Basal Cell Carcinoma Differential Diagnosis Table

Basal Cell Carcinoma Differential Diagnosis Table:

Basal cell carcinoma is the most common, locally invasive, slow-growing, non-melanoma type of skin cancer. It mostly develops on sun-exposed areas of skin such as the face, head, and neck. It can also develop on the trunk or extremities; and rarely, it may occur on hands, feet, and genitals.
It appears as a lump, ‘pearly’ bump, or lesion that’s pink or skin-colored on the epidermis (outer layer) of the skin. Other symptoms are dome-shaped skin growth with tiny blood vessels on the face, especially the nose, numbness, itching, extreme sensitivity, and a needle-pricking sensation on the skin. It can bleed easily.
Risk factors of BCC include chronic exposure to UV light, severe sunburns, radiation therapy to treat skin conditions like acne, increasing age, family history, fair skin, use of immunosuppressive drugs, long exposure to UV rays from the sun causes changes in DNA that result in BCC.
It can be prevented by using sunscreen, by avoiding long exposure to the sun in the daytime, avoiding tanning beds, use of protective clothing, and regularly self-assessment of the skin and consulting the doctor if changes appear on the skin.
Skin biopsy and clinical examination of the lump can help in diagnosis. If diagnosed and treated early, this tumor has good prognosis.

How To Distinguish BCC From Other Diseases

Distinguish Verruca Seborrheic from BCC – Diagnosis

Verruca seborrheic or seborrheic keratosis is a harmless, benign wart-like lesion on the face, trunk, and extremities. The features that distinguish them from BCC are:

• On dermoscopy, Verruca Seborrheic is a benign lesion while BCC is a non-melanocytic lesion.
• Verruca seborrheic’s typical features are tiny white starry cysts, irregular crypts, fissures, or ridges, blue-grey globules, while BCC has the absence of a pigmented network, focal ulceration, branch-like telangiectasia.
• Verruca seborrheic appears as a sign of skin aging while BCC is caused by damage to DNA due to exposure to the sun for a long period.
• Verruca seborrheic can be found anywhere on the body except palms, soles, and mucous membranes while BCC can be found rarely on palms, soles, and mucous membranes.

Distinguish Molluscum Contagiosum from BCC – Diagnosis

Molluscum contagiosum is a common infectious skin disease caused by the poxvirus (molluscum contagiosum virus). The features that distinguish them from BCC are:

• Molluscum contagiosum is caused by the poxvirus while BCC is caused by long exposure of the skin to the sun.
• Molluscum contagiosum spreads through person-to-person contact, scratching the skin, contact with infected skin, or infected sexual partners while BCC has no person-to-person spread.
• If left untreated, Molluscum contagiosum bumps usually disappear within a span of 6 months to 2 years on their own while BCC, if left untreated, the disease aggravates and penetrates deeper into the skin, muscles, bones, and cartilages.

Molluscum contagiosum is diagnosed through a medical history of physical contact with an infected person or skin, a physical examination of the lesion which shows small, dome-shaped bumps of varying size with a dimple in the center, and through skin scraping and visualizing it under a microscope.

Distinguish Squamous Cell Carcinoma from BCC – Diagnosis

Squamous cell carcinoma is a common type of skin cancer caused by the overproduction of squamous cells in the epidermis and middle layer of the skin. The features that distinguish them from BCC are;

• Squamous cell carcinoma originates from keratinocytes in the superficial layer of the epidermis while BCC originates from basal cells in the deeper layer of the epidermis.
• Squamous cell carcinoma, in addition to the skin, also spreads to internal organs like the lungs, esophagus, and thyroid while BCC is limited to the skin.
• Squamous cell carcinoma is a fast-growing tumor that spreads easily while BCC is a slow-growing tumor.
• Squamous cell carcinoma has an irregular ulcer with everted margins while BCC has round ulcers with raised or rolled-out margins.

Squamous cell carcinoma is diagnosed on clinical examination, blood tests, and biopsy, and to see its spread, CT, MRI, and lymph node biopsy can be performed. If diagnosed early, this tumor has a good survival rate.

Distinguish Actinic Keratosis from BCC – Diagnosis

Actinic Keratosis or Solar keratosis are very common precancerous lesions of the skin. It presents as rough, scaly spots or patches on the upper layer of the skin caused by too much exposure to UV rays of the sun. The features which distinguish them from BCC are;

• Actinic keratosis is a pre-cancerous lesion caused by exposure to UV light. Sometimes, it can turn into squamous cell carcinoma. While BCC is the most common type of skin cancer.
• Actinic Keratosis lesions present as flat to slightly raised patches or bumps with no central dimple. While BCC lesions have rolled edges with central depression.
• Actinic Keratosis doesn’t have sores while BCC has sores that don’t heal and may ooze.

Actinic keratosis can be diagnosed with clinical examination and biopsy. In some people, actinic keratosis regresses while in some it develops into SCC. If diagnosed and treated early, it has a good prognosis but can also recur after treatment.

Distinguish Dermatofibroma from BCC – Diagnosis

Dermatofibroma or histiocytoma is a common, harmless brownish to red-purple growth under the skin that is smaller in diameter and can vary in color or shape. The features which distinguish them from BCC are;

• Dermatofibroma presents as a round bump mostly under the skin while BCC presents as a growth or sore on the skin that won’t heal.
• Dermatofibroma is mostly present on lower extremities while BCC can occur anywhere but is mostly present in sun-exposed areas.
• On dermoscopy, dermatofibroma appears as a central irregular white scar-like patch with a light brown pigmented peripheral network while BCC appears as linear or branch-like telangiectasia, focal ulceration, absence of pigment network, and structureless areas on the periphery of the lesion.

