Conjunctival squamous cell carcinoma (conjunctival SCC) and corneal intraepithelial neoplasia comprise ocular surface squamous neoplasia (OSSN). SCC is the most common malignancy of the

conjunctiva In the anatomy of the eye, the conjunctiva (: conjunctivae) is a thin mucous membrane that lines the inside of the eyelids and covers the sclera (the white of the eye). It is composed of non-keratinized, stratified squamous epithelium with gobl ...

in the US, with a yearly incidence of 1–2.8 per 100,000. Risk factors for the disease are exposure to sun (specifically occupational), exposure to

UVB Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of the ...

, and light-colored skin. Other risk factors include radiation, smoking,

HPV Human papillomavirus infection (HPV infection) is caused by a DNA virus from the ''Papillomaviridae'' family. Many HPV infections cause no symptoms and 90% resolve spontaneously within two years. In some cases, an HPV infection persists and ...

arsenic Arsenic is a chemical element; it has Symbol (chemistry), symbol As and atomic number 33. It is a metalloid and one of the pnictogens, and therefore shares many properties with its group 15 neighbors phosphorus and antimony. Arsenic is not ...

, and exposure to

polycyclic hydrocarbons A Polycyclic aromatic hydrocarbon (PAH) is any member of a class of organic compounds that is composed of multiple fused aromatic rings. Most are produced by the incomplete combustion of organic matter— by engine exhaust fumes, tobacco, inciner ...

. Conjunctival SCC is often asymptomatic at first, but it can present with the presence of a growth, red eye, pain, itching, burning, tearing, sensitivity to light, double vision, and decreased vision. Spread of conjunctival SCC can occur in 1–21% of cases, with the first site of spread being the regional lymph nodes. Mortality for conjunctival SCC ranges from 0–8%. Diagnosis is often made by biopsy, as well as CT (in the case of invasive SCC). Treatment of conjunctival SCC is usually surgical excision followed by

cryotherapy Cryotherapy, sometimes known as cold therapy, is the local or general use of low temperatures in medical therapy. Cryotherapy can be used in many ways, including whole body exposure for therapeutic health benefits or may be used locally to treat ...

. After this procedure, Conjunctival SCC can recur 8–40% of the time. Radiation treatment, topical

Mitomycin C Mitomycin C is a mitomycin that is used as a chemotherapy, chemotherapeutic agent by virtue of its antitumour activity. Medical uses It is given intravenously to treat upper gastro-intestinal cancers (e.g. esophageal carcinoma), anal cancer ...

, and removal of the contents of the orbit, or exenteration, are other methods of treatment. Close follow-up is recommended, because the average time to recurrence is 8–22 months.

Classification

Cancer can be considered a very large and exceptionally heterogeneous family of malignant diseases, with squamous cell carcinomas comprising one of the largest subsets.

Terminology

All squamous cell carcinoma lesions are thought to begin via the repeated, uncontrolled division of cancer

stem cells In multicellular organisms, stem cells are undifferentiated or partially differentiated cells that can change into various types of cells and proliferate indefinitely to produce more of the same stem cell. They are the earliest type of cell ...

of epithelial lineage or characteristics. Accumulation of these cancer cells causes a microscopic focus of abnormal cells that are, at least initially, locally confined within the specific tissue in which the progenitor cell resided. This condition is called squamous cell carcinoma ''in situ'', and it is diagnosed when the tumor has not yet penetrated the

basement membrane The basement membrane, also known as base membrane, is a thin, pliable sheet-like type of extracellular matrix that provides cell and tissue support and acts as a platform for complex signalling. The basement membrane sits between epithelial tis ...

or other delimiting structure to invade adjacent tissues. Once the lesion has grown and progressed to the point where it has breached, penetrated, and infiltrated adjacent structures, it is referred to as " invasive" squamous cell carcinoma. Once a carcinoma becomes invasive, it is able to spread to other organs and cause a

metastasis Metastasis is a pathogenic agent's spreading from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, ...

, or "secondary tumor", to form.

Signs and symptoms

Causes

Human papilloma virus

Diagnosis

The differential for OSSN includes

pterygium A pterygium (: ''pterygia'' or ''pterygiums'') is any wing-like triangular membrane occurring in the neck, eyes, knees, elbows, ankles or digits. The term comes from the Greek word ''pterygion'' meaning "wing". Types * Popliteal pterygium syn ...

, pingueculum,

papilloma A papilloma (plural papillomas or papillomata) ('' papillo-'' + '' -oma'') is a benign epithelial tumor growing exophytically (outwardly projecting) in nipple-like and often finger-like fronds. In this context, papilla refers to the projection cr ...

solar keratosis Actinic keratosis (AK), sometimes called solar keratosis or senile keratosis, is a pre-cancerous area of thick, scaly, or crusty skin.Freedberg, et al. (2003). ''Fitzpatrick's Dermatology in General Medicine''. (6th ed.). McGraw-Hill. . Actin ...

lipoma A lipoma is a benign tumor made of adipose tissue, fat tissue. They are generally soft to the touch, movable, and painless. They usually occur just under the skin, but occasionally may be deeper. Most are less than in size. Common locations inc ...

lymphoma Lymphoma is a group of blood and lymph tumors that develop from lymphocytes (a type of white blood cell). The name typically refers to just the cancerous versions rather than all such tumours. Signs and symptoms may include enlarged lymph node ...

