Squamous Cell Carcinoma

Squamous cell carcinoma is the second most common skin cancer, with more than a million tumors diagnosed in the United States each year. It arises from keratinocytes, the same cell of origin as basal cell carcinoma, which make up the majority of the epidermis, the tissue-paper-thin top layer of the skin.

If you have just been diagnosed, know first that squamous cell carcinoma is not melanoma, and the two are frequently confused. Most squamous cell carcinomas of the skin are removed with a single surgical procedure under local anesthesia in one day and are cured. The great majority never threaten a patient's life.

The honest distinction from basal cell carcinoma is this: while spread is still uncommon, it happens more often with squamous cell carcinoma. That is why prompt treatment and accurate risk assessment matter, and why certain tumors warrant margin-controlled surgery and closer follow-up rather than a simpler approach.

Squamous cell carcinoma favors chronically sun-exposed skin: the ears, particularly the helical rim, the lower lip, balding scalp, face, nose, neck, forearms, and backs of the hands.

Common presentations include:

• A firm, rough, scaly bump or nodule that may be tender to touch
• A thickened, wart-like growth, sometimes with a central crust or a horn-like projection
• An open sore that bleeds, crusts, and fails to heal over weeks
• A new or enlarging lesion arising within a scar, chronic wound, or previously irradiated skin

Squamous cell carcinoma often grows faster than basal cell carcinoma and is more likely to be tender or painful. Pain, numbness, or tingling around a lesion deserves prompt evaluation, as those symptoms can suggest involvement of a nerve.

Actinic keratoses are rough, scaly precancerous spots caused by sun damage. A small proportion progress to invasive squamous cell carcinoma, which is why dermatologists treat them with cryotherapy, topical medications, or field treatments before they advance.

Squamous cell carcinoma in situ, also called Bowen's disease, is confined to the epidermis and has not invaded deeper tissue. It cannot spread in that state and is highly curable, though it typically warrants definitive treatment because it can progress to invasive disease if left alone.

Not all squamous cell carcinomas carry the same risk. Features that raise the likelihood of recurrence or spread include:

• Larger tumor diameter, and greater depth of invasion on the biopsy report
• Poorly differentiated tumors under the microscope
• Perineural invasion, meaning tumor tracking along a nerve
• Location on the ear, lip, or in previously treated, scarred, or irradiated skin
• Recurrent tumors that have already been treated once
• A weakened immune system, particularly in solid organ transplant recipients, who develop squamous cell carcinoma far more frequently and with more aggressive behavior

These features drive the treatment recommendation. Higher-risk tumors benefit most from complete margin assessment, and a subset warrant imaging, multidisciplinary input, or evaluation of regional lymph nodes. Dr. Lopez coordinates with your referring physician and, when appropriate, with radiation and medical oncology.

Mohs micrographic surgery offers cure rates up to 99 percent for previously untreated squamous cell carcinoma, per the American College of Mohs Surgery (opens in new tab), and remains the only technique that examines 100 percent of the surgical margin.

The visible tumor and a thin margin are removed under local anesthesia. Dr. Lopez processes and reads the tissue himself while you wait, taking additional tissue only where cancer persists at the margin. Stages repeat until margins are clear. Complete margin assessment is especially valuable in squamous cell carcinoma because the tumor can extend along nerves and through scarred tissue in ways that are impossible to judge by eye.

Reconstruction follows the same day, in the same visit, once margins are confirmed clear. Dr. Lopez performs 99 percent of his own reconstructions.

As with basal cell carcinoma, Mohs is not the answer for every tumor. Small, thin, well-differentiated tumors on the trunk or extremities are often well served by standard excision or other approaches. Dr. Lopez will recommend the least invasive treatment that achieves a durable cure.

Dr. Lopez has personally performed over 10,000 Mohs micrographic surgery procedures since completing his Mayo Clinic fellowship in 2018, with 1,757 cases in 2025, of which 1,288 (73 percent) were on the head, neck, or other anatomically sensitive sites. Squamous cell carcinoma of the ear and lower lip is among the most frequent presentations he treats.

He accepts squamous cell carcinoma referrals, including high-risk and transplant-patient cases, from dermatologists, primary care physicians, plastic surgeons, oculoplastic surgeons, facial plastic surgeons, and radiation oncologists across Tampa Bay, including Wesley Chapel and Land O' Lakes.

Because the same sun exposure that produced one tumor affects the surrounding skin, patients with squamous cell carcinoma commonly develop additional keratinocyte cancers over time. Continued full-skin surveillance with your dermatologist is an essential part of care.