{"entity":{"id":"bowens-disease","kind":"cancer","name":"Bowen's disease (squamous cell carcinoma in situ)","aka":["Bowen disease","Bowen's disease","squamous cell carcinoma in situ","SCC in situ","cutaneous squamous cell carcinoma in situ","intraepidermal carcinoma","intraepidermal squamous cell carcinoma","in situ skin cancer","stage 0 skin cancer","D04"],"tldr":"Bowen's disease is the earliest form of squamous cell skin cancer: abnormal cells fill the outer layer of the skin but have not broken through it, so it cannot spread. It looks like a red, scaly patch, often on the lower leg, and it is usually cured by a cream, freezing, light treatment or a small operation.","summary":"What it is. Bowen's disease is squamous cell carcinoma in situ of the skin. The keratinocytes of the epidermis have become malignant across its full thickness, but the basement membrane beneath them is intact, so there is nothing for the cancer to spread through: no blood vessels and no lymphatics reach into the epidermis. Cancer Research UK describes it as pre-invasive and as a very early form of non-melanoma skin cancer that grows very slowly. In the staging system UK reports use it is the pTis category, which is stage 0.\n\nHow it differs from its parent. Invasive cutaneous squamous cell carcinoma has broken through the basement membrane into the dermis and can therefore reach lymph nodes; Bowen's disease has not and cannot. That single structural difference is the whole of the difference in outlook, and it is why the treatments are different: a lesion that cannot spread can be treated with something that destroys the epidermis, such as a cream, cryotherapy or photodynamic therapy, where an invasive cancer needs the tissue beneath it removed and examined. It differs from actinic keratosis in the other direction: an actinic keratosis is dysplasia in sun-damaged skin and is not a neoplasm at all in ICD-10, while Bowen's disease is a carcinoma, coded in the neoplasm chapter.\n\nHow it looks and where. Usually red scaly patches; the skin may look red and sore, and as the patches enlarge they can become crusty or turn into an open sore. It most often appears on the head, neck, arms, trunk and the legs, particularly the lower legs, although it can occur anywhere. The lower leg in an older woman is the classic site and also the most awkward, because skin there heals slowly, which is one of the reasons treatment is often chosen to avoid surgery.\n\nHow it is treated and what happens next. Cancer Research UK lists topical fluorouracil or imiquimod, cryotherapy, curettage and cautery, surgical excision, Mohs surgery, photodynamic therapy, radiotherapy and laser, and says that all of these can work well, with high cure rates. It has a UK national guideline of its own, the British Association of Dermatologists guidelines for the management of people with cutaneous squamous cell carcinoma in situ, published in 2022, whose first line of definition is that Bowen disease is a form of intraepidermal, in situ, squamous cell carcinoma, originally described in 1912.\n\nHow often it becomes invasive, and why two very different numbers are both right. The figure most often quoted is per lesion: the earlier British guideline stated that most studies suggest a risk of invasive carcinoma of about 3 to 5 percent for typical squamous cell carcinoma in situ, and about 10 percent for erythroplasia of Queyrat, the form on the glans penis (Morton 2014); Cancer Research UK gives the same 3 to 5 in 100 and says that most Bowen's disease does not progress. The figure the 2022 guideline cites instead is per person and counts a cancer anywhere on the body: in a Dutch national cohort of 88,754 people with squamous cell carcinoma in situ, the cumulative risk of developing an invasive squamous cell carcinoma at any site within 5 years was 11.7 percent in men and 6.9 percent in women, and the excess over the general population was highest in the first year of follow-up (Tokez 2020). Those two statements are not in conflict. The patch on the leg is very unlikely to turn into a cancer; the person who grew that patch has skin that is likely to grow a cancer