A 49-year-old male who is a long-term smoker presents with frequency and hematuria. Histologic examination of sections taken from an exophytic lesion of the urinary bladder reveal groups of atypical cells with frequent mitoses forming finger-like projections that have thin, fibrovascular cores. These groups of atypical cells do not extend into the lamina propria and muscularis. No glands or keratin production are found. What is the most accurate diagnosis for this bladder tumor?
Neoplastic lesions of the urinary bladder may either be benign or malignant. There is some controversy involving some types of benign lesions of the bladder. In paicular, there is disagreement as to whether papillary lesions may be benign (papillomas). Many pathologists would classify papillary transitional lesions that lack cellular atypia or numerous mitoses as grade I (low-grade) papillary transitional cell carcinomas (TCCs) and not papillomas. Pathologists do agree, however, on the existence of a rare type of benign lesion called an inveed papilloma, which is characterized by nodular mucosal lesions that histologically have an endophytic growth pattern. Malignant neoplasms of the bladder may be transitional cell carcinomas, which are by far the most common type of tumor of the urinary bladder; squamous cell carcinomas, which produce keratin; or adenocarcinomas, which form glandular structures. TCCs may be either papillary or flat lesions. Papillary TCCs, which are the most common type of bladder cancer, may be either invasive or noninvasive. Noninvasive papillary TCCs are not referred to as being in situ, as that term implies a noninvasive, nonpapillary lesion. Nonpapillary (flat) TCCs may also be invasive (into the lamina propria or muscularis) or noninvasive (in situ). In contrast, squamous cell carcinomas of the urinary bladder are quite rare except in Egypt and other areas of the Middle East, where they are associated with schistosomiasis. Similarly, adenocarcinomas of the urinary bladder are quite rare, except that they may be associated with urachal epithelial remnants located in the dome of the bladder, glandular metaplasia, or cystitis glandularis. Reference: Robbins & Cotran Pathologic Basis of Disease, 9edition
Adenocarcinoma, noninvasive
Inveed papilloma
Transitional cell carcinoma in situ
Papillary transitional cell carcinoma (TCC), noninvasive
miscellaneous