90 percent of lesions are TCC, 5-9 percent of lesions squamous cell and 1-2 percent of lesions adenocarcinoma.
Urothelial carcinoma is the most common malignancy of the urinary tract and is the second most common cause of death among genitourinary tumors.
At initial presentation, 80% of urothelial tumors are non–muscle invasive
There are multiple growth patterns of urothelial cancer, including flat carcinoma in situ (CIS), papillary tumors that can be low or high grade, and sessile tumors with a solid growth pattern.
Non–muscle-invasive cancers can be very large because of lack of genetic alterations required for invasion.
Invasive tumors can be quite small if early genetic changes occur within the tumor cell, allowing for an invasive phenotype.
Primary TCC with metaplastic elements is not uncommon.
Cytologic grade adds some independent prognostic information by interpretation on a 1-3 scale is less uniform.
Tumor stage is the predominant factor in prognostic outcome.
Epithelial dysplasia. Dysplasia exhibits irregular urothelial and nuclear changes in a gradation toward carcinoma. High-grade dysplasia is difficult to distinguish from CIS.
This is distinct from atypia, which is defined as an increase in cell layer number without changes in tissue structure or nuclear appearance.
Carcinoma in situ. Urothelial dysplasia has abnormal cytologic and nuclear changes that are preneoplastic but are not sufficient to be characterized as CIS.
Similar to high grade dysplasia, yet lacks polarity and cell adhesion.
Probable progenitor of muscle invasive disease.
Superficial disease Papillary or nodular lesions confined to the mucosa [Ta] constitute true superficial disease.
Lesions invading the lamina propria [T1] have a significantly higher chance of recurrence and progression [30-40 percent]. They require aggressive treatment and close observation.
Muscle invasive disease
True involvement of the detrusor which can appear nodular or tentacular. Generally all of high cytologic grade.
Squamous cell. Secondary to chronic irritation. Stone disease and chronic cathers as well as schistosomiasis infection.
Adenocarcinoma. Rare lesions. Likely urarchal origin when at bladder dome. Must rule out metastatic deposit from another primary site such as breast or colon.
Sarcoma. Rare in adults. Embryonal rhabdomyosarcoma seen in infants and young children.
Small cell carcinoma. Rare lesions with neuroendocrine features. Generally very aggressive clinical course.
Epstein JI, Amin MB, Reuter VR, Mostofi FK: The World Health Organization/International Society of Urological Pathology consensus classification of urothelial (transitional cell) neoplasms of the urinary bladder. Bladder Consensus Conference Committee. Am J Surg Pathol 1998; 22(12):1435-1448.
Montironi R, Lopez-Beltran A: The 2004 WHO classification of bladder tumors: a summary and commentary. Int J Surg Pathol 2005; 13(2):143-153.
Sauter G, Algaba F, Amin A, et al: Nonivasive urothelial neoplasias: WHO classification of noninvasive papillary urothelial tumors. In: Eble J, Sauter G, Epstein JI, Sesterhenn I, ed. World Health Organization classification of tumors, Lyon (France): IARC Press; 2004.