Basal cell carcinoma

Last updated: November 29, 2023

Summarytoggle arrow icon

Basal cell carcinoma (BCC) is a keratinocyte cancer and the most common type of skin cancer overall. BCC is caused by genetic mutations within the sonic hedgehog signaling (SHH) pathway affecting the basal keratinocytes, hair follicles, and eccrine sweat glands. Important risk factors include UV exposure and a history of organ transplantation. Some individuals have a genetic predisposition to BCC. BCC typically occurs in individuals > 40 years of age and lesions are commonly seen on sun-exposed areas (e.g., head and neck). Typical characteristics include a nonhealing, slow-growing nodule or plaque that may bleed easily or ulcerate. Dermoscopy can be used to support clinical findings, but a skin biopsy is necessary for diagnostic confirmation. Nodular BCC and superficial BCC are the most common histologic subtypes. Risk stratification of BCC is used to classify the lesions as low-risk or high-risk for recurrence after excision and thereby guide management. Tumor resection (Mohs micrographic surgery or surgical excision) is the preferred treatment modality; radiotherapy can be considered if resection is not feasible. Other treatment modalities (e.g., cryotherapy, topical pharmacotherapy, photodynamic therapy) may be considered in selected situations but are associated with higher recurrence rates than resection. Metastatic BCC is rare but has a poor prognosis; multidisciplinary care is recommended. All patients should be screened for recurrence and the development of new skin cancers after treatment. Photoprotective measures should be recommended to all individuals for primary prevention and the prevention of recurrent or subsequent skin cancers.

Risk factorstoggle arrow icon

The use of a tanning bed before 24 years of age doubles the risk of developing BCC. [2]

Epidemiologytoggle arrow icon

Epidemiological data refers to the US, unless otherwise specified.

Clinical featurestoggle arrow icon

Most basal cell carcinomas occur on areas of sun-exposed skin. [1][2]

Subtypes and variantstoggle arrow icon

There are several clinical and histological BCC variants; the most common are described here.

BCC lesions may have more than one clinical and histopathological subtype. [1][2]

Low-risk BCC subtypes [1][2]

Nodular basal cell carcinoma

The most frequently occurring subtype of BCC (accounts for 50–80% of BCC) [1][2]

Superficial basal cell carcinoma

The second most frequent subtype of BCC (accounts for 10–30% of BCC) [1][2]

  • Plaque with the following:
    • Thin and scaly
    • Raised border with a pearl-like appearance
    • Central atrophy
  • Most commonly located on the trunk and legs

Superficial BCC is the least invasive BCC subtype. [2]

Pigmented basal cell carcinoma [1][2]

Features of pigmented basal cell carcinoma can resemble those of melanoma. [1][2]

High-risk BCC subtypes [1][2][3]

These lesions account for < 20% of all BCCs.

  • Micronodular: erythematous macule, thin papule, or plaque
  • Infiltrative
    • Poorly defined flat or depressed light-colored papule or plaque with the following:
    • Other features include induration, ulceration, and crust formation
  • Morpheaform
    • Poorly defined, shiny plaque
    • Can resemble a scar
    • Aggressive; high risk of local recurrence after excision
  • Other: basosquamous (metatypical), sclerosing

Micronodular and infiltrative BCC may be clinically indistinguishable from superficial or nodular BCC. Histopathological examination is needed to confirm the diagnosis. [2]

Nevoid basal-cell carcinoma syndrome (Gorlin syndrome) [1][7]

Diagnosticstoggle arrow icon

General principles [3][4]

Dermoscopy findings of BCC [9][10]

  • Arborizing (branching) blood vessels
  • Ulceration
  • Crystalline structures (i.e., shiny white areas or streaks)
  • Pigmented features of BCC
    • Large blue-gray ovoid nests
    • Leaf-like structures
    • Multiple blue-gray nonaggregated globules
    • Spoke wheel-like concentric structures

Skin biopsy [2][4]

Select a biopsy technique based on the clinical features of the lesion and procedural risks ; use shared-decision making.

  • Techniques:
  • Ensure adequate sample size and depth (including the deep reticular dermis) for histopathological examination; if not, a repeat biopsy may be required. [3][4]
  • To optimize the quality of the pathology report, biopsy samples should include the following: [4]
    • Patient demographics
    • Presence of risk factors for BCC
    • Size and morphology of the lesion
    • Initial sample or repeat

Perform a full-thickness excisional biopsy if there is any concern for malignant melanoma (e.g., pigmentation, ABCDE criteria). [2]

Pathologytoggle arrow icon


Differential diagnosestoggle arrow icon

Other common skin cancers or precancerous lesions [2]

Benign skin conditions [2]

Trichoepithelioma [12]

The differential diagnoses listed here are not exhaustive.

