Pigmented Lesions
Pigmented lesions present particular problems.
Several studies have shown that even the most experienced dermatologist
makes mistakes when it comes to differentiating the various pigmented
lumps and bumps. Moles and seborrhoeic warts are the commonest pigmented
lesions but these have to be distinguished from malignant melanoma,
dermatofibroma, pigmented basal cell carcinoma (rodent ulcer) and
angiomas of different types. Probably the greatest difficulty is
experienced in identifying lesions that are suspected of being malignant
melanoma. As already indicated, the diagnosis may be difficult and
what follows must only be regarded as brief notes and hints on the
topic. If there is any doubt the patient must be referred without
delay to a specialist with experience of these lesions.
Diagnostic pointers
Moles As malignant melanoma may arise from an existing
mole or from previously normal nonpigmented skin, the patient's
statement as to what was previously at the site of the presenting
lesion is not often much help. The following points may, however,
be of use:
- Ordinary moles gradually mature and later degenerate
and disappear so that they become much less numerous in the elderly.
- Inflammation in moles can be very difficult to distinguish from
malignant melanoma. It is particularly common on the face in hairy
moles whose hairs have been plucked; the mole enlarges suddenly,
becomes red and tender, and may discharge.
- Rapid increase in
size and depth of color in a pre-existing lesion must always be
taken seriously.
- Changes in the surface texture including erosion
and crusting may be indicative of malignancy.
- Pigmentation of
surrounding skin and/or satellite nodules are also bad signs.
Seborrhoeic warts
These develop on most people as they become older and are
often misdiagnosed as malignant melanoma.
- Their distinguishing feature is their wartiness which is not a feature of malignant melanoma.
- Seborrhoeic warts don't usually occur singly.
- They occur particularly
over the chest, shoulders, back and face.
- They often seem as
if they are stuck on the skin surface or are plaque-like.
- Their
pigmentation is usually lighter than that of moles and is uniform.
Basal cell carcinoma
This may be quite darkly pigmented - especially
the nodular sort and can confuse the unwary. They generally occur
on the face and usually have the pearly sheen of ordinary basal
cell carcinomas despite their pigmentation.
Histiocytoma (dermatofibroma)
This is a common type of fibrous nodule that mostly occurs on the
limbs of middle-aged and elderly people. They are often pigmented
(though not deeply) and are firm or even hard and seem deeply set
in the skin. Occasionally they have a slightly warty and scaling
surface. These lesions can also be confused with malignant melanoma.
Vasular Malformations
Angioma Another sort of skin lesion that
can be quite difficult to distinguish is the small vascular malformation
or angioma. The blood in these may suddenly clot and turn black,
sometimes causing alarm in inexperienced doctors.
Pyogenic granuloma
A red, shiny or eroded nodule may suddenly appear which consists
of a mass of young capillaries. These are inappropriately called
pyogenic granulomas (inappropriately, because they are neither pus-forming
- pyogenic - nor due to granulomatous inflammation). Unfortunately
malignant melanoma can look just like pyogenic granuloma especially
if it is rapidly growing and nonpigmented.
Warty Lesions When most
people talk of warts they mean viral warts, and this is how I shall
use the term here. Warts are probably the commonest tumour of all;
most of us have some warts at some stage and most disappear without
specific treatment. The sites most often affected are the hand and
fingers, the soles of the feet, the genitalia and the face - but
they can occur virtually anywhere. Warts have different clinical
appearances depending on the particular type of wart virus involved,
the anatomical site infected and the resistance of the subject concerned:
- On the hands viral warts are usually either proper warty nodules
or small flat papules. The latter are either whitish-grey or pink
and are known as plane warts.
- On the soles, warts are either
hard callous nodules or large plaques consisting of a mass of faceted
papules (mosaic warts).
- Warts on the face or on the genitalia
often project straight out like horny spines or look like small
cauliflowers. These are known as filiform warts.
Diagnostic problems
When large numbers of warts occur on the hand or feet of youngsters
there is usually no difficulty in diagnosis. Some problems may arise
in older subjects when the differentiation between viral warts,
seborrhoeic warts, solar keratoses and even squamous cell carcinoma
may be difficult. Squamous cell carcinoma should be suspected if
the lesion is large and indurated. Hyperkeratotic warty and ulcerated
types both occur. Particular care should be taken with solitary
warty lesions in elderly subjects. Although they may look like ordinary
warts such lesions may actually be squamous cell carcinoma.
On the
face, clusters of pink plane warts around the mouth and chin may
look like acne or rosacea - such misdiagnoses are not as uncommon
as you might think. Plane warts on the face tend to be uniform in
appearance and not as inflamed as the lesions of acne and rosacea
