Cutaneous leiomyomas, also known as piloleiomyomas, are benign uncommon smooth muscle tumors that arise from the arrector pili muscle, which is in charge of hair follicle piloerection. Piloerection, or “goose bumps,” is an involuntary mechanism that can occur as a result of cold exposure or a range of emotional states (eg, fear, pleasure).
Hereditary leiomyomatosis and renal cell cancer is an autosomal dominant cancer condition in which cutaneous leiomyomas can occur randomly or in large numbers. The discovery in 2001 of a link between cutaneous leiomyomas, uterine leiomyomas in women, and an aggressive form of renal cell cancer (RCC) emphasizes the importance of accurate dermatologic diagnosis of CL so that patients and at-risk relatives can receive appropriate cancer screening and counseling.
The co-occurrence of uterine leiomyoma and cutaneous leiomyomas was known under several different eponyms prior to the discovery of the association with renal cell cancer (RCC), including Reed syndrome, multiple cutaneous leiomyomas (MCL), and multiple cutaneous and uterine leiomyomatosis syndrome (MCUL1), leading to potential confusion regarding the associated cancer risk. All of these diseases are now known to be related with mutations in the fumarate hydratase gene (FH)
Cutaneous leiomyomas are hard, red or reddish-brown nodules that range in size from 3 mm to 1 cm in diameter. Small lesions may appear as thin, slightly elevated papules, whereas bigger nodules may be exophytic and protrude significantly from adjacent lesions. Isolated leiomyomas of the scrotum (dartos muscle), vulva, or nipple have been reported on rare occasions (areolar smooth muscle). Leiomyomas arising from genital skin, unlike piloleiomyoma, are frequently asymptomatic.
Clinical diagnosis — When a patient presents with single or several papules or nodules on the trunk or extremities that are often painful to the touch, cutaneous leiomyoma is suspected. A history of episodic pain in response to cold, rubbing, or pressure is common.
Multiple cutaneous leiomyomas should be considered a red flag for inherited leiomyomatosis and renal cell carcinoma (HLRCC).
Biopsy — To confirm the diagnosis of cutaneous leiomyoma, a skin biopsy is required. The skin tissue obtained from a punch biopsy is usually sufficient for pathologic diagnosis.
Genetic testing — The presence of a germline mutation in the FH gene is required for a conclusive diagnosis of HLRCC. Individuals who appear with clinical signs of HLRCC or who have a family history of HLRCC should be offered genetic testing.
Dermatologists, gynecologists, and urologic oncologists collaborate to treat patients with hereditary leiomyomatosis and renal cell carcinoma (HLRCC). The following are important aspects of management:
- In individuals with many painful cutaneous leiomyomas, pain management is important.
- Consultation with a gynecologist on a regular basis to check for the presence and severity of uterine leiomyomas.
- Renal cancer surveillance
Patients with a family history of HLRCC should seek genetic counseling to identify asymptomatic at-risk relatives and begin surveillance for renal cell carcinoma (RCC) at a young age.
Treatment of cutaneous leiomyomas:
Isolated lesions — For cutaneous leiomyomas that are isolated or few in number, surgical excision is the therapy of choice. Because intralesional injection often exacerbates pain, local anesthetic should be used with caution.
Complete excision of segmental or other substantial areas of cutaneous leiomyoma involvement in the HLRCC situation may result in extensive surgical scars that are visually undesirable. Furthermore, patients with numerous lesions have been observed to have a 50% recurrence rate.
Multiple clustered or widespread lesions — Several ablative, topical, or systemic treatments have been tried for individuals with multiple symptomatic cutaneous leiomyomas for whom surgery is not a viable choice due to location, burden of disease, or cosmetic consequence.
However, there is only a single case report and one tiny randomized trial to back up their effectiveness.
Fumarate hydratase (FH) mutation carriers have a 15 to 20% lifetime risk of developing kidney cancer. Between the ages of 10 and 20, FH carriers have a 1 to 2% chance of developing renal cell carcinoma (RCC), which increases as they get older. Even though the initial tumor is modest, these kidney cancers are aggressive, with rapid nodal and distant dissemination.
Written by: Lama Altamimi, medical intern