somewhere.","asOf":"2026-09-25","wikipedia":"https://en.wikipedia.org/wiki/Bowen%27s_disease","links":[{"label":"Cancer Research UK: Bowen's disease","url":"https://www.cancerresearchuk.org/about-cancer/skin-cancer/types/bowens-disease"},{"label":"Sharma et al., British Journal of Dermatology 2023;188:186 to 194: British Association of Dermatologists guidelines for the management of people with cutaneous squamous cell carcinoma in situ (Bowen disease) 2022","url":"https://doi.org/10.1093/bjd/ljac042"},{"label":"Morton et al., British Journal of Dermatology 2014;170(2):245 to 260: British Association of Dermatologists' guidelines for the management of squamous cell carcinoma in situ (Bowen's disease) 2014, superseded by the 2022 version","url":"https://doi.org/10.1111/bjd.12766"},{"label":"Tokez, Wakkee, Kuijpers et al., JAMA Dermatology 2020;156(9):973 to 981: incidence of cutaneous squamous cell carcinoma in situ and the risk of developing invasive disease, 88,754 patients, the Netherlands 1989 to 2017","url":"https://doi.org/10.1001/jamadermatol.2020.1988"},{"label":"Royal College of Pathologists G124: dataset for histopathological reporting of primary invasive cutaneous squamous cell carcinoma and regional lymph nodes, version 4, February 2019 (Slater and Barrett)","url":"https://www.rcpath.org/resourceLibrary/g124datasetsquamous-pdf.html"},{"label":"WHO ICD-10 (2019): C43 to C44 melanoma and other malignant neoplasms of skin; D04 carcinoma in situ of skin; L57.0 actinic keratosis, under skin changes due to chronic exposure to nonionizing radiation","url":"https://icd.who.int/browse10/2019/en"},{"label":"IARC and the International Association of Cancer Registries: ICD-O-3.2 morphology and behaviour codes (actinic keratosis 8070/0; Bowen disease 8081/2; keratoacanthoma a related term under 8071/3; micronodular basal cell carcinoma shares 8097/3 with nodular, and sclerosing or morphoeic shares 8092/3 with infiltrating)","url":"http://www.iacr.com.fr/index.php?option=com_content&view=category&layout=blog&id=100&Itemid=577"},{"label":"van Bodegraven et al., British Journal of Dermatology 2023;188(6):777 to 784: 'Get Data Out' Skin, national cancer registry incidence and survival rates for all registered skin tumour groups for 2013 to 2019 in England","url":"https://doi.org/10.1093/bjd/ljad033"},{"label":"Royal College of Pathologists appendix A, version 3, 6 November 2025: UICC TNM 9 pathological staging of primary cutaneous carcinoma (basal cell), combining the UICC chapters for skin carcinoma of the head and neck and carcinoma of the skin","url":"https://www.rcpath.org/resourceLibrary/basal-cell-tnm9.html"},{"label":"WHO Classification of Tumours Editorial Board: Skin tumours, 5th edition, volume 12 (IARC, Lyon, 2025), ISBN 978-92-832-4535-3","url":"https://publications.iarc.who.int/Book-And-Report-Series/Who-Classification-Of-Tumours/Skin-Tumours-2025"},{"label":"Office for National Statistics: cancer registration statistics quality and methodology information (the statement that non-melanoma skin cancer is greatly under-registered, and that all-cancer figures are ICD-10 C00 to C97 excluding C44), last revised 23 February 2016","url":"https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/methodologies/cancerregistrationstatisticsqmi"}],"tags":["skin","subtype-page"],"related":["cutaneous-scc","basal-cell-carcinoma","skin-cancer","advanced-cutaneous-scc"],"cancers":[],"sections":[],"technologies":["histopathology-ihc","dermoscopy-ai"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["actinic-keratosis","keratinocyte-cancer","keratinocyte-cancer-counting","cscc-subtype-and-grade","tnm-skin-carcinoma","skin-cancer-high-risk-features","carcinoma-in-situ","in-situ"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":["Is Bowen's disease cancer? The honest answer is that it is a carcinoma that cannot spread. It is coded 8081/2 in ICD-O, where the final digit means in situ, and D04, carcinoma in situ of skin, in the neoplasm chapter of ICD-10; it is staged as pTis, stage 0, by the system UK reports use; and pathologists call it squamous cell carcinoma in situ. And it is described by Cancer Research UK as pre-invasive, because the malignant cells are trapped above the basement membrane. Both halves of