15. Epidermal nevi, neoplasms, and cysts

Seborrheic keratosis Other names Seborrheic verruca, basal cell papilloma, senile wart,[1][2]:767[3]:637 Multiple seborrheic keratoses on the dorsum of a patient with Leser–Trélat sign. Specialty Dermatology A seborrheic keratosis is a non-cancerous (benign) skin tumour that originates from cells in the outer layer of the skin. Like liver spots, seborrheic keratoses are seen more often as people age.[4] The tumours (also… read more »

Squamous cell skin cancer Other names Cutaneous squamous cell carcinoma (cSCC), epidermoid carcinoma, squamous cell epithelioma SCC of the skin tends to arise from pre-malignant lesions, actinic keratoses; surface is usually scaly and often ulcerates (as shown here). Specialty Dermatology, plastic surgery, otorhinolaryngology Symptoms Hard lump with a scaly top or ulceration.[1] Risk factors Ultraviolet radiation, actinic keratosis, lighter skin, arsenic exposure, radiation… read more »

Keratoacanthoma Keratoacanthoma Specialty Dermatology, plastic surgery Types Giant keratoacanthomas Subungual keratoacanthoma Multiple keratoacanthomas (Ferguson–Smith syndrome) Keratoacanthoma centrifugum marginatum Generalized eruptive keratoacanthoma of Grzybowski Risk factors Ultraviolet radiation, immunosuppression, genetics Diagnostic method Tissue biopsy Differential diagnosis Squamous cell skin cancer Treatment Surgery (excision, Mohs surgery) Keratoacanthoma (KA) is a common low-grade (unlikely to metastasize or invade) rapidly-growing skin tumour that is… read more »

Actinic keratosis Other names Solar keratosis, senile keratosis (SK) Actinic keratosis seen on the back of the hands Specialty Dermatology Actinic keratosis (AK), sometimes called solar keratosis or senile keratosis,[1][2] is a pre-cancerous[3] area of thick, scaly, or crusty skin.[4][5] Actinic keratosis is a disorder (-osis) of epidermal keratinocytes that is induced by ultraviolet (UV) light exposure (actin-).[6] These growths are more common in fair-skinned people and those who are frequently… read more »

Basal-cell carcinoma Other names Basal-cell skin cancer, basalioma Ulcerated basal-cell carcinoma affecting the skin of the nose in an elderly individual Specialty Dermatology, oncology Symptoms Painless raised area of skin that may be shiny with small blood vessel running over it or ulceration[1] Risk factors Light skin, ultraviolet light, radiation therapy, arsenic, poor immune function[2] Diagnostic method Examination, skin biopsy[3] Differential diagnosis Milia, seborrheic… read more »