What is Cutaneous Leiomyomas?
Cutaneous leiomyomas are rare, harmless tumors that form in the smooth muscles, the muscles involved in involuntary body functions. They are categorized according to where the muscle in the tumor comes from. The most common type, angioleiomyomas, develop from the middle layer of blood vessels. The other two types, piloleiomyomas and genital leiomyomas, originate from the small muscles associated with hair follicles and the smooth muscles found in male and female genital areas or nipples, respectively.
While the tumors are benign, people with multiple cutaneous leiomyomas (specifically, piloleiomyomas) might have a genetic mutation, which may heighten the chance of developing kidney cancer. Mutations might also cause the piloleiomyomas and genital leiomyomas to lead to pain or discomfort.
What Causes Cutaneous Leiomyomas?
Piloleiomyomas, a type of skin tumor associated with muscle fibers, can occur randomly or as part of a hereditary condition. One such condition is Reed’s syndrome, also known as Multiple Cutaneous and Uterine Leiomyomatosis (MCUL). This condition often results from a mutation in a gene responsible for making an enzyme called fumarate hydratase (FH). This enzyme plays a crucial role in a body’s metabolic process. When piloleiomyomas are linked to a genetic condition, they usually start appearing early in life, around the average age of 25.
However, the relationship between the mutation in the FH gene and the development of these skin tumors remains unclear. Scientists speculate that the FH gene might normally help prevent tumors, but the mutation disrupts this function.
According to a study in 2005, about 89% of patients with numerous skin leiomyomas have a mutation in the FH gene. Women with this mutation often have both piloleiomyomas (85%) and painful uterine fibroids (over 90%). Typically, these uterine fibroids are larger, develop at a younger age, and require more surgical intervention compared to non-hereditary uterine fibroids.
However, one of the main concerns of having a mutation in the FH gene is the link with an aggressive type of kidney cancer, which develops in around 15% of patients. This kidney cancer can unfortunately spread to other parts of the body at the time of diagnosis in about half of these patients.
It’s important to note that Reed’s syndrome, also known as Hereditary Leiomyomatosis with Renal Cell Carcinoma (HLRCC), does not mean a person has kidney cancer, despite it being part of the name. This title was given because of the increased risk associated with the condition.
Risk Factors and Frequency for Cutaneous Leiomyomas
The information about how often skin leiomyomas occur (the prevalence and incidence) is not widely available. It’s important to note that piloleiomyomas, a type of skin leiomyoma, are more commonly found in adults compared to children. There’s no difference in how often they occur in different races or between males and females. Of all skin leiomyomas, angioleiomyomas are the most common, followed by piloleiomyomas and, finally, genital leiomyomas.
Signs and Symptoms of Cutaneous Leiomyomas
Piloleiomyomas are skin conditions that show up as either a single skin bump or several bumps. These bumps can appear in different patterns like clustered, in a line, or scattered. They can also be present in two different spots on the body. Their size can range from 2mm to 20mm and may be the same color as your skin, pink, red, or reddish-brown. Single piloleiomyomas usually appear on the lower part of the body, while multiple ones often show up on the outer surfaces of the body and the trunk. People with several piloleiomyomas often experience pain, which may happen on its own or be triggered by pressure, cold, strong emotions, or a light touch. This pain is often described as sharp, shooting, or an ache. These lesions typically develop between the ages of 20 to 40.
Genital leiomyomas usually appear on the private parts, like the penis, scrotum, and vulva. They can also be found around the nipple. They usually show up as a painless, single bump. But sometimes, they may have a stalk and be mistaken for a skin tag or genital wart.
Angioleiomyomas generally show up in women in their 40s to 60s. They are often a firm, sometimes painful, lump under the skin on the lower part of the body.
Testing for Cutaneous Leiomyomas
If your doctor suspects that you have a skin condition called a cutaneous leiomyoma, they will often make this diagnosis based on physical examination and your medical history. However, a biopsy – a procedure to remove a small piece of skin for laboratory testing – is typically done to confirm the diagnosis. In general, no other tests beyond a biopsy are needed for genital leiomyomas or angioleiomyomas, which are similar types of skin conditions.
However, if you have multiple skin growths called piloleiomyomas, your doctor might recommend additional tests due to a strong link with HLRCC or Reed’s syndrome, both of which are genetic disorders. Some experts advise further evaluation even if you have only one confirmed piloleiomyoma.
There are several criteria, both major and minor, to aid in diagnosing hereditary leiomyomas and renal cell carcinoma (kidney cancer). The major criterium is having multiple confirmed piloleiomyomas. Minor criteria include having surgery for uterine leiomyomas – a type of fibroid tumor – before 40, developing type 2 papillary renal cell carcinoma before age 40, or having a close family member who meets the previous criteria. HLRCC could be the likely diagnosis if you meet the major criterion or two of the minor criteria.
Your doctor may order further tests if need be. For instance, a particular enzyme assay to evaluate for deficiency in an enzyme called fumarate hydratase, which is indicative of HLRCC when less than 60% active. Please note that rarely, patients with HLRCC may not show a fumarate hydratase deficiency.
HLRCC, recognized in 2001, is a relatively new genetic disease. Since its discovery, researchers found an association with renal cell carcinoma. Thus, early screening, starting around 8 to 10 years old, is vital as it may develop even in children. If positively diagnosed with HLRCC, you should have an annual MRI scan to monitor any developments related to kidney cancer. Similarly, adults with HLRCC should also undergo an MRI yearly. A full physical examination, a gynecological exam when appropriate, and skin check-ups twice a year are also recommended. Additionally, your close family members should get genetic testing for HLRCC and screenings for abdominal or pelvic abnormalities.
Treatment Options for Cutaneous Leiomyomas
Piloleiomyomas are a condition that can cause significant distress for both patients and doctors because of their tendency to return after surgical removal, and the lack of effective drug treatments. The chosen treatment method depends on how many piloleiomyomas the patient has, where they’re located, and how much discomfort they’re causing.
Surgical removal is the best option if the patient only has a few piloleiomyomas in one place. However, it’s important that the patient understands there’s a high chance these could return, sometimes as quickly as six weeks after being removed.
If the piloleiomyomas cover a larger area, or if the patient doesn’t want to risk them returning after the surgery, medication could be a better option. Treatments like nifedipine, nitroglycerin, and doxazosin all help by lessening the contraction of the smooth muscle in the area affected by the piloleiomyomas. Other drugs like gabapentin, pregabalin, and duloxetine can be used to manage the pain caused by the condition.
Injecting botulinum toxin (commonly known as Botox) into the areas affected by the piloleiomyomas can sometimes help with symptoms, but the results from this treatment can vary.
What else can Cutaneous Leiomyomas be?
When determining the cause of skin growths called leiomyomas, doctors have to consider many possible conditions because a single lesion can look like many different things. But when multiple skin leiomyomas, particularly a type called piloleiomyomas, are present, they often have a unique appearance, which makes identification easier.
If a patient mentions that these growths are painful or causing discomfort, doctors will need to consider other possible conditions. These might include the blue rubber bleb nevus, angiolipomas, neuromas, glomus tumors, neurilemmoma, endometrioma, granular cell tumors, and eccrine spiradenomas – a group of disorders that can cause painful skin lesions. Dermatofibromas could also potentially be the cause of the skin growths.
