Published on 19/03/2015 by admin
Filed under Dermatology
Last modified 19/03/2015
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Waseem Bakkour, Loma S. Gardner and Ian Coulson
Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports
Cutaneous leiomyomas are rare benign neoplasms originating from smooth muscle. Three types exist: (1) piloleiomyoma, the most common type, arising from the arrectores pilorum muscle; (2) dartoic myoma or genital leiomyoma, arising from scrotal/labial dartos muscle or smooth muscle of the nipple; and (3) angioleiomyoma, arising from vascular wall muscle. Piloleiomyoma frequently occur as multiple lesions (80%). Multiple leiomyomas can be inherited in an autosomal dominant fashion in association with uterine leiomyoma (Reed syndrome, multiple cutaneous and uterine leiomyomata [MCUL1; OMIM 150800]). Familial multiple leiomyomata can rarely be associated with renal cell cancer (hereditary leiomyomatosis and renal cell cancer [HLRCC; OMIM 605839]). Both familial forms are caused by mutations in the fumarate hydratase gene (coding for an enzyme in the tricarboxylic acid cycle) on 1q42.1, which is hypothesized to act as a tumor suppressor gene through an unknown mechanism. Clinically, cutaneous leiomyomas present as flesh-colored or brownish-red dermal papules or nodules up to 2 cm in diameter, typically distributed on the trunk and extensor surfaces of extremities. They often appear from the second to fourth decade and gradually increase in number and size. Paroxysmal pain, described as stabbing, burning, or pinching, may be triggered by cold or mechanical stimulation and is possibly due to muscle contraction or compression of entrapped nerves. Angioleiomyomas are less frequently symptomatic, whilst genital leiomyomas are asymptomatic.
Symptomatic solitary lesions are best excised. Symptomatic multiple leiomyomas are therapeutically challenging because they involve a large area and recur after excision in 50% of cases. Selective excision of larger painful lesions may be considered, but patients warned of the relatively high chance or recurrence. CO2 laser ablation of symptomatic lesions may be successful. Other therapeutic methods aim to inhibit smooth muscle contraction, and thus pain, by interfering with local tissue mediators, e.g., norepinephrine, epinephrine, and acetylcholine. There are reports of success with oral doxazosin (a selective α1-blocker) 1–4 mg daily, oral nifedipine (calcium channel blocker) 10 mg three times daily, phenoxybenzamine (non-selective α-blocker) 10 mg twice daily, topical 9% hyoscine hydrobromide (anticholinergic), and oral glyceryl trinitrate (nitroglycerin) 0.8–1.6 mg as needed. Analgesics that target neuropathic pain, e.g., oral gabapentin 300 mg three times daily, have been beneficial. Potential triggers should be avoided.
Women, particularly those with a family history, should undergo gynecologic review to exclude possible uterine involvement (‘fibroids’). Menorrhagia may necessitate hysterectomy, and leiomyosarcoma, although rare, should be excluded. Potential familial forms require referral to a clinical geneticist with informed consent for mutational analysis of the fumarate hydratase gene. Individuals felt to have HLRCC will require renal ultrasound surveillance to detect the development of renal tumors.
Biopsy
Biochemical assay of fumarate hydratase – for low/absent activity
Genetic analysis – for fumarate hydratase gene mutations
Holst VA, Junkins-Hopkins JM, Elenitas R. J Am Acad Dermatol 2002; 46: 477–90.
Treatment of Skin Disease Comprehensive Therapeutic Strategies 4e
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