that are true at once, and a person told they have it has been told something that needs treating and not something that threatens their life.","Why this has a page and actinic keratosis does not, and why the answer did not change when WHO changed its mind. The corpus draws the line at the behaviour code and the registration: actinic keratosis is 8070/0, benign, and L57.0, outside the neoplasm chapter, and is registered as cancer nowhere in the UK; Bowen's disease is 8081/2, in situ, and D04, and the Office for National Statistics states that all in-situ neoplasms, D00 to D09, are registered. That line held when the fifth edition of the WHO skin classification, published in 2025, moved squamous cell carcinoma in situ out of the carcinomas section of its skin chapter and in beside actinic keratosis under carcinoma precursors and benign simulants, where the fourth edition of 2018 had filed it with the carcinomas. WHO moved the heading; the behaviour code, the registration and the guideline did not move, and neither did this page. The reasoning is set out in docs/CANCER-PAGES.md so the next borderline case is decided the same way.","Registered is not the same as counted. The Office for National Statistics registers in-situ neoplasms, and then defines all cancers as ICD-10 C00 to C97 excluding C44, which excludes both the invasive keratinocyte cancers and, being a range of C codes, anything coded D04. So Bowen's disease is recorded and then does not appear in any headline cancer figure, which is the same fate as its invasive parent for a different reason.","Why the name is a person's. John Templeton Bowen described the condition in 1912, and the eponym has outlived several attempts to replace it with the accurate description, squamous cell carcinoma in situ. Both appear on British letters, and they mean the same thing. If the report says intraepidermal carcinoma, that is also the same thing."],"group":"skin","burden":"There is no dependable UK figure, and the reason is structural rather than accidental. Bowen's disease is carcinoma in situ, coded D04 in ICD-10 and not C44, so it falls outside the non-melanoma skin cancer totals, which are themselves counted on a rule that misses repeat tumours; and it falls outside the all-cancer total too, which the Office for National Statistics defines as C00 to C97 excluding C44. The English registry registers it, because all in-situ neoplasms D00 to D09 are registered, but registration is not the same as appearing in a published figure. Any number quoted for how common it is should be read beside the counting caveat that governs this whole family.","subtypes":[],"biomarkers":["The word 'in situ' or 'intraepidermal' on the report, which is the whole diagnosis: the basement membrane is intact","pTis in the UICC staging system UK reports use, which is stage 0","Basaloid Bowen's disease, which may be the origin of the basaloid variant of invasive squamous cell carcinoma and stains weakly to focally with BerEP4 (RCPath G124)","Whether invasive squamous cell carcinoma is present alongside it, which changes the diagnosis to the invasive cancer and is itself treated as a high-risk feature"],"standardOfCare":[{"setting":"Typical lesion","approach":"Topical fluorouracil or imiquimod, cryotherapy, curettage and cautery, photodynamic therapy, surgical excision, Mohs surgery, radiotherapy or laser; Cancer Research UK states that all of these can work well and that cure rates are high. The choice is driven by the site, the size, how well the skin there heals and what the person can manage at home. The treatment layer of this family carries the detail.","refs":["fluorouracil","imiquimod","aminolevulinic-acid","mohs-surgery"],"guideline":{"version":"British Association of Dermatologists guidelines for the management of people with cutaneous squamous cell carcinoma in situ (Bowen disease) 2022","url":"https://doi.org/10.1093/bjd/ljac042"}},{"setting":"If invasion is found","approach":"The diagnosis becomes invasive cutaneous squamous cell carcinoma and is managed on that pathway, with the adjacent Bowen's disease itself usually counted as a high-risk feature of the invasive tumour (RCPath G124). See the cutaneous squamous cell carcinoma