Bladder cancer is of the following types -

(A) UROTHELIAL CARCINOMA:-

The most prevalent type of bladder cancer is urothelial carcinoma, commonly known as transitional cell carcinoma (TCC). Urothelial carcinoma is nearly always the cause of bladder cancer. These tumors begin in the urothelial cells that line the inside of the bladder.

Urothelial carcinoma (UCC) accounts for around 90% of all bladder malignancies. It also accounts for 10% to 15% of all kidney malignancies detected in adulthood.

Urothelial cells also line other parts of the urinary tract, including the renal pelvis (the region of the kidney that attaches to the ureter), the ureters, and the urethra. Malignancies in these areas are occasionally seen in people with bladder cancer, thus the entire urinary tract must be examined for tumors.

Other types of bladder cancer:-

Other cancers can begin in the bladder, although these are far less frequent than urothelial (transitional cell) cancer.

(A) SQUAMOUS CELL CARCINOMA:-

Squamous cell carcinoma is the second most prevalent type of bladder cancer.

It makes for around 4% of all bladder malignancies. Squamous cell carcinoma is associated with persistent bladder irritation, such as infection or long-term usage of a urinary catheter.

Squamous cells resemble the flat cells on the skin's surface. Almost all squamous cell carcinomas of the bladder are invasive. Squamous cell carcinoma is most common in regions where schistosomiasis, a parasitic infection, is prevalent, such as in the Middle East.

(B) ADENOCARCINOMA:-

It is a rare form of bladder cancer that accounts for about 1-2 percent of cases.

Adenocarcinoma develops in the cells that make up the bladder's mucus-secreting glands. These cancer cells have a lot in common with gland-forming cells of colon cancers. It is associated with congenital abnormalities in the bladder, as well as persistent infection and inflammation. Almost all adenocarcinomas of the bladder are invasive.

(C) SMALL CELL CARCINOMA:-

It is a rare type of bladder cancer, accounting for less than 1% of all bladder malignancies diagnosed. This aggressive sort of cancer develops in neuroendocrine cells, which are small nerve-like cells found in the bladder. It is usually diagnosed at a later stage after it has spread to other regions of the body. It is often treated with a combination of treatments including chemotherapy, surgery, and radiation therapy.

(D) SARCOMA:-

It is yet another rare kind of bladder cancer that starts in the muscular layer of the bladder wall. Sarcomas can occur in both children and adults. It accounts for around 1% of all adult malignancies. But, sarcomas represent about 15% of all childhood cancers.

(a) Soft Tissue Sarcoma-

Soft-tissue sarcomas (STS) are tumors that start in the connective tissues that support and link the body, such as muscles, nerves, tendons, blood vessels, fat cells, lymph vessels, and joint lining. As a result, STS can manifest itself nearly everywhere in the body. When an STS is small, it may go unnoticed since it does not generally cause problems, such as pain. However, when an STS progresses, it can cause discomfort and disrupt the body's normal functions.

(b) Rhabdomyosarcoma-

It is a type of soft tissue sarcoma that starts in immature mesenchymal cells that eventually develop into muscle. It grows in a striated muscle.

It can develop anywhere in the body, including the urinary and reproductive organs in around 30% of cases.

INVASIVE and NON-INVASIVE BLADDER CANCER

(a) Invasive bladder cancer-

These cancers are present only in the inner layer of cells (the transitional epithelium). They have not grown into the deeper layers of the bladder wall.

(b) Non-invasive bladder cancer-

These cancers have developed into deeper layers of the bladder wall. Invasive cancers are more likely to spread and are more difficult to cure.

Bladder cancer can also be characterized as superficial or non-muscle invasive.

(c) Non-muscle invasive cancer-

This bladder cancer typically has only developed into the lamina propria and not in the muscle. It includes both invasive and non-invasive tumors.

PAPILLARY and FLAT CARCINOMAS:-

Based on how bladder cancer grows, these are also divided into two subtypes, papillary and flat.

(A) Papillary carcinoma-

Papillary carcinomas form thin, finger-like extensions from the bladder's inner surface toward the hollow core. Papillary tumors frequently develop toward the bladder's center, rather than into the deeper layers. These tumors are known as non-invasive papillary cancers. Very low-grade (slow-growing), non-invasive papillary cancer, also known as a papillary urothelial neoplasm of low malignant potential (PUNLMP), has a very excellent prognosis.

(B) Flat carcinoma-

It does not develop toward the hollow part of the bladder at all. If a flat tumor is present only in the inner layer of bladder cells, it is called a non-invasive flat carcinoma or a flat carcinoma in situ (CIS).

An invasive urothelial (or transitional cell) carcinoma develops when a papillary or flat tumor spreads into deeper layers of the bladder.