From the Guidelines
Basal cell carcinomas (BCCs) do not typically light up differently under standard UV light. Unlike some other skin conditions that may fluoresce under Wood's lamp examination (a specialized UV light source), BCCs generally do not exhibit characteristic fluorescence patterns that would aid in diagnosis 1. Dermatologists primarily rely on visual examination, dermoscopy, and biopsy for BCC diagnosis rather than UV light examination. However, newer advanced imaging technologies like fluorescence confocal microscopy and photodynamic diagnosis using specific photosensitizing agents can sometimes highlight BCCs, but these are specialized techniques not commonly used in routine clinical practice. The lack of distinctive UV fluorescence occurs because BCCs don't naturally contain substances that significantly fluoresce under UV wavelengths. For skin cancer detection, dermatologists typically use dermoscopy, which uses polarized light rather than UV light, to examine suspicious lesions for characteristic features of BCCs such as arborizing vessels, blue-gray ovoid nests, and ulceration.
Some key points to consider in the diagnosis of BCCs include:
- The use of good lighting and magnification, and the dermatoscope may be helpful in some cases 1
- Biopsy is indicated when clinical doubt exists or when patients are being referred for a subspecialty opinion, when the histological subtype of BCC may influence treatment selection and prognosis 1
- Imaging techniques such as computed tomography or magnetic resonance imaging may also be utilized 1
- Topical photodynamic therapy (PDT) has been approved for use in certain nonmelanoma skin cancer indications, including superficial and nodular BCCs 1
It's worth noting that while UV light examination is not typically used for BCC diagnosis, photodynamic diagnosis using specific photosensitizing agents can sometimes highlight BCCs 1. However, these techniques are not commonly used in routine clinical practice. The most recent and highest quality study on this topic is from 2019, which provides guidelines for topical photodynamic therapy in nonmelanoma skin cancers and precancerous lesions 1.
From the Research
Basal Cell Carcinoma and UV Light
- Basal cell carcinoma (BCC) is the most common malignant skin cancer, and its development is strongly linked to UV radiation exposure 2, 3.
- UV radiation, particularly short-wavelength UVB radiation, damages DNA and its repair system, leading to genetic alterations and the formation of neoplasms 2.
- The use of UV light in diagnosing BCC is not explicitly mentioned in the provided studies, but dermoscopy, which can utilize UV light, is used to monitor treatment response and assess residual disease after incomplete surgical excision 4.
- There is no direct evidence in the provided studies to suggest that basal cell carcinoma lights differently under UV light, but UV radiation is a key factor in its development and progression 2, 3, 5.
Risk Factors and Treatment
- Risk factors for BCC development include sun exposure, family history of skin cancers, skin type 1 and 2, immunosuppression, and chronic exposure to toxic substances 2, 5.
- Treatment options for BCC include surgical excision, topical therapies such as imiquimod, and other modalities selected based on recurrence risk, tissue preservation, and patient preference 4, 6, 5.
- Imiquimod has been shown to be an effective adjuvant therapy for incompletely excised BCC, promoting a Th-1 immune response and enhancing the removal of neoplastic cells 4, 6.