Nail Unit Squamous Cell Carcinoma

Nail unit squamous cell carcinoma may initially go unnoticed. Any nail can be affected but the thumbnail is most commonly involved. As the tumor progresses, nail unit squamous cell carcinoma can cause changes in the nail plate, nail bed, or surrounding skin, including:

• Changes in Nail Color: Nail unit squamous cell carcinoma may cause discoloration or darkening of the nail plate, including brown, black, or red streaks or bands in the nail plate.
• Changes in Nail Shape: Nail unit squamous cell carcinoma may alter the shape or contour of the nail, causing thickening, cracking, distortion, or irregular growth.
• A wart-like growth: Squamous cell carcinoma of the nail unit can present as a wart-like lesion. Just like cervical cancer or throat cancer, some nail unit squamous cell carcinoma may be caused by the Human Papilloma Virus (HPV). The cancer may present as a wart-like growth underneath the nail (lifting up the nail plate) or along the nail folds.
• Ulceration or Bleeding: Advanced nail unit squamous cell carcinoma may lead to ulceration, crusting, or bleeding around the nail unit.
• Pain or Discomfort: In some cases, nail unit squamous cell carcinoma may cause pain, tenderness, or discomfort in the affected nail or surrounding tissues.

Unlike other forms of squamous cell carcinoma of the skin, nail unit squamous cell carcinoma does not appear to have a close relationship with prolonged or excessive exposure to ultraviolet (UV) radiation from the sun. Nail unit squamous cell carcinoma is more likely to be caused by the human papilloma virus (HPV) than conventional squamous cell carcinoma of the skin.

Several risk factors are known:

• HPV infection: Individuals with prior skin warts or genital warts are at increased risk of nail unit squamous cell carcinoma.
• Tobacco use: Smoking increases the risk of nail unit squamous cell carcinoma.
• Male Gender: Men are more likely than women to develop nail unit squamous cell carcinoma.
• Immunosuppression: Individuals with weakened immune systems, such as organ transplant recipients or those with certain medical conditions, are at higher risk of developing skin cancer, including nail unit squamous cell carcinoma.
• UV Exposure in Nail Cosmetics: The relationship between nail unit squamous cell carcinoma and UV exposure in UV or LED nail lamps used to cure or harden certain nail polishes is unclear but remains an area of research.

The diagnosis of nail unit squamous cell carcinoma is typically made through a combination of medical history, physical examination, and often a skin biopsy. Unlike other types of cancer, you can see skin cancers. This makes early detection easier. Self-examinations at home and skin cancer screening exams in the office help detect skin cancer earlier. If you notice a new growth around or under your nail or a new red or brown discoloration within your nail plate, it is best to check in with a board-certified dermatologist and skin cancer expert like Dr. Thomas Knackstedt.

Here’s how the process generally unfolds (ideally the following paragraphs are separated by arrows):

Medical History

The team at Apex Skin Center will inquire about your medical history, including any previous skin conditions, sun exposure habits, radiation exposure, changes to your immune system, family history of skin cancer, and any symptoms or changes in the skin or nails.

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Physical Examination

Board-certified dermatologist Dr. Thomas Knackstedt will conduct a thorough examination of the skin, focusing on any suspicious lesions or growths including an examination of all nails. Dermoscopy, a tool that allows for the magnification of structures within a skin growth is used to aid in the diagnosis of squamous cell carcinoma.

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Nail Unit Biopsy

If Dr. Knackstedt suspects nail unit squamous cell carcinoma based on the physical examination and dermoscopy findings, a nail unit biopsy may be performed. During a nail unit biopsy, a small sample of tissue is removed from the suspicious lesion under local anesthesia (numbing) and sent to a laboratory for analysis. The tissue is examined under a microscope to confirm the presence of squamous cell carcinoma and to assess the cancer’s characteristics

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Once the diagnosis of squamous cell carcinoma is confirmed, further evaluation may be necessary to determine the extent of the cancer and plan appropriate treatment. As a fellowship trained, board-certified Mohs surgeon and dermatology oncologist (cancer specialist), Dr. Thomas Knackstedt and the team at Apex Skin Center have significant expertise in the management of all types of skin cancer and nail cancers. Dr. Knackstedt has authored over twenty papers on squamous cell carcinoma and has co-authored one of the definitive book chapters on nail cancer surgery.