Verrucous carcinoma (VC) is an uncommon variant of squamous cell carcinoma. This form of cancer is often seen in those who chew tobacco or use snuff orally, so much so that it is sometimes referred to as "Snuff dipper's cancer."

Most patients with verrucous carcinoma have a good prognosis. Local recurrence is not uncommon, but metastasis to distant parts of the body is rare. Patients with oral verrucous carcinoma may be at greater risk of a second oral squamous cell carcinoma, for which the prognosis is worse.

Verrucous carcinoma may occur in various head and neck locations, as well as in the genitalia. The oral cavity is the most common site of this tumor. The ages range from 50 to 80 years with a male predominance and a median age of 67 years. VC may grow large in size, resulting in the destruction of adjacent tissue, such as bone and cartilage.

The diagnosis of VC is established by close communication between surgeons and pathologists.

Surgeons must provide adequate specimens including the full thickness of the tumors and adjacent uninvolved mucosa for correct diagnoses.

Surgery is considered as the treatment of choice, but the extent of surgical margin and the adjuvant radiotherapy are still controversial.

The major risk factors are cigarette smoking and alcohol consumption, while betel nut is an additional factor in Taiwan. Different gene mutation sites in head and neck cancer between western countries and Taiwan have been reported. The presentation of VC originated from exposure to different carcinogens may not be the same.

Medically speaking, the term denotes a squamous intraepithelial lesion of the vulva that shows dysplasia with varying degrees of atypia. The epithelial basement membrane is intact and the lesion is thus not invasive but has invasive potential.

The terminology of VIN evolved over several decades. In 1989 the Committee on Terminology, International Society for the Study of Vulvar Disease (ISSVD) replaced older terminology such as vulvar , Bowen's disease, and Kraurosis vulvae by a new classification system for "Epithelial Vulvar Disease":

- Nonneoplastic epithelial disorders of vulva and mucosa:

- Lichen sclerosus

- Squamous hyperplasia

- Other dermatoses

- Mixed neoplastic and nonneoplastic disorders

- Intraepithelial neoplasia

- Squamous vulvar intraepithelial neoplasia (VIN)

- VIN I, mildest form

- VIN II, intermediate

- VIN III, most severe form including carcinoma in situ of the vulva

- Non-squamous intraepithelial neoplasia

- Extramammary Paget's disease

- Tumors of melanocytes, noninvasive

- Invasive disease (vulvar carcinoma)

The ISSVD further revised this classification in 2004, replacing the three-grade system with a single-grade system in which only the high-grade disease is classified as VIN.

VIN is subdivided into: (Robbins Pathological Basis of Disease, 9th Ed)

Classic vulvular intraepithelial neoplasia: associated with developing into the warty and basaloid type carcinoma. This is associated with carcinogenic genotypes of HPV and/or HPV persistence factors such as cigarette smoking or immunocompromised states.

Differentiated vulvar intraepithelial neoplasia also known as VIN Simplex: is associated with vulvar dermatoses such as lichen sclerosus. It is associated with atypia of the squamous epithelium.

Basophilic, bland cells similar to acinar cells. Growth pattern: solid - acinar cells, microcytic - small systic spaces mucinous or eosinophilic, papillary-cystic - large cystic lined by epithelium, follicular - similar to thyroid tissue.

These tumors which resemble serous acinar cells vary in their behavior from locally aggressive to blatantly malignant.

It can also appear in the breast. The pancreatic form of acinic cell carcinoma is a rare subtype of exocrine pancreatic cancer. Exocrine pancreatic cancers are the most common form of pancreatic cancer when compared to endocrine pancreatic cancer.

Acinic cell carcinomas arise most frequently in the parotid gland. Other sites of primary tumors have included the submandibular gland and other major and minor salivary glands. There have been rare cases of primary tumors involving the parapharyngeal space and the sublingual gland.

The patient may have no symptoms, or local symptomatology including itching, burning, and pain.

The diagnosis is always based on a careful inspection and a targeted biopsy of a visible vulvar lesion.

