Answer of Dermatopathology Case 48

Immunohistochemistry: Smooth Muscle Actin

Cutaneous Leiomyoma (Piloleiomyoma)

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Abstract:

Cutaneous smooth muscle neoplasms: clinical features, histologic findings, and treatment options.J Am Acad Dermatol. 2002 Apr;46(4):477-90; quiz, 491-4.

Cutaneous smooth muscle is present in 3 separate locations: arrector pili muscles, blood vessel walls, and genital/areolar skin. Benign or malignant smooth muscle neoplasms may arise from each of these locations. This review discusses the pathogenesis, clinical manifestations, histologic findings, prognosis, treatment options, and controversial areas of cutaneous smooth muscle neoplasms. ( J Am Acad Dermatol 2002;46:477-90.) Learning objective: At the completion of this learning activity, participants should be able to discuss the pathogenesis, clinical manifestations, histologic findings, prognosis, and treatment options of cutaneous smooth muscle neoplasms.

Case for diagnosis: (unilateral multiple piloleiomyoma). An Bras Dermatol.2009 Mar-Apr;84(2):197-9.

Piloleiomyoma is a benign neoplasm arising from the erector pilorum muscle in the skin. It occurs in young adults of both genders. Lesions can be single or multiple and more frequently involve extremities. Pain may occur spontaneously or after physical stimulation. We describe a case of unilateral multiple piloleiomyoma in a young woman, complaining of itching lesions.

Bilateral segmental leiomyomas: a case report and review of the literature. Cutis.2008 Jul;82(1):33-6.

Cutaneous leiomyomas are benign tumors of smooth muscles. We report a rare case of bilateral segmental leiomyomas in an 81-year-old man. We also provide a concise review of the literature on leiomyomas, their associations, and genetic defects of multiple cutaneous and uterine leiomyomatosis (MCUL) and hereditary leiomyomatosis and renal cell cancer (HLRCC) syndromes.

Clinical and molecular genetic aspects of hereditary multiple cutaneous leiomyomatosis.Eur J Dermatol.2009 Nov-Dec;19(6):545-51. Epub 2009 Jul 10.
Multiple cutaneous and uterine leiomyomatosis syndrome (MCUL; OMIM 150800) is an autosomal dominantly inherited tumor predisposition disorder, characterized by leiomyomas of the skin and uterus. When associated with kidney cancer, this syndrome is known as hereditary leiomyomatosis and renal cell cancer (HLRCC; OMIM 605839). All disease variants result from heterozygous mutations in the fumarate hydratase (FH) gene. Cutaneous leiomyoma can easily be recognized and confirmed by histological examination. Recognition of these benign skin tumors can lead to the diagnosis of MCUL or HLRCC. Timely diagnosis is crucial for offering affected individuals and families potentially life-saving regular prophylactic screening examinations for renal tumors. Here we provide an overview of clinical and genetic features of this complex tumor syndrome and discuss patient management and current therapeutic strategies.

Cutaneous pilar leiomyoma: clinicopathologic analysis of 53 lesions in 45 patients. Am J Dermatopathol.1997 Feb;19(1):2-9.
As cutaneous pilar leiomyomas have received little attention in the recent literature, 53 lesions from 45 patients were studied to analyze their clinicopathologic features. There was an equal distribution between both sexes; most patients were adults with a wide age distribution. Both multiple (29 lesions from 21 patients) and solitary tumors (18 patients) were included. Lesions on the extremity (29 tumors) were common in both groups, whereas truncal tumors (11) were confined largely to patients with multiple lesions. In six patients the number of lesions was not specified. The tumors were painful in 17 patients. Three patients had a positive family history of similar lesions. Histologic study revealed ill-defined bundles of well-differentiated smooth muscle cells in the reticular dermis in all cases, although nine lesions had a more nodular pattern. Overlying epidermal hyperplasia was noted in 29 cases (54.7%). Immunohistochemically there appeared to be an increased number of nerve fibers within and surrounding the tumors. Mitotic activity was observed in 15 lesions (28.3%), 13 of which had <1 mitosis per 10 high power fields (HPF); the remaining two lesions had 1-2 mitoses per 10 HPF. Follow-up was available in 10 of these mitotically active tumors and ranged from 9 months to 7 years. There was no recurrence in any of them. We have concluded tentatively that leiomyomas of arrector pili origin may exhibit a low mitotic activity of <1 per 10 HPF and that this does not adversely affect the prognosis for these patients.