Main histological types of BCa, incidence, characteristics
| Histological type | Incidence | Characteristics |
|---|---|---|
| Urothelial cancer | 90% | The most common type, develops from the transitional epithelial cells lining the urinary bladder. It comes in non-invasive (NMIBCa) and invasive (MIBCa) forms. It is the predominant type in developed countries. |
| Squamous cell carcinoma | 3–5% | Associated with chronic inflammation, most often caused by schistosome infection (especially in endemic regions) or chronic cystitis. It is characterized by an aggressive course. |
| Adenocarcinoma | < 2% | It arises from glandular cells; it may occur primarily in the bladder or be secondary (metastatic) from other locations. It is often associated with congenital defects such as persistent urachus. |
| Small cell carcinoma | < 1% | A very rare, highly aggressive type of cancer with a rapid progression, often with metastases at diagnosis. Histologically similar to small cell lung cancer. |
| Sarcoma | < 1% | Rare; originates from muscle tissue or other mesenchymal structures of the bladder. More common in children and young adults, known as rhabdomyosarcoma. |
| Mixed cancer | Variable | May contain features of different types, e.g., urothelial and squamous. Mixed cancer shows a more aggressive course compared to pure urothelial tumors. |
BCa: bladder cancer; MIBCa: muscle-invasive BCa; NMIBCa: non-muscle invasive BCa