The type and distribution of lesions varies among the two different types of VIN. In the Usual type VIN, seen more frequently in young patients, lesions tend to be multifocal over an otherwise normal vulvar skin. In the differentiated type VIN, usually seen in postmenopausal women, lesions tend to be isolated and are located over a skin with a vulvar dermatosis such as Lichen slerosus.

Acinic cell carcinoma appears in all age groups, but presents at a younger median age (approx. 52 years) than most other salivary gland cancers. Occurrences in children are quite common.

Although often the terms "erythroplasia" and "erythroplakia" are used synonymously, some sources distinguish them, stating that the latter is maccular (flat) while the former is papular (bumpy).

Erythroplakia of the genital mucosae is often referred to as erythroplasia of Queyrat.

The most common areas in the mouth where erythroplakia is found are the floor of the mouth, buccal vestibule, the tongue, and the soft palate. It appears as a red macule or plaque with well-demarcated borders. The texture is characterized as soft and velvety. An adjacent area of leukoplakia may be found along with the erythroplakia.

Erythroplasia may also occur on the laryngeal mucosa, or the anal mucosa.

Most cases of leukoplakia cause no symptoms, but infrequently there may be discomfort or pain. The exact appearance of the lesion is variable. Leukoplakia may be white, whitish yellow or grey. The size can range from a small area to much larger lesions. The most common sites affected are the buccal mucosa, the labial mucosa and the alveolar mucosa, although any mucosal surface in the mouth may be involved. The clinical appearance, including the surface texture and color, may be homogenous or non-homogenous (see: classification). Some signs are generally associated with a higher risk of cancerous changes (see: prognosis).

Leukoplakia may rarely be associated with esophageal carcinoma.

In the context of lesions of the mucous membrane lining of the bladder, leukoplakia is a historic term used to describe a visualized white patch which histologically represents keratinization in an area of squamous metaplasia. The symptoms may include frequency, suprapubic pain (pain felt above the pubis), hematuria (blood in the urine), dysuria (difficult urination or pain during urination), urgency, and urge incontinence. The white lesion may be seen during cystoscopy, where it appears as a whitish-gray or yellow lesion, on a background of inflamed urothelium and there may be floating debris in the bladder. Leukoplakia of the bladder may undergo cancerous changes, so biopsy and long term follow up are usually indicated.

It presents itself in the mouth, most frequently as a thick, bilateral, symmetrical white plaques with a spongy, corrugated or velvety texture. Most usually, the lesions are on the buccal mucosa, but sometimes on the labial mucosa, alveolar ridge, floor of the mouth, ventral surface of the tongue or soft palate. The gingival margin and dorsum of the tongue are almost never affected. Less commonly, sites outside the mouth are affected, including the nasal, esophageal, laryngeal, anal and genital mucosae. It usually is present from birth, or develops during childhood. Rarely, the lesions may develop during adolescence. Apart from the appearance of the affected areas, there are usually no other signs or symptoms.

There are many other conditions that are similar in appearance and must be ruled out before a diagnosis of erythroplakia is made (see table). Sometimes, a diagnosis is delayed for up to two weeks in order to see if the lesion spontaneously regresses on its own or if another cause can be found. Erythroplakia frequently is associated with dysplasia, and is thus a precancerous lesion.

AMS has been described by multiple authors and institutions, and various definitions have been adopted. According to Newton et al., a scoring system allotting one point per feature establishes AMS with scores greater than or equal to 3. The features include: 1) two or more clinically atypical nevi, 2) more than 100 nevi in patients between 20 and 50 years of age, 3) more than 50 nevi in patients under 20 years of age or more than 50 years of age, 4) more than one nevus in buttocks or instep, 5) nevi on the anterior scalp, 6) one or more pigmented lesions in the iris.

The Classical (1990) definition uses the following criteria: 1) 100 or more melanocytic nevi, 2) one or more melanocytic nevi greater than or equal to 8mm in its largest diameter, and 3) one or more clinically atypical melanocytic nevi.

The National Institutes of Health (NIH) Consensus 1992 definition, which is still controversial, requires a family history of melanoma, in addition to a large number of melanocytic nevi (often greater than 50) and melanocytic nevi that present certain histological features.

