Basal cell carcinoma



Basal cell carcinoma


James M. Spencer and Brooke M. Walls


Evidence Levels:  A Double-blind study  B Clinical trial ≥ 20 subjects  C Clinical trial < 20 subjects  D Series ≥ 5 subjects  E Anecdotal case reports


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Basal cell carcinoma (BCC) is a slow-growing malignancy originating in the epidermis. It most commonly arises in areas chronically exposed to UV light, especially the head and neck. Although it is very rare for BCC to metastasize, it can produce significant local tissue destruction, including cartilage and bony invasion.



Management strategy


Basal cell carcinoma slowly but relentlessly grows larger and deeper, and therefore therapeutic intervention is geared towards complete eradication of all malignant cells. Local recurrence is the consequence of inadequate therapy. Complete eradication is especially important because recurrent tumors are often larger and more aggressive than the original, incompletely treated primary tumor. Although complete eradication is the primary goal, the therapy chosen should achieve this with the maximal preservation of function and the optimal cosmetic result. Most often, therapy uses destructive techniques such as cryotherapy or curettage and electrodesiccation (C&D); more complex tumors may be treated by excisional surgery, Mohs surgery, or radiation therapy. The decision about which therapy to use is best made by considering four factors: tumor size; location; histology; and history (recurrent vs primary). When assessing a tumor, the clinician may wish to consider each of these four factors and decide whether the patient is high risk or low risk for each, to determine whether to use a simple or complex therapeutic strategy.


Most BCCs are discovered as primary tumors when they are still less than 1 cm in diameter. Generally tumors smaller than 1 cm on the face and 2 cm on the body are low risk.


Histologic growth pattern is a separate risk factor. The cytology of BCC does not vary: that is, all BCCs have well-differentiated, relatively monomorphic cell populations, and these tumors are not graded the way other malignancies are. However, the pattern of growth is variable and makes a large difference in choosing therapy. One must consider whether the tumor has a circumscribed or a diffuse growth pattern. Basal cell carcinoma most typically exhibits a circumscribed, cohesive growth pattern known as nodular. Nodular BCCs may show partial differentiation towards other structures, such as cystic or keratotic, but these variants are without therapeutic significance because the growth pattern is still nodular. Morpheaform, micronodular, infiltrating and superficial BCCs are all variants that exhibit a diffuse growth pattern. These lesions are more likely to recur as a result of subclinical extension or more aggressive tumor behavior, or both. Unfortunately, all too often biopsy reports come back to the clinician and simply state ‘BCC’, with no information about the growth pattern. Inadequately treated nodular BCC often recurs with a more aggressive diffuse growth pattern, such as infiltrating or micronodular.


Location is also an important variable to consider when choosing which therapy to use. Basal cell carcinoma tends to occur in chronically sun-exposed sites, especially the head and neck. Approximately 80% occur on the head and neck, and fully 25% occur on the nose. The central portion of the face, which has the highest incidence of BCC, contains the eyes, nose, and mouth, structures of functional and cosmetic importance highly vulnerable to the destructive effects of BCC. These same structures are also highly vulnerable to the destructive effects of therapy directed against BCC. The center of the face extending onto the area around the ears defines a roughly H-shaped area known as the H zone. Tumors in this zone have the highest recurrence rate and thus deserve special therapeutic attention. This zone also contains the most vulnerable structures and has the highest rate of BCC occurrence. Tumors near the ear canal, in the H zone, are of special concern. Extension down the ear canal provides the tumor with access to the brain and other intracranial structures, and when there is evidence of ear canal invasion particularly aggressive therapy is warranted.


Lastly, tumor history is important to consider. Recurrent tumors are more difficult to treat than primary tumors and require more aggressive methods.


When confronted with a BCC, the clinician may wish to consider these four variables in the context of the individual patient. The patient’s overall medical status, medical history, and age may influence the therapeutic decision making.



Specific investigations






An adequate biopsy is critical in assessing the tumor. The tumor growth pattern is important information that is impossible to determine if only a superficial fragment is submitted to the laboratory. Deep shave, punch, incisional or excisional biopsy can all give sufficient dermis for such an evaluation. Because metastasis is so rare, no further evaluation is warranted.


A number of non-invasive imaging technologies are being investigated to delineate tumor depth and extent preoperatively and thus guide treatment. These include confocal microscopy, infrared spectroscopy, and ultrasound, but these all remain experimental and are not part of routine care.


Rarely, a BCC may have been neglected and reached a size such that direct bony invasion has occurred. If this is strongly suspected, a preoperative CT scan should be considered.


The possibility that patients with a BCC have an increased risk of developing subsequent internal malignancies has been suggested over the years, and remains controversial. At present there is no recommendation for extraordinary evaluation for internal malignancies beyond routine medical care in patients with a history of BCC.







Basal cell carcinoma and risk of subsequent malignancies: a cancer registry-based study in southwest England.

Bower CP, Lear JT, Bygrave S, Etherington D, Harvey I, Archer CB. J Am Acad Dermatol 2000; 42: 988–91.


A cohort of 13 961 patients diagnosed with BCC between 1981 and 1988 were followed for additional malignancies. There was a significant increased risk of subsequent melanoma, but no increased risk for internal malignancies.


Further complicating the relationship of BCC to other cancers is the argument that vitamin D provides chemoprevention for some visceral cancers. Specifically, it has been theorized that elevated levels of vitamin D lower the incidence of a variety of tumors, including breast, colon, and prostate cancers. As vitamin D is manufactured in the skin following exposure to UVB, it has been suggested that those with high UVB exposure should have a higher incidence of BCC but a lower incidence of breast, colon, and prostate cancers, among others.




First-Line therapies


















imageCurettage and electrodesiccation B
imageCryosurgery B
imageExcisional surgery B
imageMohs micrographic surgery B








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Aug 7, 2016 | Posted by in Dermatology | Comments Off on Basal cell carcinoma

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