Stagingtoggle arrow icon

Assessment of disease extent [3]

Refer patients with high-risk features of BCC to a specialist (e.g., oncologist) for diagnostic evaluation for locoregional, nodal, and distant metastases, which may include:

Imaging for staging is rarely required because metastasis is uncommon. If perineural metastasis is suspected, MRI is the preferred imaging modality. [3]

Staging [2][4]

  • BCC is a locally invasive tumor that rarely metastasizes.
  • Staging using the AJCC TNM staging system has limited clinical utility; can be used to stage metastatic disease.
  • Stratifying BCC based on the risk of recurrence after excision is recommended to guide clinical decision-making.

Risk stratification of BCC [2][3][4]

Risk stratification is based on clinical and histopathological features.

High-risk features of BCC [1][3][4]
Tumor characteristics
  • ≥ 2 cm in size and located on the trunk or extremities
  • BCC of any size located in the following areas:
    • Head and neck
    • Pretibial region
    • Hands or feet
    • Anogenital region
  • Poorly defined borders
  • Recurrent lesion
Histopathology features
Patient factors

Treatmenttoggle arrow icon

General principles [2][3][4]

Overview of treatment options [2][3][4]

Overview of treatment options for BCC [2][3][4]
Indications Special considerations
Mohs micrographic
surgery (MMS)
  • Recommended for high-risk BCC
  • Preferred if minimal tissue excision is required.
  • Consider for management of positive margins after surgical excision.
  • Lowest recurrence rate of all treatment options
  • Limited availability; hence reserved for high-risk, recurrent, or complex lesions
Surgical excision
Curettage and
electrodessiccation (C&E)
  • Histologic margin assessment is not feasible.
  • Contraindicated for tumors:
    • On cosmetically sensitive areas
    • On hair-bearing skin
    • Extending beyond the dermis
  • Convert to surgical excision if the subcutaneous layer is breached.
Shave removal
  • Suture closure is not required.
  • Complete margin assessment is not performed
  • Convert to surgical excision if the subcutaneous layer is breached.
Radiotherapy (RT)
  • Primary RT: Consider when resection is not feasible.
  • Consider adjuvant RT for:
    • BCC with perineural involvement
    • Management of positive margins after resection
  • Requires multiple sessions
  • Typically used for adults > 60 years of age
  • Contraindicated in individuals with a genetic predisposition for skin cancers.
topical pharmacotherapy,
and/or photodynamic therapy
  • Higher risk of recurrence than surgery or RT
  • Topical pharmacotherapy
    • Agents: imiquimod (preferred) and 5-FU
    • Requires multiple sessions
    • Adverse effects: skin irritation and inflammation
  • Histological margin assessment is not feasible.
Systemic therapies
  • Locally advanced or metastatic BCC that is not amenable to resection or curative RT
  • Can be used for primary or recurrent BCC lesions
  • Includes:

MMS is considered superior to surgical excision, as the entire tumor margin is intraoperatively assessed to ensure R0 resection, which reduces the risk of recurrence, and the conservation of healthy tissue is maximized. [3][4]

BCC typically extends beyond the clinically visible margins. Incompletely excised tumors have a recurrence rate of ∼ 26% compared to ∼ 6% after R0 resection. [4]

Localized BCC [2][3][4]

High-risk BCC

  • Preferred: MMS
  • Alternatives
    • Surgical excision with wide margins
    • RT for patients who cannot undergo resection
  • Consider adjuvant RT if there is evidence of perineural or large nerve invasion.

Low-risk BCC

Avoid electrodesiccation and curettage in lesions in cosmetically sensitive areas (e.g., face) and hair-bearing areas. [3][4]

Locally advanced or metastatic BCC [2][3][4]

Specialist referral and multidisciplinary care are recommended to consider the following options:

Follow-up for BCC [3][4]

Regular follow-up is essential as patients are at an increased of developing subsequent skin cancers. [3]

  • Screen for skin cancers every 6–12 months for 5 years; then annually for life.
  • Encourage adherence to photoprotective measures.
  • Educate patients and/or caregivers on self-examination to detect recurrence or new lesions.

