AQP3 and hidradenoma: Among the benign skin tumors, positive AQP3 staining was seen in all 7 hidradenomas (all diffuse), 6/7 eccrine poromas (all diffuse), all 16 sebaceomas (4/16 focal, 4/16 intermediate, and 8/16 diffuse), and all 10 sebaceous adenomas (all diffuse).