- Clinical science
Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer after basal cell carcinoma. It occurs as a result of malignant transformation of keratinocytes in the stratum spinosum (prickle cell layer) of the epidermis. Risk factors for malignant transformation include exposure to sunlight, chemical carcinogens, precancerous lesions of the skin (e.g., actinic keratosis), and sites of skin damage (e.g., scars, burns, ulcers). Although the classic clinical presentation is a painless, non-healing, bleeding ulcer with everted edges, cSCC may initially present as plaques, nodules, or even warty lesions. All suspicious skin lesions should be biopsied to confirm the diagnosis, determine the histological grade and stage the tumor. Further evaluation (e.g., imaging, lymph node biopsies) may be required in cases with high-risk features to rule out regional and/or systemic metastasis. The treatment of choice is surgical excision of the lesion with a wide safety margin. Moh's micrographic surgery, which is associated with lower rates of tumor recurrence and better cosmetic results, is increasingly used instead of standard surgical excision. Radiotherapy and/or chemotherapy may be used as adjuvants in cases with high-risk features.
- Second most common form of skin cancer after basal cell carcinoma
- Sex: ♂ > ♀ (2:1)
- Incidence: increases with age
- Greater incidence near the equator and among whites
Epidemiological data refers to the US, unless otherwise specified.
- Malignant transformation of keratinocytes in the stratum spinosum (prickle cell layer) of the epidermis.
- Risk factors:
- Sun exposure; (especially among fair-skinned individuals)
- Exposure to ionizing radiation
- Exposure to chemical carcinogens (e.g., coal tars through smoking, arsenic)
- Areas of chronically damaged skin (see below)
- Chronic immunosuppression (e.g., HIV, transplant patients who receive immunosuppressive therapy)
- ; (especially ; and )
- Most commonly on the face and neck
- A typical location is the lower lip.
- Growth and spread
The classic clinical presentation of cSCC is a painless, non-healing, bleeding ulcer.
Biopsy: should extend into the midreticular dermis for suspicious lesions
- Further evaluation may be indicated in cases with high-risk features to look for regional and/or systemic metastasis.
- Imaging (e.g., CT, MRI)
- Lymph node biopsies, FNAC
A biopsy should be performed on any suspicious skin lesion!
Broder's histological grading
- Grade 1 (highly differentiated): > 75% of keratinocytes are well differentiated
- Grade 2 (moderately differentiated): 50–75% of keratinocytes are well differentiated
- Grade 3 (poorly differentiated): 25–50% of keratinocytes are well differentiated
- Grade 4 (undifferentiated/anaplastic): < 25% of keratinocytes are well differentiated
Definition: low-grade tumor , more common in the elderly
- Associated with
- Characteristic features
- Treatment: : The tumor usually heals without treatment; . Nonetheless, surgical removal is preferred because keratoacanthoma histologically resembles a cSCC, which is malignant.
- Definition: low-grade tumor , more common in the elderly
- ; ,
The differential diagnoses listed here are not exhaustive.
Surgical excision of the lesion along with a rim of normal skin is the primary method of treatment.
- Cryotherapy or curettage with electrodesiccation may be used in case of carcinoma-in-situ; its use is contraindicated in case of invasive cSCC.
- Moh's micrographic surgery is increasingly used in place of standard surgical excision.
- Adjuvant treatment in cases with high-risk features
- Primary treatment when tumors are inoperable (e.g., patient is unfit for surgery).
Chemotherapy (e.g., 5-fluorouracil, epidermal growth factor inhibitors)
- Indicated in case of systemic metastasis
- Adjuvant treatment in cases with high-risk features.