The cyst lining was positive for epithelial markers (pancytokeratin [Figure 3C], AE1-AE3, and CK7), but negative for melanocytic (HMB-45 [Figure 2A] and Melan-A), muscular (smooth muscle actin [Figure 2B] and desmin), and hormonal (ER [Figure 2C] and PR [Figure 2D]) markers. The gene discussed is PMEL; the disease is cyst.