolinium (e) and post gadolinium (f) show a small volume of hemorrhage in the surgical bed but no residual tumor
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F1
An MRI of the brain demonstrated an avidly enhancing lesion centered in the left perirolandic region (involving precentral and postcentral gyri) measuring 38 x 43 x 39 mm [Figure 1a and b] Multiple serpiginous signal voids were observed in the lesion, but no definite dural involvement, raising the suspicion of an intra-axial tumor. Both methods demonstrated that the primary motor cortex was located in front of the tumor, therefore confirming the location of the tumor within the central sulcus [Figure 1c and d]. Gross total resection of the tumor was achieved with preservation of the motor mapping throughout the procedure [Figure 1e and f].
Toluidine blue stained smear preparation (a) shows spindle shaped, monomorphic neoplastic cells with prominent nucleoli in a loose matrix and mast cells. Epithelioid and spindle-shaped cells arranged in mucoid/myxoid background with hyalinised elements (b, c). The cytoplasm is frequently vacuolated and a mitotic figure is noted (c). Eosinophilic cytoplasmic inclusions in keeping with rhabdoid cells (d). Strong, diffuse immunoreactivity with CD34 (e). Loss of expression in the tumor cells by INI1, while the nuclear staining is preserved in the endothelial cells (f)
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F2
The toluidine blue stained intraoperative smear preparation confirmed neoplastic tissue with a loose matrix and monomorphic tumor cells together with associated mast cells but no definite diagnosis could be given [Figure 2a]. Histology showed a tumor composed of cells both epithelioid and spindle-shaped with oval, relatively monotonous, sometimes eccentric, nuclei and prominent nucleoli [Figure 2b-c]. The cytoplasm was frequently vacuolated and also there were many eosinophilic cytoplasmic inclusions in keeping with rhabdoid cells [Figure 2d]. Immunohistochemistry showed strong, diffuse positivity with vimentin, synaptophysin, CD34 [Figure 2e], calretinin and in almost all cells with smooth muscle actin (SMA). The INI1 (BAF47) was negative in the tumor cells [Figure 2f].