People over 20 years of age with Birt–Hogg–Dubé syndrome have an increased risk of developing slow-growing kidney tumors (chromophobe renal carcinoma and renal oncocytoma, respectively), kidney cysts, and possibly tumors in other organs and tissues. These tumors often occur in both kidneys and in multiple locations in each kidney. The average number of kidney tumors found in a person with BHD is 5.3, though up to 28 tumors have been found. Hybrid oncocytoma/chromophobe carcinoma, found in 50% of cases, is the most commonly found cancer, followed by chromophobe renal carcinoma, clear cell renal carcinoma, renal oncocytoma, and papillary renal cell carcinoma. People over 40 years old and men are more likely to develop kidney tumors, which are diagnosed at a median age of 48. Kidney cancer associated with BHD have been diagnosed in people at ages as young as 20.

In general, people with Birt–Hogg–Dubé syndrome are at roughly seven times the risk of kidney cancer compared to the unaffected population. Estimates of the incidence among people with the disease range from 14%–34%. Rarely, it is associated with clear cell renal cell carcinoma and papillary renal cell carcinoma. If it develops in someone with BHD, renal cell carcinoma occurs later in life and has a poor prognosis. Though the types of tumor typically associated with BHD are considered less aggressive, cases of advanced or metastatic kidney cancer have been observed in people with the syndrome. Both benign and cancerous tumors can reduce kidney function over time as they grow larger.

Birt–Hogg–Dubé syndrome affects the skin and increases the risk of tumors in the kidneys and lungs. The condition is characterized by multiple noncancerous dome-shaped tumors of the hair follicles (fibrofolliculomas), particularly on the face, neck, and—more rarely—the upper chest. The fibrofolliculomas are generally described as having an opaque white color or a yellowish tone and have a waxy, smooth texture. The tumors are always found on and around the nose and on and behind the outer ear. Typically, they first appear in a person's 20s or 30s, and are found in more than 80% of people with the syndrome above the age of 40. The tumors become larger and more numerous over time. Tumors differ between individuals: they may appear merged in plaques, look similar to a comedo with a plug of keratin, or include epidermoid cysts. A large number of tumors on the face can be associated with hyperseborrhea (abnormally elevated sebum production). The presence of fibrofolliculomas on a person's face can cause significant psychological distress.

Other tumors can include trichodiscomas (tumors of the hair disc, which may be identical to fibrofolliculomas), angiofibromas, and perifollicular fibromas. However, angiofibromas are more common in tuberous sclerosis. Along with the tumors, other skin conditions are seen in people with Birt–Hogg–Dubé syndrome. Approximately 40% of people or families with the disease have papules in their mouth, which can be located on the cheeks (buccal mucosa), tongue, gums, or lips. Either white or mucosa-colored, they are discrete, small, and soft and consist of fibrous tissue covered in thickened epithelium. Collagenomas of the skin are also found in some families. Many people with BHD have skin lesions that appear to be acrochordons (skin tags), but may instead be fibrofolliculomas. These lesions are usually found in the armpit, on the eyelids, and in folds of skin. Not all individuals develop the facial tumors; some families with the mutation that causes BHD develop only kidney tumors or spontaneous pneumothorax.

White sponge nevus (WSN, or white sponge naevus, Cannon's disease, hereditary leukokeratosis of mucosa, white sponge nevus of Cannon, familial white folded dysplasia, or oral epithelial nevus), is an autosomal dominant condition of the oral mucosa (the mucous membrane lining of the mouth). It is caused by a mutations in certain genes coding for keratin, which causes a defect in the normal process of keratinization of the mucosa. This results in lesions which are thick, white and velvety on the inside of the cheeks within the mouth. Usually, these lesions are present from birth or develop during childhood. The condition is entirely harmless, and no treatment is required.

The lesion is usually painless. The usual appearance is of two excess tissue folds in alveolar vestibule/buccal sulcus, with the flange of the denture fitting in between the two folds. It may occur in either the maxillary or mandibular sulci, although the latter is more usual. Anterior locations are more common than posterior. Less commonly there may be a single fold, and the lesion may appear on the lingual surface of the mandibular alveolar ridge.

