This subtype also requires extensive differential diagnosis with one other subtype of urothelial malignancy—clear-cell adenocarcinoma of the urinary tract, which is a special type of Müllerian malignancy (PAX 8-positive, negative for GATA3, p63, ER, PR, and WT1), as well as clear-cell–renal-cell carcinoma (RCC-, PAX8- and CD10-positive) [12,13,14,15,16,17]. The gene discussed is GATA3; the disease is clear cell adenocarcinoma.