Merkel cells themselves are specialized cells located in the lower part of the epidermis and are thought to function as touch receptors with neuroendocrine properties. They are not visible to the naked eye but are microscopic cells involved in sensory functions

. When Merkel cells become cancerous, they form Merkel cell carcinoma (MCC), which appears on the skin as a firm, painless bump or nodule. The typical appearance of Merkel cell carcinoma includes:

• A single, firm, dome-shaped or raised lump
• Color can range from pink, red, purple to skin-colored or bluish-red
• The surface is often smooth but can sometimes be scaly or ulcerated (broken skin)
• The lesion grows rapidly over weeks
• It is usually painless
• Can be mistaken for other skin conditions like cysts, warts, pimples, insect bites, or styes
• Often found on sun-exposed areas such as the face, neck, arms, legs, and eyelids
• Nearby lymph nodes may be enlarged if the cancer has spread

Clinically, MCC lesions may look like shiny or pearly nodules or bumps that can be red, violet, or skin-colored. They may resemble warts or cysts but tend to have visible enlarged blood vessels and grow quickly

. In summary, Merkel cell carcinoma looks like a fast-growing, firm, painless, dome-shaped lump on sun-exposed skin, often red or purple in color, sometimes mistaken for benign skin lesions. The only definitive way to identify MCC is through biopsy and microscopic examination