Most Common Skin Cancer Misdiagnoses

Skin cancer can be mistaken for a harmless mole, rash, wart, cyst, infection, or slow-healing sore. When a doctor overlooks visible changes, delays a biopsy, misreads pathology results, or fails to refer a patient to a dermatologist, the cancer may progress before the patient receives the right treatment.

Jacob D. Fuchsberg Law Firm represents New Yorkers harmed by cancer misdiagnosis and delayed diagnosis. If you suspect a mistake in your diagnosis, our exceptional NY cancer misdiagnosis lawyer could be your strongest ally. Here's an overview of the most common skin cancer misdiagnoses and their implications.

What Is Skin Cancer and How Often Is It Misdiagnosed?

Skin cancer develops when abnormal skin cells grow out of control. In many cases, the damage begins after exposure to ultraviolet radiation from sunlight or tanning beds. Skin cancer can appear as a new growth, a sore that does not heal, or a mole that changes in size, color, shape, or texture.

Misdiagnosis can happen at different points: during the first skin exam, after a lesion is dismissed as benign, when a biopsy is not ordered, or when pathology results are misread. Research shows why these cases can be difficult. A JAMA Network Open study found a 47.9% overall misclassification rate after a single interpretation of melanocytic skin lesions, with higher error rates for certain borderline or early melanoma categories.

What Are the Different Types of Skin Cancer?

Skin cancer comes in several distinct forms, which can primarily be classified under the following headings:

Melanoma

Melanoma is less common than basal cell carcinoma and squamous cell carcinoma, but it is more likely to spread. The American Cancer Society estimates that about 112,000 new invasive melanomas will be diagnosed in the United States in 2026, and about 8,510 people are expected to die from melanoma.

Melanoma may appear in an existing mole or as a new dark, irregular, or changing spot. It can also appear in less obvious places, including under a nail, on the scalp, on the soles of the feet, or inside the mouth.

Basal Cell Carcinoma

Basal cell carcinoma, or BCC, is the most common type of skin cancer. It often appears on areas exposed to the sun, such as the face, scalp, ears, neck, shoulders, and arms.

BCC may look like a pearly bump, a pink patch, a shiny scar-like area, or a sore that bleeds and heals repeatedly. Because it can appear harmless at first, doctors may mistake it for a cyst, an acne lesion, a scar, or a minor skin irritation.

Squamous Cell Carcinoma

Squamous cell carcinoma, or SCC, often appears as a rough, scaly patch, a firm red bump, a wart-like growth, or a sore that does not heal. It is common on sun-exposed skin, including the face, ears, lips, neck, hands, and arms. SCC may be mistaken for eczema, psoriasis, a wart, a skin infection, or an inflammatory skin condition.

Between melanoma and non-melanoma varieties like squamous cell carcinomas, skin cancer is the most common form of cancer diagnosed in the United States.

Most Common Skin Cancer Misdiagnoses

The complexity of many skin conditions can make it hard to recognize skin cancer with certainty. While diligent diagnosis is key, certain types of skin cancer can be mistaken for other benign or non-cancerous skin conditions.

Basal Cell Carcinoma Misdiagnosed as a Benign Skin Problem

Basal cell carcinoma may be mistaken for:

• A cyst
• Acne
• A scar
• A harmless bump
• A noncancerous lesion
• A recurring sore
• A minor infection

A doctor may need to order a biopsy if a spot bleeds, crusts over, grows, returns after treatment, or does not heal.

Squamous Cell Carcinoma Misdiagnosed as a Rash or Infection

Squamous cell carcinoma may be mistaken for:

• Eczema
• Psoriasis
• A wart
• A fungal infection
• A bacterial infection
• Actinic keratosis
• Dry or irritated skin

A provider should take a closer look when a scaly patch or lump grows, hurts, bleeds, thickens, or does not respond to medication.

Melanoma Misdiagnosed as a Benign Mole

Melanoma may be mistaken for:

• A normal mole
• A dysplastic mole
• A birthmark
• A bruise
• A blood blister
• A nail injury
• A harmless dark spot

Because these conditions can all resemble skin cancers, it's wise to consult a dermatologist about any sudden or suspicious skin changes.

Skin Cancer Warning Signs: A Self-Check Guide

Even though skin cancer might not always produce obvious symptoms, being vigilant about periodic self-examinations can be life-saving. Regular screening is highly valuable, particularly since early detection improves the chances of successful treatment.

For invasive melanoma, the deadliest form of skin cancer, watch for moles that grow, change shape, lose symmetry, develop uneven color, itch, bleed, or become inflamed. The ABCDE rule can help:

• A — asymmetry: One half of the mole does not match the other.
• B — border: The edges look uneven, blurred, jagged, or poorly defined.
• C — color: The spot has different shades of brown, black, red, blue, pink, or white.
• D — diameter: The spot is larger than a pencil eraser, although melanoma can be smaller.
• E — evolving: The mole changes in size, shape, color, height, sensation, or bleeding.

By comparison, the warning signs of non-melanoma skin cancers can be more subtle, such as persistent sores or spots that itch, bleed, or fail to heal within a month.

What to Do First If You Suspect Skin Cancer Was Misdiagnosed

If you suspect a missed or delayed skin cancer diagnosis, protect your health first. See a dermatologist, oncologist, or another qualified provider as soon as possible. Ask about the cancer type, stage, treatment plan, and whether earlier testing may have changed your care.

Save or request:

• Dermatology, primary care, urgent care, and hospital records
• Biopsy and pathology reports
• Pathology slides, if available
• Lab results and imaging reports
• Photos of the mole, lesion, rash, sore, or wound over time
• Patient portal messages
• Referral record
• Prescription records
• Bills, insurance statements, and out-of-pocket expenses
• Proof of missed work or reduced income
• Notes about dates, symptoms, conversations, and provider names

Under CPLR § 214-a, most New York medical malpractice claims must be filed within 2 years and 6 months of the error or last treatment for the same condition. For malignant tumor misdiagnosis, the filing window may start when the patient discovers the harm. However, these claims are subject to a strict 7-year limit from the original date of negligence.

Why Doctors Miss or Misdiagnose Skin Cancer

A mistake may occur when a provider relies solely on a quick visual exam rather than taking a full history, tracking changes, ordering a biopsy, or referring the patient to a dermatologist. Common reasons skin cancer is missed include:

• A changing mole is labeled “benign” without follow-up.
• A sore that does not heal is treated as an infection.
• A dark spot under a nail, on the foot, or on the scalp is overlooked.
• A biopsy is delayed, too shallow, or taken from the wrong area.
• A pathology report is misread or not communicated to the patient.
• A primary care doctor fails to refer the patient to a dermatologist.
• A dermatologist does not compare past images, notes, or patient complaints.

Not every delayed diagnosis is malpractice. A claim may exist when a doctor, clinic, dermatologist, pathologist, or hospital failed to exercise reasonable care, and that failure allowed the cancer to progress.