Follow-up with a dermatologist is strongly recommended for immunosuppressed individuals and those with ≥ 4 nonmelanoma skin cancers and/or ≥ 1 melanoma in the past 5 years. [3]

Prognosistoggle arrow icon

  • Excellent prognosis with a low rate of metastasis (< 0.1%) [3]
  • If metastasis occurs, the prognosis is poor. [4]
  • Individuals with a history of BCC are at an increased risk of developing subsequent BCC and other skin cancers (SCC, melanoma). [2][3]

Preventiontoggle arrow icon

  • Screening: Consider recommending regular skin self-examination (e.g., monthly). [14][15]
  • Prevention: Recommend photoprotective measures to all individuals regardless of skin type. [14][16]

Related One-Minute Telegramtoggle arrow icon

Referencestoggle arrow icon

  1. Cameron MC, Lee E, Hibler BP, et al. Basal cell carcinoma. J Am Acad Dermatol. 2019; 80 (2): p.303-317.doi: 10.1016/j.jaad.2018.03.060 . | Open in Read by QxMD
  2. Firnhaber JM. Basal Cell and Cutaneous Squamous Cell Carcinomas: Diagnosis and Treatment. Am Fam Physician. 2020; 102 (6): p.339-346.
  3. Schmults CD, Blitzblau R, Aasi SZ, et al. Basal Cell Skin Cancer, Version 2.2024, NCCN Clinical Practice Guidelines in Oncology. JNCCN. 2023; 21 (11): p.1181-1203.doi: 10.6004/jnccn.2023.0056 . | Open in Read by QxMD
  4. Kim JYS, Kozlow JH, Mittal B, et al. Guidelines of care for the management of basal cell carcinoma. J Am Acad Dermatol. 2018; 78 (3): p.540-559.doi: 10.1016/j.jaad.2017.10.006 . | Open in Read by QxMD
  5. Bae JM, Ju HJ, Lee RW, et al. Evaluation for Skin Cancer and Precancer in Patients With Vitiligo Treated With Long-term Narrowband UV-B Phototherapy. JAMA Dermatol.. 2020; 156 (5): p.529.doi: 10.1001/jamadermatol.2020.0218 . | Open in Read by QxMD
  6. Dinnes J, Deeks JJ, Chuchu N, et al. Visual inspection and dermoscopy, alone or in combination, for diagnosing keratinocyte skin cancers in adults. Cochrane Database Syst Rev. 2018; 2018 (12).doi: 10.1002/14651858.cd011901.pub2 . | Open in Read by QxMD
  7. Marghoob AA, Usatine RP, Jaimes N. Dermoscopy for the family physician. Am Fam Physician. 2013; 88 (7): p.441-50.
  8. Mayeaux EJ. The Essential Guide to Primary Care Procedures. LWW ; 2015
  9. Grossman DC, Curry SJ, et al. Behavioral Counseling to Prevent Skin Cancer. JAMA. 2018; 319 (11): p.1134.doi: 10.1001/jama.2018.1623 . | Open in Read by QxMD
  10. Bibbins-Domingo K, Grossman DC, et al. Screening for Skin Cancer. JAMA. 2016; 316 (4): p.429.doi: 10.1001/jama.2016.8465 . | Open in Read by QxMD
  11. Sánchez G, Nova J, Rodriguez-Hernandez AE, et al. Sun protection for preventing basal cell and squamous cell skin cancers. Cochrane Database Syst Rev. 2016; 2016 (9).doi: 10.1002/14651858.cd011161.pub2 . | Open in Read by QxMD
  12. James WD, Berger T, Elston D. Andrews' Diseases of the Skin: Clinical Dermatology. Elsevier Health Sciences ; 2015
  13. Bresler SC, Padwa BL, Granter SR. Nevoid Basal Cell Carcinoma Syndrome (Gorlin Syndrome). Head Neck Pathol. 2016; 10 (2): p.119-124.doi: 10.1007/s12105-016-0706-9 . | Open in Read by QxMD
  14. John Y.S. Kim, Et al. Guidelines of care for the management of cutaneous squamous cell carcinoma. J Am Acad Dermatol. 2018; 78 (3): p.560-578.doi: 10.1016/j.jaad.2017.10.007 . | Open in Read by QxMD
  15. Marks JG Jr, Miller JJ . Lookingbill and Marks' Principles of Dermatology. Saunders Elsevier ; 2013
  16. Rahman J, Tahir M, Arekemase H, Murtazaliev S, Sonawane S. Desmoplastic Trichoepithelioma: Histopathologic and Immunohistochemical Criteria for Differentiation of a Rare Benign Hair Follicle Tumor From Other Cutaneous Adnexal Tumors. Cureus. 2020; 12 (8): p.e9703.doi: 10.7759/cureus.9703 . | Open in Read by QxMD

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