Fig. 1

Magnetic resonance imaging, intraoperative histological and cytological findings of the dura-attached supratentorial extra-axial tumor. a–c Magnetic resonance imaging findings at admission. An axial T1-weighted image showing a cystic mass on left parietal to temporal lobe with hypo- to iso-intensity (a). An axial T2-weighted image (b) and gadolinium-enhanced T1-weighted image (c) showing a heterogeneously hyperintense mass with perifocal edema at the periphery (arrowhead in b) and sanguineous material in the cystic spaces. Hyperintense peritumoral band (b) and dural tail sign (c) are indicated by arrows, suggesting a dura-based extra-axial lesion. d–f, Intraoperative histological images showing sheet-like proliferation of tumor cells with branching capillary blood vessels (d), no apparent fine fibrillary processes in the perivascular anucleate zone (e a higher magnification of the blood vessel labeled with an asterisk in d), and rhabdoid cytoplasm in tumor cells (f). g, h, Low-magnification (g) and high-magnification (h) images of an intraoperative cytological specimen. Tumor cells proliferated in irregular clusters close to or distant from blood vessels (g squashed specimen). The tumor cells have hyperchromatic nuclei and eosinophilic cytoplasm with fibrillary processes (h imprinted specimen). Mitosis is also seen (inset in h, squashed specimen). Intraoperative specimens were stained using HE (d–h). Bars: 2 cm in a–c, 100 µm in d, 25 µm in e–h, 50 µm in g, and 12.5 µm in the inset in h