Dermatofibroma is diagnosed by clinical examination of the lesion, a positive pinch test, dermoscopy, and skin biopsy. These are benign lesions with an excellent prognosis.

Distinguish Cyst from BCC – Diagnosis

A cyst is an abnormal small, pocket-like area of tissue filled with fluid, hair, blood, tissue, bone, or any foreign material, and it can be present on any part of the body. The features which distinguish them from BCC are;

• Cysts are round lumps present just underneath the skin, often filled with fluid or pus, while BCC appears as a lump or bump-like skin growth in the outer layer of the skin.
• Cysts may be caused by infection, injury, or any other issue that results in the blockage of the drainage system of the body, while BCC is caused by sun exposure or tanning beds.
• On examination, the cyst is moveable or changes shape when pressure is applied, while BCC is firm and doesn’t move.
• Cysts usually have pores in their center, while BCC is unlikely to have a pore.

Cysts are usually diagnosed by looking at them or clinical examination; it can also be confirmed by skin biopsy and visualization of the skin under the microscope. Cysts have varying prognosis and reoccurrence rate depending on the size of the cyst and where it is present on the body.

Distinguish Psoriasis from BCC – Diagnosis

Psoriasis is an autoimmune chronic skin disease caused by systemic inflammation. It causes raised, flaky patches with white or grey scales of skin that are hot, red, swollen, and often painful. The features that differentiate Psoriasis from BCC are;

• In psoriasis, the skin may itch at a very early stage of psoriasis. Itching is intense and usually affects the skin of joints and the scalp, while in BCC itching is mild and usually appears when patches grow larger in size. It mostly affects the face, neck, and sun-exposed areas.
• Psoriasis is a condition that causes a rapid increase in skin cell production. This chronic increase in cell production results in the formation of discolored patches and plaques, while in BCC, cancerous cells develop in the skin’s tissue.
• Psoriasis appears as plaques with silvery-white scales, dry and cracked skin that can bleed on itching, burning, and soreness on plaques and skin around it, while in BCC, there are unusual spots or bumps that may be raised or waxy, firm and taut and have an unusual color yellow, violet, or black.

There is no definite treatment to cure psoriasis. Topical or oral steroid creams and ointments can be used to help with symptoms and reduce flare-ups of the disease.

Distinguish Eczema from BCC – Diagnosis

Eczema or atopic dermatitis is a common, non-contagious, autoimmune, and chronic condition of the skin caused by contact with an irritant or an allergen. Eczema causes the skin barrier to weaken, resulting in dry, itching, inflamed, and bumpy skin. The features to distinguish eczema from BCC are;

• Eczema is caused by any chemical irritant, detergent, genetic factor, stress, and an allergen, while BCC has no such causative agent. It is caused by a change in DNA due to exposure to the sun.
• Eczema can be found in multiple locations all over the body, while BCC usually appears as a single discrete or isolated lesion or simply a red patch.
• Eczema usually appears on that part of the body that has the ability to bend, such as behind the knees, inner elbows, neck, and ankles, while BCC appears mostly on sun-exposed areas and less on other parts of the body.

Eczema can be diagnosed based on medical history, physical examination, skin biopsy, and skin patch test. Topical steroids, daily moisturization of the skin can help in reducing flare-ups and the severity of the disease, but it can’t be cured properly.

Distinguish Hemangioma from BCC – Diagnosis

Hemangioma is a common non-cancerous benign growth that appears as purple or red lumps on the skin. It is formed by rapidly dividing cells of blood vessels in the skin and internal organs. The features to distinguish hemangioma from BCC are;

• Most infantile hemangiomas are present at birth or within a few weeks of birth, while BCC mostly appears later in life.
• Hemangioma appears as bright red or raised plaques that are soft, well-demarcated, and compressible, while BCC shows shiny, pink papule or nodule with rolled margins or rodent ulcer appearance.
• Congenital Hemangioma can regress or involute over a span of 10 years, while BCC has a good cure rate but can rarely regress.

Hemangioma can be diagnosed based on clinical examination, CT scan, and MRI. Hemangiomas can be treated with medicine and surgical removal. It shows a good prognosis.

Distinguish Keloid from BCC – Diagnosis

Keloid is a type of raised, thickened scar formed when skin heals after an injury. They usually grow beyond the healed surface of the skin and form mostly on people with dark skin. The features to distinguish keloid from BCC are;

• Keloid is a non-cancerous overgrowth of scar tissue after an injury, while BCC is the most common type of skin cancer.
• Keloid is formed with fibroblast proliferation and excessive collagen deposition, while BCC is cancerous overproduction of basal cells.
• Sometimes keloid and BCC, due to their similar clinical presentation, are hard to differentiate. Skin biopsy is then used to differentiate them.
• Keloids usually don’t need any treatment, while BCC, if left untreated, can have serious consequences.

Keloid is diagnosed based on clinical history and examination. For confirmation of diagnosis, a biopsy can be performed. It is easy to treat keloid, but it can regrow.

Important Red Flags of Basal Cell Carcinoma

There are certain conditions. If present, one should immediately consult a doctor because they can be features of underlying basal cell carcinoma.

• A sore that is bleeding and doesn’t heal.
• An unusual colored lesion, blue, brown, and black with a slightly raised border.
• A flat, scaly area that is shiny.
• A rough, irritated, itching red patch.
• A shiny, skin-colored bump that is translucent.