, chronic blepharoconjunctivitis,

inflammation Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...

melanoma Melanoma is the most dangerous type of skin cancer; it develops from the melanin-producing cells known as melanocytes. It typically occurs in the skin, but may rarely occur in the mouth, intestines, or eye (uveal melanoma). In very rare case ...

, ocular

pannus Pannus is an abnormal layer of fibrovascular tissue or granulation tissue. Common sites for pannus formation include over the cornea, over a joint surface (as seen in rheumatoid arthritis), or on a prosthetic heart valve. Pannus may grow in a t ...

pyogenic granuloma A pyogenic granuloma or lobular capillary hemangioma is a vascular tumor that occurs on both mucosa and skin, and appears as an overgrowth of tissue due to irritation, physical trauma, or hormonal factors. It is often found to involve the gums, ...

kaposi sarcoma Kaposi's sarcoma (KS) is a type of cancer that can form masses on the skin, in lymph nodes, in the mouth, or in other organs. The skin lesions are usually painless, purple and may be flat or raised. Lesions can occur singly, multiply in a limite ...

keratocanthoma Keratoacanthoma (KA) is a common low-grade (unlikely to metastasize or invade) rapidly-growing skin tumour that is believed to originate from the hair follicle (pilosebaceous unit) and can resemble squamous cell carcinoma. The defining characteris ...

, mucoepidermoid carcinoma, pseudoepitheliomatous hyperplasia, and adenocarcinoma. While

confocal microscopy Confocal microscopy, most frequently confocal laser scanning microscopy (CLSM) or laser scanning confocal microscopy (LSCM), is an optical imaging technique for increasing optical resolution and contrast (vision), contrast of a micrograph by me ...

can be used for diagnosis, biopsy is considered the standard, especially before treatment with a cytotoxic medication.

Management

Most conjunctival squamous cell carcinomas are removed with surgery. A few selected cases are treated with

topical A topical medication is a medication that is applied to a particular place on or in the body. Most often topical medication means application to body surfaces such as the skin or mucous membranes to treat ailments via a large range of classes ...

medication. Surgical excision with a

free margin A resection margin or surgical margin is the edge or "margin" of apparently non-tumorous tissue around a tumor that has been surgically removed, called " resected", in surgical oncology. The resection is an attempt to remove a cancer tumor so th ...

of healthy tissue is a frequent treatment modality. Radiotherapy, given as

external beam radiotherapy External beam radiation therapy (EBRT) is a form of radiotherapy that utilizes a high-energy collimated beam of ionizing radiation, from a source outside the body, to target and kill cancer cells. The radiotherapy beam is composed of particl ...

or as

brachytherapy Brachytherapy is a form of radiation therapy where a sealed radiation, radiation source is placed inside or next to the area requiring treatment. The word "brachytherapy" comes from the Ancient Greek, Greek word , meaning "short-distance" or "s ...

(internal radiotherapy), can also be used to treat squamous cell carcinomas.

In animals

Squamous cell carcinoma Squamous-cell carcinoma (SCC), also known as epidermoid carcinoma, comprises a number of different types of cancer that begin in squamous cells. These cells form on the surface of the skin, on the lining of hollow organs in the body, and on the ...

eye An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the ey ...

tissues is one of the most frequent

neoplasm A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

s of

cattle Cattle (''Bos taurus'') are large, domesticated, bovid ungulates widely kept as livestock. They are prominent modern members of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Mature female cattle are calle ...

. File:Crantche e l' ouy vatche troejhinme påpire.jpg, On third eyelid, papilloma-like (see hairs) File:Crantche ouy noere pea.jpg, invading conjunctival tissues

References

External links

{{DEFAULTSORT:Squamous Cell Carcinoma Anatomical pathology Head and neck cancer Epidermal nevi, neoplasms, and cysts Carcinoma ca:Carcinoma escatós de:Plattenepithelkarzinom dv:ސްކްއޭމަސް ސެލް ކެންސަރު es:Carcinoma espinocelular fr:Carcinome épidermoïde hi:स्क्वैमस सेल कार्सिनोमा (शल्की सेल कैंसर) it:Carcinoma cutaneo spinocellulare he:קרצינומת תאי קשקש nl:Plaveiselcelcarcinoom ja:扁平上皮癌 pl:Rak kolczystokomórkowy skóry pt:Carcinoma de células escamosas sv:Skivepitelcancer te:స్క్వామస్ సెల్ కార్సినోమా tr:Skuamöz hücreli karsinom