Contributed by Marian Christoph Neidert1, Henning Leske2, Katja Matoscevic1, Günter Eisele3, Elisabeth Rushing2, Oguzkan Sürücü1, *
1 Department of Neurosurgery, University Hospital Zurich, Switzerland
2 Department of Neuropathology, University Hospital Zurich, Switzerland
3 Department of Neurology, University Hospital Zurich, Switzerland
A 42-year-old male suffered a witnessed, new-onset generalized tonic-clonic seizure while driving a car, which lead to an accident. In addition to minor injuries, trauma work-up revealed a 3.6 x 2.6 x 3 cm dural-based mass compressing the right middle temporal gyrus. The lesion appeared well-circumscribed, oval in shape, showed moderate patchy contrast enhancement (Fig. 1). In addition, fine T2- and T1-hyperintense rimming was noted, accompanied by mild perifocal edema, and interestingly, homogenous hypointensity on T2-weighted images (Fig. 2). Evidence of calcification was absent on cranial computed tomography (not shown). Calcification was seen within a small (0.7x2.5x1 cm), fusiform lesion with homogenous contrast enhancement localized in the frontal falx, consistent with a meningioma (Fig. 3). The patient subsequently underwent right temporal osteoplastic craniotomy for the temporal lobe lesion. Intraoperatively, the lesion was adherent to the dura and resembled a meningioma with typical meningeal blood supply. After circular incision and coagulation of the dura, the tumor showed a glassy-whitish appearance. The rubber-like, cartilaginous consistency made it impossible to debulk the central components, despite highest volume of the ultrasonic surgical aspirator. Fortunately, the arachnoidal layer was intact throughout and adhesions were minimal. The core of the tumor could be partially resected using a regular scalpel and then the lesion was shelled-out en bloc (Fig. 4). Finally, the surgical result resembled a Simpson grade I resection of a meningioma.
Histopathological examination revealed a monomorphous proliferation of spindle-shaped cells with occasional whorls (Fig. 5a, 5b) and overall low cellular density. The tumor was reticulin positive (Fig. 6), but pseudoinclusions, calcification and mitotic figures were absent. On immunohistochemistry, scattered tumor cells were positive for anti desmin antibody (Fig. 7), but all were negative for S-100 (Fig. 8) and epithelial membrane antigen (EMA). Vessels showed immunoreactivity for CD34 (Fig. 9) and smooth muscle actin (SMA) (Fig 10), but the individual tumor cells were negative. What is your diagnosis?