Benign
growths
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.
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.
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.