Fig. 3

Examples of EIF1AX mutation in a primary leptomeningeal melanocytoma and intermediate-grade melanocytic tumor. a. H&E staining of the melanocytoma of patient #2, consisting of epithelioid cells with moderate to strong melanin pigmentation. b. BAP1 immunostaining of the melanocytoma depicted in A revealing positive staining of nuclei in more than 90 % of tumor cells. The arrows indicate nuclear staining in endothelial cells. Note that cytoplasmic staining is also present. c. H&E staining of the intermediate-grade melanocytic tumor of patient #19 showing a nested proliferation of epithelioid cells; the arrow indicates a mitotic figure. d. BAP1 immunostaining of the intermediate-grade melanocytic tumor depicted in C revealing positive staining of nuclei in more than 90 % of tumor cells. e. Forward sequence tracing surrounding codon 3 of EIF1AX showing a c.9G > C (p.(Lys3Asn)) mutation in the melanocytoma depicted in (a) and (b). f. Forward sequence tracing surrounding codon 10 of EIF1AX showing a c.28A > G (p.(Lys10Glu)) mutation in the intermediate-grade melanocytic tumor depicted in (c) and (d)