Steatocystoma multiplex, is a
benign
Malignancy () is the tendency of a medical condition to become progressively worse.
Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malign ...
,
autosomal dominant
In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and t ...
congenital condition resulting in multiple
cyst
A cyst is a closed sac, having a distinct envelope and cell division, division compared with the nearby Biological tissue, tissue. Hence, it is a cluster of Cell (biology), cells that have grouped together to form a sac (like the manner in which ...
s on a person's body.
Steatocystoma simplex is the solitary counterpart to steatocystoma multiplex.
In steatocystoma multiplex, the tendency to develop cysts is inherited in an autosomal dominant fashion, so one parent can be expected to also have steatocystoma multiplex. It may also occur sporadically. Both males and females may be affected.
The onset at puberty is presumably due to hormonal stimulus of the
pilosebaceous
A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called #Sebum, sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greates ...
unit. They most often arise on the chest and may also occur on the abdomen, upper arms, armpits and face. In some cases cysts may develop all over the body.
The cysts are mostly small (2–20 mm) but they may be several centimetres in diameter. They tend to be soft to firm semi-translucent bumps, and contain an oily, yellow liquid. Sometimes a small central punctum can be identified and they may contain one or more hairs (
eruptive vellus hair cyst Eruptive vellus hair cysts (or EVHC) are small lesions that occur most often in the chest wall, abdomen and extremities, often with a crusted surface. EVHC may occur randomly, or it can be inherited as an autosomal dominant trait. The condition af ...
s). They may become inflamed and heal with scarring, like acne nodules (see
nodulocystic acne and
hidradenitis suppurativa
Hidradenitis suppurativa (HS), sometimes known as acne inversa or Verneuil's disease, is a long-term dermatological condition characterized by the occurrence of inflamed and swollen lumps. These are typically painful and break open, releasing ...
).
On inflammation they can become incredibly painful and reach sizes between 4-6cm in diameter. The area around the cyst can become red and painful to the touch; making mobility, sitting, strenuous movement or everyday activities very difficult and painful.
Steatocystomas are thought to come from an abnormal lining of the passageway to the oil glands (sebaceous duct).
Localised, generalised, facial, acral, and suppurative types of steatocystoma multiplex have been described.
Causes
![Relative incidence of cutaneous cysts](https://upload.wikimedia.org/wikipedia/commons/b/b0/Relative_incidence_of_cutaneous_cysts.jpg)
It is associated with defects in
Keratin 17
Keratin, type I cytoskeletal 17 is a protein that in humans is encoded by the ''KRT17'' gene.
Keratin 17 is a type I cytokeratin. It is found in nail beds, hair follicles, sebaceous glands, and other epidermal appendages. Mutations in the gene en ...
.
The condition is inherited in an autosomal dominant manner. This indicates that the defective gene responsible for a disorder is located on an
autosome
An autosome is any chromosome that is not a sex chromosome. The members of an autosome pair in a diploid cell have the same morphology, unlike those in allosome, allosomal (sex chromosome) pairs, which may have different structures. The DNA in au ...
, and only one copy of the defective gene is sufficient to cause the disorder, when inherited from a parent who has the disorder.
However, a solitary case can also emerge in a family with no prior history of the disorder due to the occurrence of a
mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...
(often referred to as a sporadic or spontaneous mutation).
Diagnosis
It is difficult to diagnose genetic and rare diseases. Healthcare professionals would look at a combination of a patient's medical history, symptoms, physical exam and other laboratory tests to inform their diagnosis.
Treatment
The cysts can be removed via
excision, though conventional cyst excision techniques have proven impractical, and a specialized regimen is required.
Cryotherapy
Cryotherapy, sometimes known as cold therapy, is the local or general use of low temperatures in medical therapy. Cryotherapy may be used to treat a variety of tissue lesions. The most prominent use of the term refers to the surgical treatment, s ...
and electrosessication may also be tried, but since it is genetic disorder all the modalities have very little effect.
Individual cysts can be removed surgically. In most cases, small incisions (cuts into the skin) allow the cyst and its contents to be extracted through the opening. If it is tethered to the underlying skin, excision biopsy may be necessary. Cysts can also be removed by laser, electrosurgery or cryotherapy. Inflammation can be reduced with oral antibiotics. Oral
isotretinoin
Isotretinoin, also known as 13-''cis''-retinoic acid and sold under the brand name Accutane among others, is a medication primarily used to treat severe acne. It is also used to prevent certain skin cancers (squamous-cell carcinoma), and in th ...
is not curative but may temporarily shrink the cysts and reduce inflammation.
See also
*
Keratin disease
A keratin disease is a genetic disorder of one of the keratin genes. An example is monilethrix. The first to be identified was epidermolysis bullosa simplex.
Pathology
Examples of keratin disease include:
See also
* List of cutaneous condition ...
*
Steatocystoma simplex
*
List of cutaneous conditions
Many skin conditions affect the human integumentary system—the organ system covering the entire surface of the body and composed of skin, hair, nails, and related muscle and glands. The major function of this system is as a barrier against t ...
*
List of cutaneous conditions caused by mutations in keratins
There are many different keratin proteins normally expressed in the human integumentary system. Mutations in keratin proteins in the skin can cause disease.
Of note, other structural proteins in the epidermis of the skin that are closely rel ...
References
External links
{{Cytoskeletal defects
Epidermal nevi, neoplasms, and cysts
Cytoskeletal defects