subject: Benign tumours and cysts [print this page] Benign tumours and cysts Benign tumours and cysts
The growth of these is usually slow, does not destroy normal tissues and is eventually self-limiting. The lesion produced is generally symmetrical in shape.Seborrhoeic warts are one of the commonest skin abnormalities,occurring with increasing frequency with advancing years. The lesions vary in colour from pale brown tovery dark brown/black, and usually look as though they have been 'stuck on'. The surface is irregular and rather greasy to the touch. The simplest treatment is freezing with liquid nitrogen, although this is only necessary if the lesionis causing symptoms.Dermatofibromas (histiocytomas) normally present asfirm papules, 0.5-1 cm in diameter (although occasionally they are significantly larger). The lesion moves easily within the skin and is never fixed to deeper tissues. If the diagnosis is certain dermatofibromas can safely be left,but excision is the treatment of choice if this is deemednecessary.Pyogenic granulomas grow rapidly, often followingtauma and often on a digit. They are more common inchildren and young adults, but may be seen at any age.The surface is red, friable, and bleeds easily, consistingas it does of vascular proliferative tissue. In most instancesa thin epithelium eventually extends to cover the rawsurface, and lesions may involute spontaneously. It ismore practical, however, to remove the whole lesion bycurettage or by excision; the tissue should always be sentfor histopathology. Smaller tumours may respond tocryotherapy.Skin tags develop in clusters around the neck, axillae andgroins, more commonly in the obese (although thereappears to be an inherited tendency in some families).Occasionally there may be a background of mild acanthosisnigricansLesions catch on clothing and jewellery and can be removed easily with a pair of scissorsor by diathermy.Lipomas may be solitary or multiple, a tendency tonumerous lipomas being inherited as an autosomal dominanttrait in some families. They feel soft, subcutaneousand, as they enlarge, lobulated. Some lesions are mildlypainful when knocked. There is no satisfactory therapyother than formal excision.Kemtoacanthomas are rapidly growing and, by definition,self-limiting tumours with a histopathology that maybe difficult to distinguish from a well-differentiated squamouscell carcinoma. They arise most commonly on thehead and neck, the hand and forearm and on sun-damagedskin in general. The normal course of events is forthe lesion to grow rapidly over 4-6 weeks, reaching amaximum of about 2-3 cm in diameter. Growth thenceases, and a period of quiescence is followed by equallyrapid shrinkage and disappearance. There is often a smallpit left in the skin. The lesions are highly characteristic inshape, annular with a central keratin plug,but thesefeaures are shared by some invasive squamous cell carcinomas(see below) and complete removal is recommendedunless the patient is very old and frail.Epithelioid cysts and pilar cysts are both frequentlycalled 'sebaceous cysts' by the terminologically inexact.Both consist of spheres of epithelium producing keratinousmaterial internally. This results in a smooth, round swellingwhich moves easily over deeper structures in mostinstances. Occasionally inflammation and subsequent scarringleads to a tethered feel. Epithelioid cysts may occuranywhere, but are most common on the face, neck andtrunk. They frequently follow in the wake of severe acneand there may be a small punctum on the surface. Pilarcysts are essentially a malformation of hair root sheath andare normally found on the scalp. There is often a positivefamily history. Another common keratinizing cyst is themilium, which are usually multiple (milia). They may arisein scars or other areas of trauma, but are most commonlyfound on the face, either in clusters around the eyes ormore widely scattered, when they may be associated withsigns of chronic sun damage.Keloid. A keloid is an excessive growth of connectivetissue after an injury (including surgery or infection).Unlike a hypertrophic scar, it tends to grow beyond thelimits of the initial trauma and can occur spontaneously.Keloids are very long lasting. They are firm, smooth,rounded, protuberant swellings, often itchy and sensitive.In whites they tend to be purplish, and in dark-skinnedpatients they are often hyperpigmented. They are commonin black races and at certain sites, e.g. the sternum, shoulders,upper back and the beard area.Treatments include injections of corticosteroid, compressionand applications of silicone sheeting.
