Steatocystoma multiplex is a gene-related condition characterized by cysts on the upper arms, chest, and face, but cysts may occur in other parts of the body. The condition is caused by mutations in the KRT17 gene. Most cases are sporadic, meaning there are no other cases in a family. Other cases are inherited. Steatocystoma multiplex is also called sebocystomatosis, and in some cases, epidermal polycystic disease.
Definition & Facts
The condition is considered congenital, that is, present at birth, but multiple cysts may not develop on a person's body until puberty or sometime after that timeline. The disease was first identified in 1873, and it was named in 1899. It is an uncommon disorder of the pilosebaceous unit which consists of the sebaceous gland, arrector pili muscles, hair follicle, and hair.
Symptoms & Complaints
These benign cysts are filled with a yellowish, oily fluid, and it’s not uncommon for the cysts to have hair in them. Some cysts can leak sebaceous fluid, but that is not very common. The cysts can develop at various times in a person’s life, and they can become infected and cause scarring.
There can be pain associated with the cysts. The condition can manifest in childhood as red papules on the face, or it could cause calculi in the kidneys. Ureteral calculi and renal calculi can be related to the mutation of the KRT17 gene. Less than eight percent of kidney stones or other dangerous calcium deposits in organs are the result of the KRT17 mutated gene.
The primary cause of sebocystomatosis is mutations in the KRT17 gene. When mutations in that gene exist, sebocystomatosis will be passed to family members. That’s not necessarily the case. Cysts may develop sporadically in certain individuals. In those cases, there is not a family history of the condition.
The exact cause has not been identified in sporadic cases. Some researchers think that other conditions like hypohidrosis, acrokeratosis verruciformis, and hypertrophic lichen planus may be associated with sebocystomatosis. Other research suggests that steatocystoma multiplex is a variation of pachyonychia congenita. Both of those conditions share the same basic etiology, but there is a possibility that sebocystomatosis is also associated with eruptive hair cysts.
Both diseases share certain clinical features like the location, the appearance of the lesions, the age of onset, and the mode of inheritance. There are reports that hybrid lesions that have the features of both diseases exist. The existence of these hybrids may mean that steatocystoma multiplex and eruptive vellus hair cysts are variations of the same underlying disease. That argument has been challenged by other researchers.
Diagnosis & Tests
Doctors usually study a person’s symptoms and medical history. A physical examination comes next. Blood samples are taken, and once the laboratory results come back, a diagnosis is made. More than 14 mutations have been discovered in patients with steatocystoma multiplex or pachyonychia congenita type 2. All of those mutations are located in the helix initiation domain of the KRT17 gene.
Treatment & Therapy
Treatments for steatocystoma multiplex are limited. Known treatment approaches are not as successful as some people want them to be. Removing the cysts surgically is a common treatment, but the cost and cosmetic concerns, coupled with the time and pain, can make surgery an unattractive option. Shrinking the cysts using oral isotretinoin is another option, but it is temporary.
Some patients are prescribed tetracycline and other antibiotics to reduce swelling and redness. Draining cysts is another treatment. Laser treatments may help patients with numerous cysts as well as patients that have tried other treatments that have failed. The number and the location of cysts make treatment and therapy difficult. Some patients have hundreds of cysts all over their body, and other patients have thousands of cysts.
There are organizations and support groups that help patients cope with the issues that are associated with steatocystoma multiplex or pachyonychia congenita type 2.
Prevention & Prophylaxis
These groups provide support, raise awareness, and give patients new information about the research developments that may prevent or completely eliminate the cysts in the future. Several groups have medical researchers and medical advisors available to help patients understand the cosmetic and mental issues associated with steatocystoma multiplex.
Some of the organizations that support patients with this disease are the American Academy of Dermatology, the American Osteopathic College of Dermatology, the American Skin Association, and the British Association of Dermatology.