Most skin growths and spots are benign (noncancerous). However, new, changing, bleeding, or otherwise unusual lesions should be evaluated because skin cancers can sometimes resemble harmless skin conditions.

Warts
 

Warts are skin growths caused by human papillomavirus (HPV). They can occur almost anywhere and may spread to other areas of the body or to other people through direct or indirect contact.

Types include common warts, plantar warts, flat warts, and genital warts.

Genital Warts — Genital warts are sexually transmitted and are most commonly caused by HPV types 6 and 11. Genital warts are generally considered to be noncancerous. They can occur on or around the genitals or anus and typically spread through intimate skin-to-skin sexual contact. HPV vaccination (Gardasil 9) protects against HPV types 6 and 11 and can prevent most genital warts. The vaccine prevents new HPV infections, it but does not treat an existing HPV infection or existing genital warts. Flatter, smoother, moister, softer, and broader "warts" may actually be a sign of condyloma lata, which are lesions  caused by untreated syphilis.  

Many nongenital warts eventually disappear without treatment. Treatment options include salicylic acid, cryotherapy (freezing), and other topical or destructive treatments.

Precancerous & Cancerous Skin Lesions

Actinic Keratosis (Precancerous) — A rough, scaly, or crusty area caused by cumulative sun exposure. It commonly develops on the face, ears, scalp, forearms, and backs of the hands. Actinic keratoses can sometimes progress to squamous cell carcinoma and may require treatment.
 

Basal Cell Carcinoma (BCC) — The most common type of skin cancer. It often appears as a pearly or shiny bump, pink or skin-colored growth, nonhealing sore, or lesion that repeatedly bleeds, crusts, heals, and returns. BCC usually grows slowly and rarely spreads to distant parts of the body, but it can invade and damage surrounding tissue if untreated.
 

Squamous Cell Carcinoma (SCC) — A common skin cancer that may appear as a firm red or pink bump, scaly or crusted patch, rapidly growing lesion, or sore that does not heal. It commonly develops on chronically sun-exposed skin. SCC can invade deeper tissues and, unlike BCC, has a greater potential to spread to other parts of the body via the lymphatic system, circulatory system, or nervous system. 

Melanoma — A potentially aggressive cancer of melanocytes. Melanoma may develop within an existing mole or appear as a new lesion. Warning signs include the ABCDE features (A- Asymmetric; B- Border irregular or blurred or poorly defined; C- Color of multiple colors; D- Diameter larger than a pencil eraser; E- Evolving/changing mole). Melanoma has the greatest potential to spread to other parts of the body via the lymphatic system, circulatory system, or nervous system. 
 

Common Benign Skin Lesions
 

Skin Tags (Acrochordons) — Soft, benign growths commonly found around the neck, armpits, groin, eyelids, and other skin folds.

Seborrheic Keratoses — Very common benign growths that may be tan, brown, or black and often have a waxy, raised, or “stuck-on” appearance. They are associated with age.
 

Cherry Angiomas — Small, red growths made up of blood vessels. They are benign and can be associated with age and hormonal changes. 

Dermatofibromas — Firm, usually small benign bumps commonly found on the arms or legs. They may dimple inward when pinched from the sides. They may be associated with skin trauma. 
 

Epidermoid Cysts — Benign cysts that form from epithelial skin cells and contain keratin. They typically form a smooth lump and may have a visible central opening. They can occasionally become inflamed or infected.

Ganglion Cysts — Benign pseudocysts typically found near joints or tendon sheaths. They can be associated with trauma, in which joint fluid leaks out of the joint capsule or tendon sheath. They typically transilluminate. Aspiration may help, but surgery is the gold standard. 

Pilar Cysts — Benign cysts that develop from the outer root sheath of a hair follicle and occur most commonly on the scalp. They typically feel like smooth, firm, mobile lumps beneath the skin and, unlike epidermoid cysts, usually do not have a central punctum. Pilar cysts often run in families and may occur in multiples. 

Molluscum Contagiosum — A common, contagious skin infection caused by a poxvirus. It causes small, smooth, firm, flesh-colored or pearly bumps that often have a characteristic small indentation (dimple) in the center. It is especially common in children and can spread through direct skin contact, scratching, or shared objects such as towels. In adults, lesions in the genital region can be sexually transmitted. Molluscum is usually harmless and typically goes away on its own, although this may take months and sometimes longer. Treatment may be considered when lesions are bothersome, spreading extensively, or causing complications.

Lipomas — Benign tumors made of fatty tissue. They typically feel soft, rubbery, and mobile beneath the skin. They usually grow slowly.
 

Skin Biopsy
 

A suspicious or uncertain skin lesion may require a biopsy. A biopsy removes part or all of the lesion so it can be examined under a microscope.

Common techniques include:
 

• Shave biopsy

• Punch biopsy

• Excisional biopsy
   

                                                       References & Guidelines
 

• American Academy of Dermatology (AAD). Warts: Diagnosis and Treatment.

• American Academy of Dermatology (AAD). Moles and Melanoma: ABCDEs of Melanoma.

• Centers for Disease Control and Prevention (CDC). Human Papillomavirus (HPV) Infection and Anogenital Warts.

• Centers for Disease Control and Prevention (CDC). Molluscum Contagiosum.

• American Academy of Dermatology (AAD). Actinic Keratosis: Diagnosis and Treatment.

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