Overview of skin cancer

Overview 
Resources 

Last reviewed: 22 Nov 2024

Last updated: 10 Dec 2024

This page compiles our content related to skin cancer. For further information on diagnosis and treatment, follow the links below to our full BMJ Best Practice topics on the relevant conditions and symptoms.

Skin cancer is one of the most common types of cancer worldwide.[1] Possible risk factors include exposure to sunlight or ultravoilet (UV) radiation (e.g., tanning beds), other environmental exposures (e.g., arsenic), viral infection (e.g., HPV), fair skin type, presence of large numbers or certain types of nevi (moles), immunosuppression, certain genetic conditions (e.g., xeroderma pigmentosum), and family history of skin cancer.[2][3][4]

Condition	Description
Merkel cell carcinoma (MCC)	go to our full topic on Merkel cell carcinoma (MCC) MCC is a rare, aggressive cutaneous neuroendocrine neoplasm that primarily affects white adults. Incidence increases with age and is highest among those >85 years of age.[5] Two distinct etiologies are recognized: exposure to ultraviolet radiation and oncogenic transformation by Merkel cell polyomavirus. Diagnosis is confirmed with skin biopsy and histopathologic evaluation including immunohistochemistry. Occult metastasis is common, and sentinel lymph node biopsy and imaging are important tools for staging the disease.
Basal cell carcinoma	go to our full topic on Basal cell carcinoma The most common malignancy of the skin in fair-skinned adults in the US, Australia, and Europe.[6] It typically presents as pearly papules and/or plaques; nonhealing scabs; small crusts and nonhealing wounds; plaques, nodules, and tumors with rolled borders; or papules with associated telangiectasias.[7][8][Figure caption and citation for the preceding image starts]: Nodular basal cell carcinoma on the cheek, on background of diffuse solar damage with marked solar elastosisFrom the collection of Dr Robert A. Schwartz [Citation ends]. Strong risk factors include UV radiation, sun exposure, x-ray exposure, arsenic exposure, xeroderma pegmentosum, nevoid basal cell carcinoma (Gorlin-Goltz) syndrome, and history of transplantation. Metastases and advanced lesions are uncommon.
Squamous cell carcinoma	go to our full topic on Squamous cell carcinoma Ranges from in situ tumors (Bowen disease) to invasive tumors and metastatic disease. Patients commonly present with a new or englarging lesion that they are concerned about, which may be tender or itchy, or a nonhealing wound originally caused by some trauma. In situ tumors are typically thin, flesh-colored to erythematous, scaly plaques, while invasive squamous cell carcinoma (SCC) may present as an exophytic tumor or ulcer.[Figure caption and citation for the preceding image starts]: Squamous cell carcinoma on the ear with surrounding actinic damageFrom the collection of Dr Jessica M. Sheehan and Dr Keyoumars Soltani [Citation ends]. Tumors may be friable and bleed easily and are located mostly on sun-exposed areas of skin, such as the head and neck (84%) and extensor upper extremities (13%).[9] Cumulative UV exposure and immunosuppression are major risk factors.
Melanoma	go to our full topic on Melanoma A malignant tumor arising from pigment-producing melanocytes found in the skin, eye, and central nervous system. Several variants exist. Typically presents as a deeply pigmented skin lesion that is new or changing in size, shape, or color.[10][11][Figure caption and citation for the preceding image starts]: Superficial spreading malignant melanomaFrom the collection of Dr Hobart W. Walling [Citation ends]. Unlike basal cell carcinoma and squamous cell carcinoma, melanoma is most common at body sites that have received intense, intermittent sun/UV exposure.[12] Lesions are more common on the trunk in men and on the legs and feet in women.[13] Tanning beds and sun lamps have been positively correlated with melanoma.[14] The likelihood of metastatic disease as a complication is high, and in young adults melanoma is a common cause of cancer-related death.[15]
Kaposi sarcoma	go to our full topic on Kaposi sarcoma A low-grade vasoformative neoplasm associated with human herpesvirus-8 (HHV-8, also known as Kaposi sarcoma-associated herpesvirus [KSHV]) infection.[16] Lesions frequently involve mucocutaneous sites, but may become more extensive to involve the lymph nodes and visceral organs. Skin lesions evolve from an early patch, to a plaque, and later to ulcerating tumor nodules. [Figure caption and citation for the preceding image starts]: Kaposi sarcoma cutaneous purple-brown plaque on the footFrom the collection of Dr Bruce J. Dezube [Citation ends].There are four main subtypes: classic (sporadic); endemic (observed in sub-Saharan Africa); epidemic (AIDS-related); iatrogenic (transplant-related). Among people who are HIV positive, early initiation of antiretroviral therapy (ART) is likely to be the most effective measure for the prevention of Kaposi sarcoma.[17]National Institutes of Health, Centers for Disease Control and Prevention, HIV Medicine Association, and Infectious Diseases Society of America. Panel on Guidelines for the Prevention and Treatment of Opportunistic Infections in Adults and Adolescents with HIV. Guidelines for the prevention and treatment of opportunistic infections in adults and adolescents with HIV: Human herpesvirus-8 disease. 2018 [internet publication].
Cutaneous T-cell lymphoma	go to our full topic on Cutaneous T-cell lymphoma Heterogeneous group of uncommon disorders characterized by clonal accumulation of T lymphocytes primarily or exclusively in the skin. Mycosis fungoides and its leukemic variant, Sézary syndrome, are the most common subtypes.[18] Establishing a diagnosis is often difficult, as the disease can manifest in a number of different ways, including flat patches, raised plaques, large tumors, and/or marked erythroderma (intense and widespread reddening of the skin).[Figure caption and citation for the preceding image starts]: Cutaneous T-cell lymphoma: extensive patch diseaseFrom the collection of the Christie NHS Foundation Trust, Manchester, UK; used with permission [Citation ends]. Diagnosis is based on clinical findings, skin biopsy (specimens should be sent for histology, immunophenotyping, and molecular studies), and laboratory blood tests, and usually requires specialist expertise.[18][19]
Actinic keratosis	go to our full topic on Actinic keratosis Lesions are skin-colored, yellowish, or erythematous, ill-defined, irregularly shaped, small, scaly macules or plaques localized in sun-exposed areas of the body (e.g., forehead, lower lip, dorsum of the hands, forearms, bald areas of the scalp, and ears).[Figure caption and citation for the preceding image starts]: Regular actinic keratosisFrom the collection of the Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine [Citation ends]. Typically, they occur in middle-aged or older men with light-colored skin and a history of chronic sun exposure. It has the potential to progress into an invasive squamous cell carcinoma (SCC). The risk of progression to SCC has been calculated to be between 0.025% and 16% per year.[20][21] Although diagnosed clinically, a biopsy may help to rule out SCC.
Sunburn	go to our full topic on Sunburn Sunburn is an acute inflammatory reaction of the skin induced by overexposure to UV radiation. Skin findings include erythema and edema, with or without vesiculation, followed by desquamation. Symptoms include pain and/or pruritus. Acute sunburn is a self-limited condition and typically requires only supportive care. Primary prevention via sun avoidance, physical protection, and the appropriate use of sunscreen is key to managing the condition, as cellular damage caused by UV radiation is irreversible and may with time increase the risk of skin cancer.