Squamous-cell skin cancer, also known as cutaneous squamous-cell carcinoma (cSCC), is one of the main types of skin cancer along with basal cell cancer, and melanoma. It usually presents as a hard lump with a scaly top but can also form an ulcer. Onset is often over months. Squamous-cell skin cancer is more likely to spread to distant areas than basal cell cancer. When confined to the outermost layer of the skin, a precancerous or in situ form of cSCC is known as Bowen's disease.
Melanoma, also known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin but may rarely occur in the mouth, intestines or eye. In women, they most commonly occur on the legs, while in men they most commonly occur on the back. About 25% of melanomas develop from moles. Changes in a mole that can indicate melanoma include an increase in size, irregular edges, change in color, itchiness or skin breakdown.
Melanoma is a group of serious skin cancers that arise from pigment cells (melanocytes); acral lentiginous melanoma is a kind of lentiginous skin melanoma. Although acral lentiginous melanoma is rare in people with lighter skin types, it is the most common subtype in people with darker skins. Acral lentiginous melanoma is observed on the palms, soles, under the nails and in the oral mucosa. It occurs on non-hair-bearing surfaces of the body, which have not necessarily been exposed to sunlight. It is also found on mucous membranes. It is the most common form of melanoma diagnosed amongst Asian and sub-Saharan African ethnic groups. The average age at diagnosis is between sixty and seventy years.
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.
Hyperkeratosis is thickening of the stratum corneum, often associated with the presence of an abnormal quantity of keratin, and also usually accompanied by an increase in the granular layer. As the corneum layer normally varies greatly in thickness in different sites, some experience is needed to assess minor degrees of hyperkeratosis.
The congenital melanocytic nevus is a type of melanocytic nevus found in infants at birth. This type of birthmark occurs in an estimated 1% of infants worldwide; it is located in the area of the head and neck 15% of the time.
Blue nevus is a type of melanocytic nevus. The blue colour is caused by the pigment being deeper in the skin than in ordinary nevi. In principle they are harmless but they can sometimes be mimicked by malignant lesions, i.e. some melanomas can look like a blue nevus.
Amelanotic melanoma is a type of skin cancer in which the cells do not make any melanin. They can be pink, red, purple or of normal skin color, and are therefore difficult to diagnose correctly. They can occur anywhere on the body, just as a typical melanoma can.
Trichoepithelioma is a neoplasm of the adnexa of the skin. Its appearance is similar to basal cell carcinoma.
A Spitz nevus is a benign skin lesion. A type of melanocytic nevus, it affects the epidermis and dermis.
In medicine, desmoplasia is the growth of fibrous or connective tissue. It is also called desmoplastic reaction to emphasize that it is secondary to an insult. Desmoplasia may occur around a neoplasm, causing dense fibrosis around the tumor, or scar tissue (adhesions) within the abdomen after abdominal surgery.
Cutaneous lymphoid hyperplasia refers to a groups of benign cutaneous disorders characterized by collections of lymphocytes, macrophages, and dendritic cells in the skin. Conditions included in this groups are:
A benign melanocytic nevus is a cutaneous condition characterised by well-circumscribed, pigmented, round or ovoid lesions, generally measuring from 2 to 6 mm in diameter. A benign melanocytic nevus may feature hair or pigmentation as well.
Pseudomelanoma is a cutaneous condition in which melantic skin lesions clinically resemble a superficial spreading melanoma at the site of a recent shave removal of a melanocytic nevus.
Mucosal melanoma is a rare condition characterized by a melanoma of the mucous membranes. This subtype is associated a worse prognosis than those arising from the skin. Mucosal melanomas occur in the head and neck (55%), anorectal (24%) and vulvovaginal region (18%), and in the urinary tract (3%). Based on the histopathologic and clinical features, melanomas of the vulva and vagina are often considered a separate disease entity. The prognosis of vulvovaginal melanomas is poor, especially for vaginal melanomas and has not improved over the last decades. While chemotherapy does not improve survival, checkpoint inhibitors have been tested in mucosal melanomas and have shown promising response rates.
A desmoplastic trichoepithelioma is a cutaneous condition characterized by a solitary, firm skin lesion on the face.
An acral nevus is a cutaneous condition characterized by a skin lesion that is usually macular or only slightly elevated, and may display uniform brown or dark brown color, but often with linear striations.
A pigmented spindle cell nevus is a skin condition characterized by a dark brown to black macule or papule, usually less than 6 mm.
