Skin cancer can form on the buttocks. The idea that skin cancer only affects sun-exposed areas is a common misconception. While ultraviolet radiation is a primary cause globally, the disease is fundamentally a mutation of skin cells that exist across the entire body, regardless of sun exposure. Understanding this reality is the first step in comprehensive skin health awareness, particularly for parts of the body often overlooked during routine self-examinations.
Yes, Skin Cancer Can Occur Anywhere
Skin cancer results from the uncontrolled growth of abnormal cells in the epidermis. This cellular malfunction can be triggered by UV light, but it is not exclusively dependent on it. Pigment-producing and structural cells are distributed everywhere, meaning any patch of skin is susceptible to cancerous changes.
Skin areas like the buttocks, groin, palms, and under the nails are typically protected from daily sunlight. However, they remain vulnerable to non-UV related causes of cell mutation. Cancers arising in these hidden locations are often detected at a later stage because they are not routinely seen or checked. This delayed diagnosis emphasizes the importance of awareness for improving treatment outcomes.
Skin Cancers That Develop Without Sun Exposure
Melanoma, the most aggressive form of skin cancer, is a significant concern in non-sun-exposed regions. It arises from melanocytes, the pigment-producing cells that exist throughout the skin. While many melanomas are linked to sun damage, some subtypes are not, allowing them to appear anywhere.
Acral lentiginous melanoma is one subtype not caused by UV exposure, often appearing on the palms, soles, or under the nails. Amelanotic melanoma also poses a risk because it lacks pigment, appearing pink, red, or skin-colored, making it easy to mistake for a harmless lesion. Squamous Cell Carcinoma (SCC), the second most common form, can develop in areas affected by chronic inflammation, scarring, or injury.
Non-UV related causes, such as genetic predisposition, play a larger role in hidden-site cancers. Chronic irritation, like from pressure sores or chemical exposures, can also cause the cellular damage leading to SCC. Basal Cell Carcinoma (BCC), the most common form, is primarily sun-related but can occasionally appear in less exposed parts of the body.
Identifying Warning Signs in Concealed Skin
Since concealed areas like the buttocks are not part of daily visual checks, self-examination requires a deliberate approach. The standard signs for melanoma, known as the ABCDEs, are still relevant: Asymmetry, irregular Border, varied Color, large Diameter (over 6mm), and Evolving change. In hidden regions, there are also additional specific signs to watch for.
A new growth, especially if dark, or any existing mole changing in size or texture should prompt immediate attention. On the buttocks, a persistent sore that does not heal within two weeks is a significant warning sign for both melanoma and non-melanoma skin cancers. Other concerning features include lesions that bleed without being bumped, or a spot that develops a crust or a scaly surface.
The “ugly duckling” sign is helpful, suggesting that a suspicious spot looks distinctly different from surrounding moles. Because the area is less visible, changes in sensation, such as persistent itching, tenderness, or pain in a specific spot, are also important indicators requiring professional evaluation.
The Importance of Comprehensive Skin Checks
The greatest danger associated with skin cancer in concealed areas is the delay in diagnosis. Since lesions go unnoticed for longer periods, the cancer often has more time to progress before detection. Regular, comprehensive self-examination is necessary for early intervention.
A full-body self-exam should be performed monthly. Use a full-length mirror and a hand mirror to inspect difficult-to-see areas like the backs of the legs, scalp, and buttocks. Enlisting the help of a partner or family member is a practical strategy for thoroughly checking all hidden skin surfaces. Beyond self-checks, professional, annual full-body skin examinations by a dermatologist are recommended.
A dermatologist is trained to spot subtle changes and uses specialized tools to examine suspicious lesions closely. This proactive approach ensures abnormal growths in low-visibility areas are identified while the cancer is in its earliest, most treatable stage. Early detection of melanoma, for instance, is associated with a five-year survival rate of approximately 99%.