Page 409 - Medicine and Surgery

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Chapter 9: Skin and soft tissue lumps 405

Benign naevi Large haemangiomas can trap platelets leading to
thrombocytopenia (Kasabach–Merritt syndrome).
Definition Port-wine stains are irregular reddish-purple mac-
Anaevus is a hamartoma of the skin (a benign over-
ules caused by permanent vascular dilatation, which
growth of normal tissue). A melanocytic naevus is a pro-
may darken and become irregular with age. They
liferation of pigmented melanocytes.
are treated with laser therapy. A port-wine stain in
Melanocytic naevi occurring only in the dermal–

the ophthalmic division of the trigeminal nerve may
epidermal junction are referred to as junctional naevi.
have an associated vascular malformation in the brain
Melanocytic naevi occurring only in the dermis are

or meninges leading to epilepsy, hemiplegia and de-
referred to as dermal naevi. Blue naevi are acquired
velopmental delay (Sturge–Weber syndrome).
naevi occurring in the mid dermis.
Pyogenic granuloma is an acquired haemangioma
Melanocytic naevi in the dermal–epidermal junction

consisting of a bright red or blood-crusted nodule,
and the dermis are referred to as compound naevi.
which often follows trauma. Surgical curettage is pos-
sible but they occasionally recur.
Aetiology/pathophysiology
Almost all naevi are benign, but malignant change may
occur with junctional naevi at greatest risk. There is a Lipoma
familial dysplastic naevus syndrome (autosomal domi-
Definition
nant, gene on the short arm of chromosome 1).
A lipoma is a lobulated slow growing benign tumour of
fatty tissue encased by a thin fibrous capsule.
Clinical features
All individuals have one or more benign naevi, they
appear as small hyperpigmented flat or slightly raised Clinical features
Lipomastypicallypresentassoft,fluctuantmassseparate
areas of skin. Atypical features and those suggestive
from the overlying skin. Lipomas that occur in the fat
of malignancy are described later in section Malignant
of intramuscular septa become more prominent when
Melanoma (see page 407).
the muscle is contracted. Soft tissue X-ray confirms a
radiolucent mass.
Management
Benign naevi do not require any treatment. If there is
any diagnostic uncertainty an elliptical excision biopsy Management
and histopathological evaluation should be performed. Lipoma may require surgical removal.
Haemangiomas Epidermoid cysts
Definition Definition
Ahaemangioma is an arteriovenous malformation or An epidermoid cyst is an epithelium-lined cavity within
proliferation of abnormal blood vessels. the dermis filled with oily or fatty semisolid material.
Astrawberry naevus or capillary cavernous hae-

mangioma is a raised nodular patch of strawberry- Aetiology/pathophysiology
coloured skin, which can appear anywhere on the Epidermoid cysts are common in the hair-bearing areas
body.Theyusuallydevelopinthefirstfewweeksoflife, and are thought to arise from the blockage of a hair
growtoamaximuminthefirstyearandthengradually follicle. The commonest scalp cysts are pilar cysts, which
resolve. Treatment is not required unless they involve may be inherited.
the eye, bleed or become recurrently infected. Treat-
ments include laser therapy and courses of steroids. Clinical features
Cavernous haemangioma are larger and deeper vas- Patients present with a lump in the skin, so the skin can-

cular lesions, which may be covered by normal skin. not be moved over it. A characteristic surface punctum