Tobacco smoking is associated with an increased risk of ureteral cancer.

Cystitis glandularis is a term describing a metaplasial transformation of mucosal cells lining the urinary bladder. The main importance is in histopathology, distinguishing the metaplastic change from urothelial cell carcinoma. It is a very common finding in bladder biopsies and cystectomies, and most often found in the trigone area. Cystitis glandularis lesions are usually present as small microscopic foci; however, occasionally it can form raised intramucosal or polypoid lesions. The cystitis glandularis lesions are within the submucosa.

An inverted papilloma is a type of tumor in which surface epithelial cells grow downward into the underlying supportive tissue. It may occur in the nose and/or sinuses or in the urinary tract (bladder, renal pelvis, ureter, urethra). When it occurs in the nose or sinuses, it may cause symptoms similar to those caused by sinusitis, such as nasal congestion. When it occurs in the urinary tract, it may cause blood in the urine.

Urothelial carcinoma is a prototypical example of a malignancy arising from environmental carcinogenic influences. By far the most important cause is cigarette smoking, which contributes to approximately one-half of the disease burden. Chemical exposure, such as those sustained by workers in the petroleum industry, the manufacture of paints and pigments (e.g., aniline dyes), and agrochemicals are known to predispose one to urothelial cancer. Interestingly, risk is lowered by increased liquid consumption, presumably as a consequence of increased urine production and thus less "dwell time" on the urothelial surface. Conversely, risk is increased among long-haul truck drivers and others in whom long urine dwell-times are encountered. As with most epithelial cancers, physical irritation has been associated with increased risk of malignant transformation of the urothelium. Thus, urothelial carcinomas are more common in the context of chronic urinary stone disease, chronic catheterization (as in patients with paraplegia or multiple sclerosis), and chronic infections. Some particular examples are listed below:

1. Certain drugs, such as cyclophosphamide, via the metabolites acrolein and phenacetin, are known to predispose to TCC (the latter especially with respect to the upper urinary tract).

2. Radiation exposure

3. Somatic mutation, such as deletion of chromosome 9q, 9p, 11p, 17p, 13q, 14q and overexpression of RAS (oncogene) and epidermal growth factor receptor (EGFR).

The median overall survival rate is about 50% in 5 years. Worse prognostic factors include the presence of residual tumor at the margin of the resection specimen (R+), invasion of the peritoneum and metastatic disease.

Immunoperoxidase stains have identified antigens of the human papillomavirus (HPV) types 6 and 11 in approximately 50% of cases of squamous cell papilloma.

There are two main types of cystitis glandularis, non-mucinous and mucinous (intestinal). The difference is in the cellular production of mucin, a normal feature of colonic and intestinal epithelial cells but not of urothelial cells. Another distinction is made between focal areas and diffuse involvement of the bladder. Whereas focal areas are more common, diffuse involvement is seen in chronically irritated bladders, such as in paraplegics or those with bladder stones or indwelling catheters. Individuals with diffuse intestinal-type cystitis glandularis are at increased risk for developing bladder cancer.

Between 1988 and 2001 in the United States, cancer surveillance reports to SEER included 1,333 cases of ureteral cancer in adults: 808 male and 525 female, 1,158 white and 42 black. Of the total, 1,251 (94%) were transitional cell carcinoma of the papillary type. "Five-year relative survival rates from cancers of the ureter were similar among males vs. females..."

Inverted papillomas are definitively diagnosed by histologic examination. However, Magnetic Resonanace Imaging (MRI) may show a characteristic feature described as a Convoluted Cerebriform Pattern (CCP). A retrospective study published in the American Journal of Neuroradiology concluded that identification of CCP by MRI in a patient with a nasal tumor made the diagnosis of Inverted papilloma quite likely. The study reported the sensitivity and specificity to be 100% and 87% respectively. CCP can be associated with other malignant tumors as well.

A papilloma (plural papillomas or papillomata) ("" + "") is a benign epithelial tumor growing exophytically (outwardly projecting) in nipple-like and often finger-like fronds. In this context refers to the projection created by the tumor, not a tumor on an already existing papilla (such as the nipple).

When used without context, it frequently refers to infections (squamous cell papilloma) caused by human papillomavirus (HPV), such as warts. Human papillomavirus infection is a major cause of cervical cancer, although most HPV infections do not cause cancer. There are, however, a number of other conditions that cause papilloma, as well as many cases in which there is no known cause.

