A 78-year-old woman underwent radical cystectomy due to high-grade infiltrating urothelial carcinoma of the urinary bladder. Histopathological examination of the bladder neck revealed coincidental urothelial carcinoma and tubular neoplasm resembling prostatic acinar adenocarcinoma. The latter was accompanied by a non-invasive component showing features of high-grade prostatic intraepithelial neoplasia (PIN). The lesion showed immunopositivity for prostate-specific antigen, prostein, and androgen receptor. The diagnosis of Skene’s gland adenocarcinoma (SGA) was established. This is the 14th case of SGA in the literature, and the first coexisting with urothelial carcinoma. Our case demonstrates a possible origin of SGA from precursors resembling PIN.