Fig. 3

Tumor histology for patients 1, 3 and 16 who had adverse outcomes. Tumor 1 (A–D) exhibits Spitz architecture (A, HES ×10) and fusiform Spitz cytology (B, HES ×200), with p16-positivity (C, p16 IHC ×100) and no 9p21 deletion (D, FISH ×600). Tumor 3 (E–H) was a compound Spitz tumor (E, HES ×10) with epithelioid Spitz cytology (F, HES ×200), loss of p16 (G, p16 IHC ×100) and heterozygous 9p21 deletion (H, FISH ×600). Tumor 16 (I–L) was a densely cellular melanocytic dermal tumor (I, HES ×10) with nevoid cytology (J, HES ×200), p16-negativity (K, p16 IHC ×100) and homozygous 9p21 deletion (L, FISH ×600). For more detailed descriptions, see Table 3.