Core Dermatology Diagnoses / CategoriesNeoplastic Benign and Malignant

Cutaneous squamous cell carcinoma

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Publish date: Posted on
Last updated: March 18, 2021

Keywords #

cutaneous squamous cell carcinoma
skin cancer
keratinocyte carcinoma

Diagnosis #

Squamous cell carcinoma (SCC) is a malignant tumor arising from keratinocytes in the epidermis. It is the second most common skin cancer. Cumulative sun exposure is the greatest risk factor for development of SCC.[1] Other risk factors include immunosuppression, ionizing radiation, chronic inflammation, arsenic exposure, certain medications (e.g., voriconazole, azathioprine, etc.), and inherited conditions (e.g., xeroderma pigmentosum, albinism, etc.). Presumptive diagnosis may be based on history and clinical examination, though histopathologic evaluation is the gold standard and required for diagnosis.

Key Concepts #
  • Squamous cell carcinoma is a malignant tumor arising from keratinocytes.
  • The most common risk factor for developing squamous cell carcinoma is chronic sun exposure.
  • Squamous cell carcinoma classically presents as an erythematous, scaly macule or papule.
  • Histopathologic evaluation is required for the diagnosis of squamous cell carcinoma.
  • Treatment of squamous cell carcinoma involves complete removal or destruction of the primary tumor.
Epidemiology #

SCC is the second most common skin cancer. Lifetime risk of SCC is 9-14% for men and 4-9% for women. Cumulative sun exposure is the greatest risk factor for development of SCC.[1]

Clinical Features #
  • SCC occurs on any cutaneous or mucosal surface, but most commonly occurs on sun-exposed skin.[1,2]
  • The clinical appearance of SCC can be variable ranging from erythematous,scaly macules and papules to ulcerated nodules.
  • Although typically asymptomatic, SCC may bleed, and be pruritic or painful.[2]
Differential Diagnoses #
Diagnostic Workup #

On dermoscopy, squamous cell carcinoma in situ (SCCis) appears with white/yellow surface scale on a red/yellow background color. Invasive SCC may demonstrate white circles and hairpin vessels.[3] However, histopathologic evaluation is required for diagnosis. Shave, punch, or excisional biopsy can be used for tissue sampling. The following variations of squamous cell carcinoma may be diagnosed from histopathologic examination, depending on the extent of the dysplastic tissue.

SCCis/Bowen Disease: Keratinocyte dysplasia involving the full thickness of the epidermis without infiltration of the atypical cells into the dermis.[4] The characteristic histologic feature of the Bowen disease subtype of SCCis reveals numerous mitotic figures, pleomorphic keratinocytes, and acanthosis.

Invasive SCC: Dysplastic keratinocytes involving the full thickness of the epidermis, penetrate the basement membrane, and involve the dermis.[5]

Treatment #

The goal of treatment of SCC is complete destruction or removal of the primary tumor in order to prevent further invasion or metastasis. The appropriate treatment modality depends on the subtype of SCC. SCCis can be treated with more superficial measures such as topical fluorouracil, photodynamic therapy, cryotherapy, or electrodessication and curettage. Invasive SCC should be removed completely via local excision or Mohs micrographic surgery.[6] Radiation therapy can be used as a primary or adjunctive measure following surgical excision to reduce recurrence especially for higher stage tumors such as those with perineural invasion.[6] Radiation therapy as a single modality is typically reserved for patients who are poor surgical candidates. Systemic chemotherapy such as cisplatin, cetuximab, and cemiplimab are usually reserved for metastatic or inoperable tumors. For immunosuppressed patients, such as solid organ transplant recipients, who are at an increased risk of developing SCC, oral retinoids such as acitretin, and niacinamide can be used to decrease the incidence of SCCs.

References #
  1. Alam, M., Armstrong, A., Baum, C., et al (2018). Guidelines of Care for the Management of Cutaneous Squamous Cell Carcinoma. J Am Acad Dermatol, 78(3), 560–578.
  2. Walmad, A., Schmults, C. (2019). Cutaneous Squamous Cell Carcinoma. Hematol Oncol Clin North Am. 33(1):1.
  3. Lim JL, Asgari M. (2020). Cutaneous Squamous Cell Carcinoma (cSCC): Clinical Features and Diagnosis. UpToDate. Retrieved February 10, 2020.
  4. Cassarino DS, Derienzo DP, Barr RJ. Cutaneous squamous cell carcinoma: a comprehensive clinicopathologic classification. Part one. J Cutan Pathol 2006; 33:191.
  5. Cassarino DS, Derienzo DP, Barr RJ. Cutaneous squamous cell carcinoma: a comprehensive clinicopathologic classification–part two. J Cutan Pathol 2006; 33:261.
  6. Stratigos A, Garbe C, Lebbe C, et al. Diagnosis and treatment of invasive squamous cell carcinoma of the skin: European consensus-based interdisciplinary guideline. Eur J Cancer 2015; 51:1989.
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