The question of whether skin cancer can develop on the buttocks, an area almost always shielded from the sun, is a common and important one. While the majority of cases are strongly associated with ultraviolet (UV) radiation exposure, the disease is not exclusively a condition of sun-damaged skin. The cellular processes that lead to malignancy can be triggered by factors beyond sunlight. Skin cancer can appear anywhere on the body, including in regions that are rarely or never exposed to the sun.
Skin Cancer in Non-Sun Exposed Areas
Skin cancer can occur in areas that see no direct sunlight because the underlying causes are not limited to UV-induced DNA damage. One significant factor is a person’s genetic makeup, which can predispose them to cancer regardless of sun exposure. Inherited conditions, such as xeroderma pigmentosum, impair the skin’s ability to repair DNA damage, making individuals much more susceptible to malignancies even on covered skin. A family history of melanoma, basal cell carcinoma, or squamous cell carcinoma increases the overall risk of developing the disease anywhere on the body.
Another mechanism involves chronic inflammation or persistent injury to the skin, which can trigger cancer-causing mutations through a distinct biological pathway. The repeated cycle of damage and repair creates an inflammatory microenvironment that promotes the transformation of normal cells into malignant ones. Exposure to certain harmful chemicals or prolonged radiation, even from medical treatments, also acts as an environmental trigger for abnormal cell growth in shielded areas. These non-UV related mechanisms provide the biological explanation for why the buttocks, along with the palms of the hands or soles of the feet, remain susceptible to developing skin cancer.
Types of Skin Cancer Found on the Buttocks
The three primary forms of skin cancer—melanoma, basal cell carcinoma (BCC), and squamous cell carcinoma (SCC)—have all been documented to appear on the buttocks.
Melanoma
Melanoma, the most serious form, develops from the pigment-producing cells called melanocytes, which are present throughout the skin. Melanoma occurring in non-sun-exposed regions is often detected at a later stage, which can contribute to a more serious prognosis. When found on the buttocks, melanoma may present as a dark spot or an irregular patch that looks different from other moles on the body.
Squamous Cell Carcinoma (SCC)
SCC, which arises from the skin’s flat, surface cells, is the second most common type of skin cancer. While typically associated with sun exposure, SCC can also develop in areas of chronic inflammation, scarring, or on skin that has been exposed to chemical agents. On the buttocks, SCC may look like a persistent, scaly, reddish patch with irregular borders that might bleed or crust. It can also appear as a firm, red nodule that feels rough to the touch.
Basal Cell Carcinoma (BCC)
BCC, the most common type of skin cancer overall, is rare on the buttocks but does occur. BCC in this location frequently presents as an asymptomatic nodule, meaning it does not cause pain or irritation. This presentation is typically associated with a non-aggressive subtype of BCC, and most patients do not have the traditional risk factors connected to sun exposure. BCCs in concealed areas may also appear as a pearly, flesh-colored bump or a scar-like lesion that may be white or waxy.
Recognizing Unusual Skin Changes
Vigilance and self-examination are the most practical measures for detecting skin cancer in areas that are difficult to see. Routine self-checks should involve using a hand mirror or asking a partner to examine the buttocks, perineal area, and any skin folds. The key is to look for any new growths or changes in existing moles or spots that persist over several weeks.
For suspicious pigmented lesions, the widely used ABCDE rule for melanoma detection is the best guide, even for non-sun-exposed skin. This rule assesses a spot for five key characteristics:
- Asymmetry
- Irregular Border
- Multiple Colors
- Diameter larger than a pencil eraser (6mm)
- Evolution (any change in size, shape, or color over time)
A different method, known as the “Ugly Duckling” sign, involves identifying any mole that stands out or looks distinctly different from the surrounding spots. Any lesion that bleeds, crusts, or fails to heal over several weeks requires immediate professional evaluation, regardless of its location. Individuals with a high-risk profile, such as those with a family history of skin cancer or numerous moles, should prioritize annual full-body skin exams with a dermatologist. Early diagnosis is a significant factor in successful treatment for all types of skin cancer.