The swelling is firm and fibrous, with a smooth, pink surface. The surface may also show ulceration or erythema. The size of the lesion varies from less than 1 cm to involving the entire length of the sulcus.

The lesion is found in patients who present typically with abnormal or postmenopausal bleeding or discharge. Such bleeding is followed by further evaluation leading to a tissue diagnosis, usually done by a dilatation and curettage (D&C). A work-up to follow would look for metastasis using imaging technology including sonography and MRI. The median age at diagnosis in a large study was 66 years. Histologically the lesion may coexist with classical endometrial cancer.

The risks associated with this syndrome include a strong tendency of developing cancer in a number of parts of the body. While the hamartomatous polyps themselves only have a small malignant potential (<3% - OHCM), patients with the syndrome have an increased risk of developing carcinomas of the pancreas, liver, lungs, breast, ovaries, uterus, testicles and other organs.

The average age of first diagnosis is 23, but the lesions can be identified at birth by an astute pediatrician or family physician. Prior to puberty, the mucocutaneous lesions can be found on the palms and soles. Often the first presentation is a bowel obstruction from an intussusception which is a common cause of mortality; an intussusception is a telescoping of one loop of bowel into another segment.

Epulis (literally, 'on the gingiva') is a general term for any gingival or alveolar tumor (i.e. lump on the gum). This term describes only the location of a lump and has no implication on the histologic appearance of a lesion. "Epulis" is also sometimes used synonymously with epulis fissuratum, however other conditions are classified as epulides, e.g. giant cell epulis (peripheral giant cell granuloma), ossifying fibroid epulis (peripheral ossifying fibroma), and congenital epulis.

Mammary analogue secretory carcinoma (MASC) (also termed MASC; the "SG" subscript indicates salivary gland)) is a salivary gland neoplasm that shares a genetic mutation with certain types of breast cancer. MASC was first described by Skálová et al. in 2010. The authors of this report found a chromosome translocation in certain salivary gland tumors that was identical to the (12;15)(p13;q25) fusion gene mutation found previously in secretory carcinoma, a subtype of invasive ductal carcinoma of the breast.

The histopathologic characteristics of melanoma in FAMMM kindreds are not different from those seen in sporadic cases of melanoma and, thus, are not useful in diagnosing the syndrome. Superficial spreading melanoma (SSM) and nodular melanoma are the most frequently encountered histological melanoma subtypes in patients with CDKN2A mutations, which is consistent with the relative early age of onset.

There is a diffuse, gray-white, milky opalescent appearance of the mucosa which usually occurs bilaterally on the buccal mucosa. Less often, the labial mucosa, the palate or the floor of mouth may be affected. The surface of the area is folded, creating a wrinkled, white streaked lesion. Apart from the appearance, the lesion is entirely asymptomatic.

This form of cancer is often seen in those who chew tobacco or use snuff orally, so much so that it is sometimes referred to as "Snuff dipper's cancer." Chewing betel nuts is an additional risk factor commonly seen in Taiwan.

Cystitis glandularis arises from and merges with Von Brunn's nests, which are groups of urothelial cells (cells of urinary tract) within the lamina propria and submucosa, formed from budding from the surface mucosa. They are considered normal. Cystitis cystica is a similar lesion to cystitis glandularis, where the central area of the Von Brunn's nests have degenerated, leaving cystic lesions. Other metaplastic entities in the urinary bladder include squamous metaplasia and nephrogenic adenoma.

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.

Neuroendocrine carcinoma affects many different parts of the body.

In the cervix, it is a rare, but very aggressive form of cervical cancer. In its early stages, neuroendocrine carcinoma is asymptomatic (not showing or producing indications of a disease or other medical condition). In more advanced stages, symptoms of Neuroendocrine carcinoma of the cervix are: abnormal vaginal bleeding, increased vaginal discharge, and pelvic pain, painful urination, pain during sex, tiredness, leg swelling, and backache. When left untreated, metastasis or even death may occur.