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Myofibroblastoma is a relatively rare, benign mesenchymal tumor that typically occurs in the breast parenchyma. Unlike mammary-type myofibroblastoma, myofibroblastoma that primarily arises in the lymph nodes exhibits nuclear palisading, and the term palisaded myofibroblastoma has been proposed, accordingly. We report 2 unusual cases of myofibroblastoma of the male breast, which showed a predominant (>90% of the entire tumor) nuclear palisading and Verocaylike bodies. The present cases represent a hitherto unreported variant of mammary-type myofibroblastoma closely mimicking schwannoma. The diagnosis of myofibroblastoma was supported by immunohistochemical analyses showing a diffuse staining for desmin and CD34. In addition, the diagnosis of myofibroblastoma was confirmed in 1 case cytogenetically by the demonstration of the monoallelic loss of the FOXO1/13q14 locus by fluorescence in situ hybridization. Pathologists should be aware of this unusual variant of mammary myofibroblastoma to assure a correct diagnosis. © 2013 Elsevier Inc. All rights reserved. [ABSTRACT FROM AUTHOR]

Ten cases of glioblastomas showing oncocytic changes are described. The tumors showed mononuclear to multinuclear cells and abundant, granular, eosinophilic cytoplasm. The cytoplasm of these same cells was filled by strongly immunoreactive mitochondria. At ultrastructure, numerous mitochondria, some of which were large, were evidenced in the cytoplasm of neoplastic cells. Finally, 9 of 10 of these cases had a significantly high mitochondrial DNA content compared with control tissue (P b .01). It seems that, for these tumors, the designation of oncocytic glioblastoma is appropriate. To the best of our knowledge, oncocytic changes have not been previously reported in such neoplasms. Oncocytic glioblastomas have to be added to the long list of various tumors that can manifest "unexpected" oncocytic changes in different organs. Albeit failing to show statistical significance (log- rank test, P = .597; Wilcoxon test, P = .233), we observed a trend for longer median survival in oncocytic glioblastomas, when compared with "ordinary" glioblastomas (median survival of 16 versus 8.7 months). Thus, it seems that the definition of neoplasms showing oncocytic changes, currently based on classic morphological parameters (ie, histology, ultrastructure, and immunohistochemistry), can be expanded by including the quantitative assessment of mitochondrial DNA content. © 2013 Elsevier Inc. All rights reserved. [ABSTRACT FROM AUTHOR]