Cutaneous squamous cell carcinoma (cSCC) is the second most common form of skin cancer in united states, known for its potential to invade local tissues and metastasize if untreated. This blog post aims to provide a detailed examination of squamous cell carcinoma of the skin, focusing on its risk factors, clinical presentation, diagnosis, and management strategies.
Table of Contents
- Risk Factors of Cutaneous Squamous Cell Carcinoma
- Signs and Symptoms
- Diagnosis
- Treatment of Cutaneous Squamous Cell Carcinoma
- Complications of Squamous Cell Carcinoma of the skin
- Key Differences Between Squamous Cell Carcinoma (SCC) and Basal Cell Carcinoma (BCC)
Risk Factors of Cutaneous Squamous Cell Carcinoma
- Ultraviolet (UV) Radiation: Chronic exposure to UV-A and UV-B radiation is the leading cause of cSCC. Patients with a history of prolonged sun exposure, tanning beds, or sunburns are at higher risk.
- Environmental Exposures: Chronic exposure to environmental carcinogens (Arsenic, ionizing radiation, and certain chemicals like polycyclic aromatic hydrocarbons)
- Demographics: Fair-skinned individuals, particularly males and the elderly, are more likely to develop cSCC.
- Immunosuppression: Patients with organ transplants, leukemia, or HIV/AIDS
- Genetic Syndromes: Xeroderma pigmentosum, oculocutaneous albinism, and epidermodysplasia verruciformis
- Preexisting Skin Lesions: Chronic wounds, actinic keratosis, and human papillomavirus (HPV) infections.
Signs and Symptoms
Squamous cell skin cancer symptoms can vary depending on the lesion’s size, location, and depth of invasion. Commonly, cSCC appears as a scaly, erythematous, or hyper-pigmented papule or plaque. They often found on sun-exposed areas such as the face, ears, neck, or hands.
Other presentations may include:
- A new sore or lesion that does not heal
- A wart-like growth
- A rough, scaly patch that bleeds easily
- Persistent pain or discomfort at the lesion site
If the carcinoma invades deeper layers, it may lead to ulceration, extensive local tissue destruction, and, in rare cases, metastasis to lymph nodes or distant organs
Diagnosis
A definitive diagnosis of cutaneous squamous cell carcinoma (cSCC) requires a skin biopsy. In advanced cases, more diagnostic modalities are needed. Sentinel lymph node biopsy and/or imaging studies like computed tomography (CT) or ultrasound to assess for lymph node metastasis.
For patients presenting with palpable lymph nodes, fine-needle aspiration or biopsy of the lymph nodes is advised to rule out or confirm metastasis.
Treatment of Cutaneous Squamous Cell Carcinoma
The gold standard for treating squamous cell carcinoma skin cancer is surgical excision, with Mohs micrographic surgery being the preferred option for high-risk or cosmetically sensitive cases. Factors that make a patient a candidate for Mohs surgery include lesion diameter greater than 2 cm, high-risk histological features, recurrent lesions, or lesions located in high-risk anatomical areas like the ears, lips, nose, or around the eyes. Mohs surgery has a 5-year recurrence rate of approximately 3.1%, compared to 8.1% for standard excision.
Electrodessication and curettage may be considered for in situ lesions, though these treatments have higher recurrence rates compared to Mohs surgery or standard excision.
For patients who are not surgical candidates, alternative treatments include:
- Superficial radiation therapy
- 5-fluorouracil cream
- Imiquimod cream
- Cryotherapy
- Photodynamic therapy
- Ablative laser therapy
Complications of Squamous Cell Carcinoma of the skin
Untreated squamous cell carcinoma (SCC) can lead to local invasion and destruction of nearby tissues, resulting in significant functional impairment and poor cosmesis. Unlike basal cell carcinoma, SCC has a higher potential for metastasis to regional lymph nodes and distant organs such as the lungs, liver, or brain. If left untreated, this can lead to severe complications and poor prognosis, underscoring the importance of early diagnosis and treatment to prevent both physical disfigurement and life-threatening metastasis.
Key Differences Between Squamous Cell Carcinoma (SCC) and Basal Cell Carcinoma (BCC)
Both squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) are common forms of non-melanoma skin cancers, but they differ in origin, behavior, and clinical presentation.
| Squamous Cell Carcinoma (SCC) | Basal Cell Carcinoma (BCC) | |
| Origin | Arises from keratinocytes, the cells in the outermost layer of the epidermis (stratum spinosum). | Arises from basal cells located in the lower part of the epidermis. |
| Appearance | Appears as scaly, red patches, open sores, or rough, thickened skin, often with a central ulceration. Can bleed or crust over. | Appears as a pearly, flesh-colored bump, or a flat, pink/red patch. May have visible blood vessels (telangiectasia) and may ulcerate. |
| Metastasis | More likely to invade deeper tissues and has a higher chance of metastasis to lymph nodes or distant organs. | Locally invasive but rarely metastasises (Some books says it never metastasis). It grows slowly but can cause significant local damage if untreated. |
| Histology | Keratine pearls can be seen | In well differentiated cancer, histology shows features similar to basal cell of the epidermis. |
