 |
|
|
|
Tumours of the Skin
Appendages |
Back to Library |
The skin appendages that most frequently give
rise to tumours are the pilosebaceous apparatus and the eccrine ducts and
glands. Tumours of apocrine glands are rare.
Two common tumours are derived from hair follicles: trichoepithelioma and
pilomatrixoma
Trichoepithelioma commonly presents as a skin-covered nodule, less than one
centimetre in diameter, on the faces of teenagers and young and middle-aged
adults. Both clinically and histologically, these lesions resemble small nodular
basal-cell carcinomas. The difference in age incidence is the main distinction
between the two.
Pilomatrixomas occur mainly in children, arising on the face, neck and
shoulders. They are raised, knobbly, dermal tumours, up to 2 cm in diameter,
which are often very pale or white with thin epidermis stretched over them.
¶Tumours or tumour-like nodules derived from the sebaceous component of the hair
follicle most frequently occur on the face. The most common is {\B sebaceous
hyperplasia,} in which there are a number of yellow papules, usually on the
forehead, cheeks and the area around the nose. They mainly affect elderly men
and, less commonly, women; clinically they may be mistaken for small basal-cell
carcinomas.
Tumours derived from eccrine sweat glands and their ducts are not common, but
there are many different types
The main types are:
• Syringoma. Multiple, small, pale white nodules or papules on the lower eyelids
and cheek, usually in women.
• Eccrine poroma. A raised, solitary, fleshy tumour, usually situated on the
sole but occasionally seen in the palm.
• Hidroacanthoma simplex. Usually located on the lower leg in elderly people,
often confused clinically with basal-cell carcinoma or seborrhoeic keratosis.
• Clear-cell acanthoma. A flat or slightly raised reddish lesion on the legs.
• Clear-cell or eccrine hidradenoma. Usually located on the head or neck of
young adults. Arises as a solitary nodular tumour which may appear cystic. Solid
lesions are usually flesh-coloured or slightly red; cystic lesions may have a
bluish tinge.
• Cylindroma. One of the most common tumours, the majority occurring on the
head, scalp and neck as slow-growing, pink, raised nodules. They are
particularly common in women, and multiple cylindromas may occur with an
autosomal dominant mode of inheritance. Multiple tumours on the scalp are
sometimes called 'turban tumour'.
Most skin cysts are derived from skin appendages
The most common skin cyst derived from a skin appendage is the so-called pilar
cyst, which occurs on the scalp of the elderly as a well-circumscribed, round
tumour. Histologically, lesions are lined by squamous epithelium similar to that
of hair follicles and contain thick, white, compacted keratin. They may be
multiple.
Epidermal cysts are also believed to be derived from hair follicles and are very
similar to pilar cysts. They are mainly seen on the face, neck and upper trunk
in young and middle-aged adults, and may occur in an area previously damaged by
severe acne. Similar epidermal cysts may be seen at the angle of the eye in
children (external angular dermoid) and are regarded as congenital
malformations. Epidermal cysts may also be seen anywhere on the body following
penetrating injury and are believed to be derived from squamous epithelium from
the epidermis, implanted during trauma (inclusion dermoid). The skin and
subcutaneous tissue around some epidermal cysts may show reddening and swelling,
and the lesion becomes tender. This is commonly called 'infected epidermoid
cyst,' but the inflammation is caused by leakage of keratin into surrounding
tissues following trauma and is not associated with infection. |
|
|
Interested in translating health topics to somali language! |
|
|
|
|
We give here simplified and accurate information about the disease
Info@somalidoc.com |
DISCLAIMER: This website is provided for
general information and it's run by medical students for medical students only
and is not a substitute for professional medical advice. We are not responsible
or liable for any diagnosis or action made by a user based on the content of
this website. We are not liable for the contents of any external websites
listed, nor do we endorse any commercial product or service mentioned or advised
on any of the sites. Always consult your own doctor if you are in any way
concerned about your health |
