Noninvasive urothelial carcinoma (UC) with glandular differentiation in the absence of infiltrating carcinoma is a rare entity that has not been well characterized. We retrieved 24 cases of noninvasive UC of the bladder with glandular differentiation on biopsy (n=20) or transurethral resection (n=4) without an associated invasive component. The cases were identified from the consult files of one of the authors between 1992 and 2008. Mean patient age at diagnosis was 70 years (range: 48 to 87 y) and 75% were male. Half of the cases were pure noninvasive UC with glandular differentiation; half were associated with either carcinoma in situ or high-grade noninvasive papillary carcinoma. The glandular component consisted of 1 or more patterns: papillary (46% of cases), glandular (42%), cribriform (33%), and flat (25%). Mitoses, apoptosis, and necrosis were identified in 83%, 67%, and 17% of the biopsies, respectively. One case was a recent diagnosis, and 5 patients either refused treatment or were lost to follow-up. Of the 18 patients with available follow-up information, 9 (50%) did not develop invasive carcinoma; the remaining 9 (50%) eventually developed an invasive bladder tumor. Of these, 2 were small cell carcinoma, 3 were poorly-differentiated UC (2 of these developed widespread metastases), and 4 were UC, not otherwise specified. In both instances of eventual small cell carcinoma, and in 2 of the 3 cases of poorly-differentiated UC, the initial biopsy consisted of pure noninvasive UC with glandular differentiation without carcinoma in situ or noninvasive papillary carcinoma. Of note, none of the patients in the study developed invasive adenocarcinoma.