Formalin Fixation as Tissue Preprocessing for Multimodal Optical Spectroscopy Using the Example of Human Brain Tumour Cross Sections

Figure 1

Histological features of brain tumour tissues used for spectroscopic analyses (H&E staining). (a) fibrous meningioma (WHO grade I sample (A)) with isomorphic tumour cells and eosinophilic collagen fascicles (arrow); (b) low-grade oligodendroglioma (WHO grade II, sample (B)) presented with the typical honeycomb pattern of tumour cells with isomorphic nuclei. Single cells resemble fried eggs with blue yolk (nucleus); neither mitosis nor vascular proliferations are detectable. (c) anaplastic ependymoma (WHO grade III, sample (C)) is a cellular neoplasm with prominent perivascular pseudorosettes (asterisks) and increased proliferation; (d) glioblastoma (WHO grade IV, sample (D)) is characterized by polymorphous tumour cells, some of which are multinucleate (asterisks), by mitotic activity and by prominent vascular proliferation. (e) plexus papilloma (WHO grade I sample (E)) presented with typical papillary architecture, isomorphous tumour cells, and nuclei; no mitoses are detectable; (f) low-grade oligodendroglioma (WHO grade II, sample (F)) with the characteristic honeycomb pattern (similar to Figure 1(b)); (g) features of anaplastic oligodendroglioma (WHO grade III, sample (G)) consists of a honeycomb pattern similar to low-grade oligodendroglioma, higher cellularity, and pleomorphic nuclei and occasional mitoses (arrow); (h) glioblastoma (WHO grade IV, sample (H)) as a highly cellular and polymorphous glial tumour with vascular proliferation (arrow) and multinucleated cells. Scale bar in (a) is valid for (a)–(h), 50 μm.