Benign growths

 Congenital naevi

Congenital (verrucous, epidermal) naevi(6) are common entities which may be single or multiple, and appear at birth or in early childhood. They are warty growths of brownish colour, but large horny excrescences may be present.

Keratin horn (Fig. 13.18)

This is also seen in old people and is a papilloma with excess keratin formation.

6Naevus (Latin) = a birthmark but often used to mean simply a mark or blemish on the skin.

Seborrhoeic keratosis (basal cell papilloma, seborrhoeic wart or senile wart)

This is a benign tumour caused by overgrowth of epidermal keratinocytes. They are frequently pigmented and often develop in large numbers on the trunk, face and arms of persons in or past middle life and are most common in the elderly. Seborrhoeic keratoses are very common in Caucasians and often are not mentioned by the patient, being accepted as harmless and part of the inevitable ageing process. Both sexes are equally affected. Usually they look like a verrucous plaque stuck on the epidermis, varying from dirty yellow to black and have loosely adherent, greasy keratin on the surface. They are usually ovoid, measuring from 1 mm to several centimetres. An eruption of seborrhoeic warts may be preceded by an inflammatory dermatosis. The superficial type has to be distinguished from simple and malignant lentigo. The domed pigmented variety may resemble a melanoma, especially if it is inflamed. However, with local antibacterial treatment and protection from injury, it returns to its normal state after a few days. If the lesions are asymptomatic removal is not required. Where treatment is indicated shave excision or curettage and diathermy leaves a flat surface that covers with normal epithelium in 1 week. Cryosurgery is also successful.

  Dermatofibroma (sclerosing angioma, histiocytoma, fibroma simplex, subepidermal nodular fibrosis)

This occurs in skin as firm, indolent, single or multiple nodules. Some follow minor trauma or insect bites, which may have acted as a trigger to this tissue reaction. It may possibly be a tumour of the dermal dendrocyte. In adults, the nodules are situated most commonly on the extremities, occurring in both sexes of all age groups after puberty (Fig. 13.19). They usually present as a small, well-defined nodule that may or may not be elevated above the surface of the skin. It is hard, button-like and freely mobile over the underlying tissues that touch the epidermis. They often itch, vary in size and ate frequently pigmented. Excision is only recommended for symptomatic nodules.

Molluscum fibrosum

Molluscum fibrosum are polypoid or filiform soft fleshy skin tags that occur on the neck, trunk and face. They are frequently found together with seborrhoeic warts. They are always pedunculated and frequently constricted at their base. They are round, soft, elastic and frequently pigmented. Treatment is by excision or cautery.

Pilomatrixoma

Pilomatrixoma (calcifying epithelioma of Malherbe) is a benign hair-follicle-derived tumour. These are solitary, hard turnouts that appear to be growing from the deep surface of the skin. They occur mostly on the face (Fig. 13.20), neck and arms. The size usually varies between 0.5 and 3 cm in diameter. The tumour may arise at any age but 60—80 per cent occur in the first two decades. Clinically, it resembles a rather hard epidermoid cyst.

Sebaceous adenoma

Isolated lesions are very rare. Multiple sebaceous adenomas occur in association with epilepsy in the condition tuberose sclerosis.

Cylindroma

Cylindroma (syn. ‘turban’ tumour) is so called from the arrangement of the stroma in peculiar transparent cylinders, which are thought to be of apocrine origim The tumour gradually forms an extensive, turban-like swelling extending over the scalp (Fig. 13.21). Ulceration is uncommon and the tumour is relatively benign. Cryotherapy may control the progression of this condition.

Rhinophyma (syn. potato nose) (Fig. 13.22)

This is a glandular form of acne rosacea. The skin of the nose, particularly the distal part, becomes immensely thick­ened and the openings of the sebaceous follicles are easily seen. The capillaries become dilated and the nose assumes a bluish-red colour. Surgical treatment, by paring away the excess tissue, gives a great improvement. Rarely, basal cell carcinomas are associated with this lesion.

Sarcoid (Boecks)

This is a generalised disease that may affect skin. In the skin it occurs as reddish-brown nodules which are soft and rarely ulcerate. Giant cells are found, but tubercule bacilli can never be isolated.

Cutaneous horns (Bland-Sutton)

These may be sebaceous horns (Fig. 13.16), wart or corn horns (Fig. 13.23), cicatrix horns (Fig. 13.24) or nail horns.