We performed a systematic immunohistochemical study on 378 brain tumors using tissue microarray (TMA) technology. The aim of this study was to find new diagnostic biomarkers using antibodies established in our laboratory. Our TMA consisted of a grid of 1.5mm cores that were extracted from individual donor blocks. We carried out immunostaining with 37 antibodies. Staining for each antibody was scored using a threepoint system. We used hierarchical clustering analysis to interpret these data, which resulted in separation of all the brain tumors into seven groups. Although there were some exceptions, cases with the same histological diagnosis were generally grouped together. We then and GP1) showed significant differences between highgrade and lowgrade gliomas. Our new antibodies that are considered to have potential diagnostic utility are Olig2, PP5 and GP1. We conclude that TMA technology is highly useful in verifying the usefulness of newly established antibodies for brain tumor research.3

A 68-year-old man, who had no remarkable past medical history, was referred to a hospital because of disorientation and right-sided hemiparesis. On magnetic resonance imaging, a contrast-enhanced tumor in the left frontal lobe with perifocal edema was noted. He underwent left frontal lobectomy. Microscopic examination revealed infiltrative atypical astrocytes showing increased cellularity, distinct nuclear atypia, and many mitotic figures, while microvascular proliferation and necrosis were absent. Thus, the tumor was histologically diagnosed as anaplastic astrocytoma. It was of note that cytoplasmic eosinophilic granules were observed in approximately 25% of neoplastic cells. The granules were positively immunostained with anti-alphaB-crystallin antibody, and the other histochemical and immunohistochemical results also corresponded to Rosenthal fibers. The MIB-1 labeling index of the highest area of the tumor was 22%, while that of granular cells was 2.1%. An ultrastructural study revealed amorphous electron-dense structures attached to intermediate filament bundles, compatible with Rosenthal fibers. Such structures are relatively common in oligodendroglial tumors; however, they are extremely rare in astrocytic tumors. Fluorescence in situ hybridization targeted against chromosome 1 failed to demonstrate allelic loss of the short arm. The present case should also be discriminated from granular cell astrocytoma. We review related literature and discuss the significance of granules in gliomas.

Low grade diffuse gliomas arising in the brain are challenging to treat because of their ability to infiltrate adjacent tissue. We attempted to clarify the cellular composition and histopathological features of low grade gliomas by utilizing morphometric and immunohistochemical analyses. Seventy-eight cases of low grade gliomas were examined including 21 diffuse astrocytomas (DA), 36 oligodendrogliomas (OL), and 21 oligoastrocytomas (OA), based on the WHO classification system. Moreover, OL were subdivided into three types based on the morphological characteristics advocated by Daumas-Duport et al.: OL type I, OL type II, and OL type III. The cellularity, nuclear form factor, and conditional entropy corresponding to the nuclear pleomorphism were measured in each sample by the image analysis software "Gunmetry." Twenty-two cases were immunohistochemically analyzed for the expression of several antigens. Morphometric data indicated that the cellularity of OL type II was significantly higher than that of DA, and that the conditional entropy of OL type III was significantly lower than that of DA. Although the results of the immunohistochemical studies were almost consistent with previous reports, there were significant differences in the expression of GFAP, nestin and p53 between DA and OL. Double immunostaining revealed that expression of Olig2 and GFAP, and Olig2 and nestin was mutually exclusive in most glioma cells. Moreover, the coexpression of nestin and GFAP occurred in DA and OA, but not in OL. We conclude that each glioma include cells expressing GFAP, cells expressing nestin, and cells expressing Olig2 in a characteristic proportion for each tumor type. We suggest that diffuse gliomas share cellular compositions in different ratios and that they can be distinguished by morphometrical analysis.

A 31-year-old female complained of upper abdominal and back pain. Laboratory tests showed elevated levels of aspartate aminotransferase, alanine aminotransferase and α-fetoprotein. Computed tomography revealed that the tumor, measuring 14.5 cm × 10.4 cm, occupied the anterior and medial segments of the liver and consisted of multicystic and solid lesions. The preoperative diagnosis was a hepatic cystadenocarcinoma. The operation was performed urgently because of tumor rupture. Histopathologically, spindle and asteroid cells were found to have proliferated diffusely. There were no neoplastic epithelial tumor cells. Tumor cells had periodic acid-Schiff-positive hyalin globules. At the periphery, trapped normal bile duct cells were observed. The final diagnosis was embryonal sarcoma of the liver (ESL). Interestingly, irregular islands of chondrosarcoma-like lesions were found in the tumor and the tumor-associated vascular endothelium showed immunoreactivity for KIT. Two months after the operation, the tumor recurred. At 6 mo follow-up, the patient is alive with the disease and undergoing chemotherapy. This is the first report of ESL with chondroid differentiation.