Treatment may include the following:

- Surgery with or without radiation

- Radiotherapy

Fast neutron therapy has been used successfully to treat salivary gland tumors, and has shown to be significantly more effective than photons in studies treating unresectable salivary gland tumors.

- Chemotherapy

Normally found in children or young adults, a common cause of conjunctival squamous cell papilloma is during childbirth, when the mother passes the virus to her child.

Little is known about the total incidence of salivary gland tumours as most benign tumours go unrecorded in national cancer registries. The majority of salivary tumours are benign (65-70%). Within the parotid gland 75 - 80% of tumours are benign. Around 50% of the tumours found in the submandibular glands are benign. Sublingual gland tumours are very rare but if present, they are most likely to be malignant.

In the United States, salivary gland cancers are uncommon with an incidence rate of 1.7 in 100000 between 2009 and 2013.

Choroid plexus papillomas are benign tumors that are usually cured by surgery; malignant progression has been rarely reported.

A squamous cell papilloma is a generally benign papilloma that arises from the stratified squamous epithelium of the skin, lip, oral cavity, tongue, pharynx, larynx, esophagus, cervix, vagina or anal canal. Squamous cell papillomas are a result of infection with human papillomavirus (HPV).

It has been estimated that VUR is present in more than 10% of the population. Younger children are more prone to VUR because of the relative shortness of the submucosal ureters. This susceptibility decreases with age as the length of the ureters increases as the children grow. In children under the age of 1 year with a urinary tract infection, 70% will have VUR. This number decreases to 15% by the age of 12. Although VUR is more common in males antenatally, in later life there is a definite female preponderance with 85% of cases being female.

Transitional cell carcinoma (TCC) also urothelial carcinoma (UCC), is a type of cancer that typically occurs in the urinary system. It is the most common type of bladder cancer and cancer of the ureter, urethra, and urachus. It is the second most common type of kidney cancer, but accounts for only five to 10 percent of all primary renal malignant tumors.

TCC arises from the transitional epithelium, a tissue lining the inner surface of these hollow organs.

When the term "urothelial" is used, it specifically refers to a carcinoma of the urothelium, meaning a TCC of the urinary system.

Urachal cancer is a very rare type of cancer arising from the urachus or its remnants. The disease might arise from metaplasic glandular epithelium or embryonic epithelial remnants originating from the cloaca region.

It occurs in roughly about one person per 1 million people per year varying on the geographical region. Men are affected slightly more often than women mostly in the 5th decade of life but the disease can occur in also in other age groups.

It can involve the urinary bladder, but is not bladder cancer in the usual sense. Urachal cancer can occur at any site along the urachal tract.

Urachal cancer was mentioned by Hue and Jacquin in 1863 followed by an elaborate work by T. Cullen in 1916 about diseases of the umbilicus, while C. Begg further characterized urachal cancer in the 1930s. Detailed diagnostic and staging schemes were proposed by Sheldon et al in 1984, which remain widely used today.

Definitive causes of ureterocele have not been found. While the abnormal growth occurs within the uterus, it has not been substantiated that genetics are to blame.

Internationally tumors of the choroid plexus are rare, accounting for 0.4-0.6% of all intracranial neoplasms. It most commonly affects young children under the age of 5 with a mean patient age of 5.2 years.

The most recent estimates of incidence of kidney cancer suggest that there are 63,300 new cases annually in the EU25. In Europe, kidney cancer accounts for nearly 3% of all cancer cases.

Many other complications arise from ureteroceles. Redundant collection systems are usually smaller in diameter than single, and predispose the patient to impassable kidney stones. The effective "bladder within a bladder" compounds this problem by increasing the collision of uric acid particles, the process by which uric acid stones are formed. Ureterocele is also associated with poor kidney function. It can cause frequent blockage of the ureter leading to serious kidney damage. In other cases, a small, upper portion of the kidney is congenitally non-functional. Though often benign, this problem can necessitate the removal of non-functioning parts.

The United States' NIH estimates for 2013 around 64,770 new cases of kidney cancer and 13,570 deaths from the disease.

The incidence of kidney cancer is also increasing in the United States. This is thought to be a real increase, not only due to changes in the way the disease is diagnosed.

Urethral diverticulum can occur in men, and can cause complications including kidney stones and urinary tract infections.

The incidence of urethral diverticulum has been increasing in the 2000s, likely due to increasing diagnosis and detection of the condition. It is estimated to be present in as low as 0.02% of all women and as high as 6% of all women, and 40% of women with lower urinary tract symptoms. Most symptomatic urethral diverticula are present in women from 30–60 years old.

84% of periurethral masses are due to urethral diverticula.