27 November 2023
Differentiating Between Actinic Keratosis and Basal Cell Carcinoma: Appearance and Diagnosis
Skin cancer is a prevalent and potentially dangerous condition, with different types requiring unique approaches to diagnosis and treatment. Two common forms of skin cancer are actinic keratosis (AK) and basal cell carcinoma (BCC). While both conditions are related to sun exposure, they have distinct characteristics and treatment options. In this article, we will explore the differences between actinic keratosis and basal cell carcinoma, including their appearance, causes, and available treatments.
How Actinic Keratosis and Basal Cell Carcinoma Look
Actinic keratosis and basal cell carcinoma have distinct visual characteristics that can help differentiate between the two conditions. Actinic keratosis lesions are small, scaly, and rough, often presenting as red, tan, white, pink, or flesh-toned patches on the skin. These lesions can be raised or flat and may feel dry to the touch. On the other hand, basal cell carcinoma often appears as open sores that do not heal for weeks or months, or that reemerge after healing. They may bleed, ooze, or crust, and can also manifest as red, irritated patches of skin that are painful or itchy. Basal cell carcinoma can also present as small, shiny bumps or pink growths with raised, rolled edges and crusted, indented centers. Scar-like areas of skin with poorly defined borders that look shiny or waxy are also indicative of basal cell carcinoma.
Positive Pathology Findings
To definitively diagnose actinic keratosis and basal cell carcinoma, a biopsy is necessary. During a biopsy, a sample of the suspicious lesion is removed for examination in the lab. Pathologists analyze the skin samples under a microscope to check for evidence of cancer. These findings are considered positive for cancer if cancer cells are present. Pathologists can also use the skin samples to rule out other diagnoses, such as benign moles or psoriasis.
Differences and Similarities Between BCC and SCC
Basal cell carcinoma and squamous cell carcinoma (SCC) are the two most common forms of nonmelanoma skin cancer. Both types are primarily caused by long-term sun exposure and affect areas of unprotected skin. Basal cell carcinoma starts in the basal cells of the skin’s outermost layer, while squamous cell carcinoma originates in the squamous cells located in the outer or middle layers of the skin. Basal cell carcinoma is more prevalent, accounting for approximately 75% to 80% of nonmelanoma skin cancer cases, while squamous cell carcinoma accounts for around 20%. Squamous cell carcinoma is faster-growing and more likely to spread into nearby tissues or grow deeply into the skin’s inner layers compared to basal cell carcinoma. However, neither type is likely to metastasize to distant regions of the body.
Actinic Keratosis Progressing to Basal Cell Carcinoma
Actinic keratosis is a precancerous condition that can progress into both squamous cell carcinoma and basal cell carcinoma. However, the progression to squamous cell carcinoma is more common than the progression to basal cell carcinoma. It is believed that the transformation of actinic keratosis into squamous cell carcinoma occurs faster than the progression to basal cell carcinoma, with both transformations potentially taking up to two years.
Sun Exposure: Actinic Keratosis vs. Basal Cell Carcinoma
Long-term sun exposure, especially without protection, is the primary risk factor for both actinic keratosis and basal cell carcinoma. These lesions typically manifest on sun-exposed areas of the body, such as the face. Unprotected exposure to the sun’s ultraviolet (UV) rays, including tanning beds and sunlamps, increases the risk of developing these conditions. Cumulative sun damage over time puts older adults at a higher risk, but anyone of any age can develop skin cancer. Other risk factors include light skin tone, eye color, hair color, susceptibility to sunburns, the presence of many moles, and a family or personal history of skin cancer.
Treatment Differences
The treatment options for actinic keratosis and basal cell carcinoma vary depending on factors such as lesion size, location, and personal health. Actinic keratosis is typically treated more conservatively than basal cell carcinoma. Treatment for actinic keratosis often involves the removal or destruction of the lesion to prevent progression to skin cancer. Cryosurgery, chemical peels, curettage, photodynamic therapy, and laser resurfacing are common treatment options for actinic keratosis. On the other hand, basal cell carcinoma is often treated more aggressively, with surgical removal being a common approach. Mohs surgery, wide-local excision, and curettage with electrodesiccation are surgical procedures used to remove basal cell carcinoma tumors. Other treatment options for basal cell carcinoma include radiation, cryotherapy, topical chemotherapy, photodynamic therapy, immune response modifiers, targeted therapy, and immunotherapy.
Conclusion:
Actinic keratosis and basal cell carcinoma are two distinct forms of skin cancer that share a common link to sun exposure. While actinic keratosis is a precancerous condition that may progress into both squamous cell carcinoma and basal cell carcinoma, the progression to squamous cell carcinoma is more common. Understanding the visual characteristics, causes, and available treatments for these conditions is crucial for early detection and effective management. Regular check-ups with a dermatologist and sun protection measures are essential for maintaining skin health and reducing the risk of skin cancer.
