Table of Contents
Introduction
Cutaneous leiomyomas are extremely rare, benign smooth muscle tumors. It is classified based on the smooth muscle origin within the tumor. Angioleiomyomas, the most common type of cutaneous leiomyomas, originate from the tunica media of the blood vessels. Piloleiomyomas and vaginal leiomyomas develop in the arrector pili muscle of the hair follicle and smooth muscle in the labia, scrotum, or nipple.
Patients with several cutaneous leiomyomas, or piloleiomyomas, may have an underlying genetic mutation that raises their risk of developing renal cell carcinoma. Both piloleiomyomas and vaginal leiomyomas can cause pain and discomfort. Piloleiomyomas are more common in adults than in children, affect all races equally, and have no gender-specific occurrence. According to research, vaginal leiomyomas are considered to be the most prevalent type, followed by piloleiomyomas.
How Does Cutaneous Leiomyomas Occur?
Piloleiomyomas may occur occasionally or due to an autosomal dominant genetic condition. Reed syndrome, also known as multiple cutaneous and uterine leiomyomatosis (MCUL), is caused by a heterozygous germline mutation in the gene encoding fumarate hydratase (FH), an essential enzyme in the Krebs cycle that aids in the conversion of fumarate to malate. Genetic syndrome-related piloleiomyomas typically manifest earlier in life, with an average lesional onset age of 25 years old (with a range of 10 to 50 years old). The pathophysiology of the association between heterozygous fumarate hydratase deficiency and the development of leiomyomas remains unknown. Still, fumarate hydratase is considered a tumor suppressor to some extent.
Fumarate hydratase (FH) heterozygous germline mutations are present in about 89 percent of patients with multiple cutaneous leiomyomas. Female patients with FH mutations frequently have symptomatic uterine fibroids (more than 90 percent) and piloleiomyomas (85 percent). Compared to non-hereditary uterine leiomyomas, uterine leiomyomas due to FH mutations are typically larger (up to 3.94 inches), more numerous, occur at a younger age, and require hysterectomy. However, the most severe feature of an FH mutation is its association with an aggressive subtype of renal cell carcinoma (type 2 papillary renal cell carcinoma), which develops in around 15 percent of patients.
What Are the Symptoms and Signs of Cutaneous Leiomyomas?
Piloleiomyomas manifest as a single cutaneous nodule or several nodules arranged in a clustered, unidirectional, dermatomal, or dispersed pattern. Two distinct collections in different anatomical regions are standard when numerous piloleiomyomas are present. The nodules might be skin-tone, red, pink, or reddish-brown, varying in size from two (millimeters) mm to 20 mm. Multiple piloleiomyomas exist on the extensor surfaces of limbs and trunks, whereas solitary piloleiomyomas are on the lower extremities.
The primary initial complaint of patients with multiple piloleiomyomas is pain, which can be triggered by pressure, cold, intense emotion, or mild touch, or it can happen on its own. Pain is usually described as sharp, shooting, or aching in nature. Most patients experience these lesions between the ages of 20 and 40. Genital leiomyomas usually form on the genitals, which include the vulva, scrotum, and penis, but they may also develop on the nipple-areolar complex. Usually, the lesions are a single, asymptomatic nodule. They may occasionally show as a pedunculated lesion, leading to misdiagnosis as an acrochordon or a genital wart. Angioleiomyoma is a complex, frequently painful subcutaneous lump on the lower extremities in females between 40 and 60.
What Is the Diagnosis of Cutaneous Leiomyomas?
Physicians can diagnose cutaneous leiomyoma based on history and physical examination, but a biopsy is usually required for a histological evaluation to confirm a probable diagnosis. Genetic leiomyomas and angioleiomyomas typically do not need further investigation beyond a biopsy. Patients with multiple piloleiomyomas may require additional testing because of a significant association with HLRCC or Reed syndrome.
Screening at an early age is essential because patients younger than ten years old have been identified with HLRCC-related renal cell carcinoma. The first screening for fumarate hydratase deficiency in children is recommended between ages 8 and 10. If the results are positive, the child should undergo yearly magnetic resonance imaging (MRI) to check for the emergence of renal cell carcinoma. The same strategy applies to adults with HLRCC who have a positive fumarate hydratase mutation. Patients should have a comprehensive physical and gynecological checkup (if necessary) and dermatological exams twice a year.
What Is the Treatment for Cutaneous Leiomyomas?
The management of symptomatic piloleiomyomas can be challenging for both medical professionals and patients. This is because surgical recurrence is common following intervention, and no effective pharmaceutical treatment options exist. Treatment is determined by the lesions' number, anatomical location, and pain level. Surgical excision is the gold standard treatment for a limited, localized number of piloleiomyomas. The patient should be informed of the considerable risk of local recurrence, which can occur as early as six weeks following removal. Cryosurgery and CO2 lasers are additional ablative therapeutic methods.
Pharmacological therapy may be suitable for patients who are not eligible for surgery (for example, severe, widespread piloleiomyomas or the patient refuses to accept the possibility of recurrence). Medicines, including Nitroglycerin, Nifedipine, and Doxazosin, aim to reduce smooth muscle contractions in the pilosebaceous unit. The following medications may be used to help manage pain caused by the lesions: Duloxetine, Gabapentin, and Pregabalin. Botulinum toxin injections into lesions have produced mixed results in terms of symptom reduction.
Conclusion
Cutaneous leiomyomas are rare lesions that are challenging to diagnose and cure. As a result, they are most effectively handled by a multidisciplinary team that includes the primary care physician, nurse practitioner, dermatologist, plastic surgeon, and pathologist. The recurrence of the lesions is a concern with the treatment. Even though surgery is the best course of action, too much removal of a benign lesion is considered aggressive. Treatments using medications have not always been successful. An appropriate substitute for therapy in asymptomatic patients is observation. All patients require follow-up since these lesions can develop and compress adjacent structures. It is essential to closely monitor people with hereditary lesions because they may be at risk for renal cell carcinoma.