page.","refs":["wide-local-excision","mohs-surgery"]}],"stateOfArt":[],"history":[],"pipeline":[],"openProblems":["Nobody knows how common it is. Carcinoma in situ of the skin sits outside the non-melanoma skin cancer totals, and those totals are themselves counted on a rule that misses repeat tumours, so there is no dependable national figure for a diagnosis many thousands of people are given every year.","The 3 to 5 percent who progress cannot be identified in advance. There is no marker that separates the lesion that will become invasive from the one that will not, so everybody is treated, and most of that treatment is for lesions that would never have caused harm.","The lower leg is the commonest site and the hardest to treat, because wounds there heal slowly in the people who most often have the disease. The evidence base for choosing between the destructive treatments at that site is thin."],"parent":"cutaneous-scc"},"route":"/cancers/bowens-disease/","neighbours":{"cancer":[{"id":"advanced-cutaneous-scc","kind":"cancer","name":"Advanced cutaneous squamous cell carcinoma","route":"/cancers/advanced-cutaneous-scc/"},{"id":"basal-cell-carcinoma","kind":"cancer","name":"Basal cell carcinoma","route":"/cancers/basal-cell-carcinoma/"},{"id":"cutaneous-scc","kind":"cancer","name":"Cutaneous squamous cell carcinoma","route":"/cancers/cutaneous-scc/"},{"id":"skin-cancer","kind":"cancer","name":"Skin cancer (all types)","route":"/cancers/skin-cancer/"}],"technology":[{"id":"dermoscopy-ai","kind":"technology","name":"Dermoscopy, total-body photography & AI skin analysis","route":"/technologies/dermoscopy-ai/"},{"id":"histopathology-ihc","kind":"technology","name":"Histopathology & immunohistochemistry","route":"/technologies/histopathology-ihc/"}],"term":[{"id":"actinic-keratosis","kind":"term","name":"Actinic keratosis (solar keratosis): sun damage, not cancer","route":"/terms/actinic-keratosis/"},{"id":"carcinoma-in-situ","kind":"term","name":"Carcinoma in situ (CIS)","route":"/terms/carcinoma-in-situ/"},{"id":"tnm-skin-carcinoma","kind":"term","name":"How skin carcinoma is staged in Britain: UICC TNM, and why it is not the American system","route":"/terms/tnm-skin-carcinoma/"},{"id":"in-situ","kind":"term","name":"In situ","route":"/terms/in-situ/"},{"id":"inherited-skin-cancer-syndromes","kind":"term","name":"Inherited syndromes that cause skin cancer: Gorlin syndrome and xeroderma pigmentosum","route":"/terms/inherited-skin-cancer-syndromes/"},{"id":"keratinocyte-cancer","kind":"term","name":"Keratinocyte cancer (and why 'non-melanoma skin cancer' is being retired)","route":"/terms/keratinocyte-cancer/"},{"id":"keratoacanthoma","kind":"term","name":"Keratoacanthoma: the tumour that may be a squamous cell carcinoma","route":"/terms/keratoacanthoma/"},{"id":"mohs-surgery","kind":"term","name":"Mohs surgery","route":"/terms/mohs-surgery/"},{"id":"perineural-invasion","kind":"term","name":"Perineural invasion (PNI)","route":"/terms/perineural-invasion/"},{"id":"squamous-cell-carcinoma","kind":"term","name":"Squamous cell carcinoma","route":"/terms/squamous-cell-carcinoma/"},{"id":"cscc-subtype-and-grade","kind":"term","name":"The subtype and grade on a cutaneous squamous cell carcinoma report","route":"/terms/cscc-subtype-and-grade/"},{"id":"skin-cancer-high-risk-features","kind":"term","name":"What makes a skin cancer high risk: the UK feature lists","route":"/terms/skin-cancer-high-risk-features/"},{"id":"keratinocyte-cancer-counting","kind":"term","name":"Why nobody knows how many skin cancers there are: the counting rule behind every figure","route":"/terms/keratinocyte-cancer-counting/"},{"id":"wide-local-excision","kind":"term","name":"Wide local excision","route":"/terms/wide-local-excision/"}],"drug":[{"id":"aminolevulinic-acid","kind":"drug","name":"Aminolevulinic acid (topical, for photodynamic therapy)","route":"/drugs/aminolevulinic-acid/"},{"id":"fluorouracil","kind":"drug","name":"Fluorouracil (5-FU)","route":"/drugs/fluorouracil/"},{"id":"imiquimod","kind":"drug","name":"Imiquimod","route":"/drugs/imiquimod/"}],"pathway":[{"id":"field-cancerisation","kind":"pathway","name":"Field cancerisation","route":"/pathways/field-cancerisation/"}]}}