Benign skin lesions

	This lesion is variously known a a seborrhoeic keratosis, basal cell papilloma or seborrhoeic wart.  They are common in the elderly and have varying degrees of pigmentation from pale brown to black.  They have a characteristic 'stuck on' appearance.  They can usually be easily differentiated from malignant melanomas.  Treatment is by superficial shaving or cautery.
	Congenital naevi can be single or multiple and vary greatly in size.  They are usually evenly pigmented with a regular border and may contain hairs.  Giant pigmented naevi often occur in a bathing trunk distribution.  Histologically they can be compound or intradermal lesions.  Giant naevi have a propensity to malignant change and this can occur in childhood.  Total excision and skin grafting of the naevus may be required.
	This lesion is a benign Spitz naevus or juvenile melanoma.  It has distinctive clinical and histological features and its importance lies in the fact that histologically it can be difficult to distinguish from a malignant melanoma.  They usually occur in children and young adults with a predilection to occur on the head, neck and lower limbs.  Histologically the most important feature is symmetry of the lesion on low power examination.  Treatment is by local excision.  Complete regression of lesions often occurs
	This pigmented skin lesion is a halo naevus.  They may be multiple and occur most commonly on the back of young adults. The halo is not a sinister feature and results from destruction of melanocytes by a lymphocytic infiltrate.  The area of depigmentation may persists for several years but re-pigmentation occurs in almost all cases. No treatment is required unless there are other features that suggest malignant change.
	This rapidly growing, pedunculated lesion is a pyogenic granuloma.  They frequently occur on the hand following minor trauma.  They increase in size over one or two weeks and if untreated eventually regress.  Histologically they are capillary haemangiomas.  Surgical excision or curettage should be considered if the lesion is painful or inconvenient.

Bibliography

Pandya K A,  Radke F.  Benign skin lesions: Lipomas, epidermal inclusion cysts, muscle and nerve Biopsies.  Surg Clin North Am 2009;  89:  677-687.

Priser R J.  Benign neoplasms of the skin.  Med Clin North Am 1998;  82:  1285-1307

Schaffer J V,  Bolognia J L.  The clinical spectrum of pigmented lesions.  Clin Plast Surg 2000;  27:  391-408