Oncocytic glioblastoma: a glioblastoma showing oncocytic changes and increased mitochondrial DNA copy number

Oncocytic glioblastoma: a glioblastoma showing oncocytic changes and increased mitochondrial DNA copy number

Human Pathology, May 2013

23664543

Gianluca Marucci, Alessandra Maresca, Leonardo Caporali, Anna Farnedi, Christine Margaret Betts, Luca Morandi, Dario de Biase, Serenella Cerasoli, Maria Pia Foschini, Elena Bonora, Michele Vidone, Giovanni Romeo, Elena Perli, Carla Giordano, Giulia d'Amati, Giuseppe Gasparre, Agostino Baruzzi, Valerio Carelli, Vincenzo Eusebi

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 < .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.