Benign Skin Lesions Flashcards
What is a keratoacanthoma?
Dome-shaped erythematous lesions that develop over a period of days and grow rapidly. They often contain a central pit of keratin. They then begin to necrose and slough off. They are generally benign lesions although some do view them as precursors of malignancy. Curettage and cautery may treat them. If there is diagnostic doubt (they can mimic malignancy) then formal excision biopsy is warranted.
What is a pyogenic granuloma and how can they be treated?
These present as friable overgrowths of granulation at sites of minor trauma. They may be ulcerated and bleeding on contact is common. Typically, on the fingers and associated with pregnancy.
Rule out amelanotic melanoma and treated with curettage and cautery; formal excision may be used if there is diagnostic doubt.
What are congenital melanocytic naevi
Congenital melanocytic naevi – usually >1cm present at birth or in the early neonatal period. If >20cm there is an increased risk of malignant change
What are acquired melanocytic naevi?
Acquire melanocytic naevi – these appear in childhood and follow a specific pattern of maturation.
Describe the pattern of maturation of an acquired melanocytic naevi
- Flat evenly pigmented naevi with nests of melanocytes inside termed junctional naevus
- As more melanocytes migrate from epidermis to the dermis the mole becomes raised but is still evenly pigmented and is called a compound naevus
- Finally, the epidermal melanocytes are lost and the mole becomes a pale brown papule and will eventually regress, termed a intradermal naevus
What is a Halo naevus?
Halo Naevus – common in adolescence, a melanocytic naevus with a white halo around it. Completely benign occurring due to lymphocyte removal of melanocytes. IN adults they may indicate melanoma elsewhere.
What are seborrheic keratoses?
These are greasy brown warty lesions usually on the back, chest and face. They can be flat, raised filiform or pedunculated. They are extremely common in the elderly. Usually seen over places which see a high rate of friction. Large variation in colour from flesh to brown but have a stuck-on appearance.
What are epidermoid/pilar cysts?
Central Punctum, containing small quantities of sebum. The cyst lining is either normal epidermis (epidermoid cyst) or out root sheath of a hair follicle (pilar cyst)
What are dermatofibromas?
Solitary dermal nodule effecting the extremities of young adults. The lesions often feel larger than they appear. They are formed by proliferation fibroblasts merging with sparsely cellular dermal tissues.
