The adjacent temporal rim-enhancing tumor (Fig. 2b, Temporal mass, see also Fig. 1b) had a striking epithelioid morphology, with large epithelioid cells containing nuclei with prominent nucleoli, absence of GFAP labeling, focal plasma membrane NHERF1 labeling, as in papillary lung adenocarcinoma [9], and very focal low molecular weight cytokeratin CAM5.2 and Olig2 expression. The gene discussed is OLIG2; the disease is papillary lung adenocarcinoma.