Indian Journal of Dermatology
ORIGINAL ARTICLE
Year
: 2010  |  Volume : 55  |  Issue : 4  |  Page : 337--341

Leiomyoma cutis: A clinicopathological series of 37 cases


Purnima Malhotra1, Harpreet Walia1, Avninder Singh1, V Ramesh2,  
1 Institute of Pathology, ICMR, Safdarjung Hospital Campus, New Delhi, India
2 Department of Dermatology, Safdarjung Hospital, New Delhi, India

Correspondence Address:
Avninder Singh
213-B Sukhdev Vihar, New Delhi 110025
India

Abstract

Background: Cutaneous leiomyomas are benign smooth muscle tumors that comprise three distinct types such as piloleimyoma, angioleiomyoma, and genital leiomyoma. Aim: The objective of this study was to report a series of cases seen in last 8 years in a tertiary care hospital in north India and to discuss their clinicopathologic findings. Material and Methods: Paraffin-embedded blocks of cases reported as cutaneous leiomyoma from 1999 to 2007 were retrieved from the Institute of Pathology, New Delhi, and their clinical parameters were noted. Their histopathological features were reviewed on hematoxylin-eosin stained slides. Immunohistochemistry was performed where necessary. Results: Twenty-seven cases of piloleiomyoma, three cases of angioleiomyoma, five breast leiomyomas, and two scrotal leiomyomas were seen in patients ranging from 21 to 65 years of age, with an average of 38.2 years at presentation. There was a male predominance with 26 males and 11 females (M:F = 2.2:1). Solitary lesions (n = 21) were more common than multiple ( n = 16). The trunk and upper limbs were involved most commonly, comprising 23 of 37 (62.2%) cases. This was followed by lower limb, face, breast, and scrotum. Conclusion: Cutaneous leiomyomas are rare lesions and form an important clinical differential diagnosis of painful papulonodules. These must be biopsied in order to differentiate them from other spindle cell lesions.



How to cite this article:
Malhotra P, Walia H, Singh A, Ramesh V. Leiomyoma cutis: A clinicopathological series of 37 cases.Indian J Dermatol 2010;55:337-341


How to cite this URL:
Malhotra P, Walia H, Singh A, Ramesh V. Leiomyoma cutis: A clinicopathological series of 37 cases. Indian J Dermatol [serial online] 2010 [cited 2019 Dec 13 ];55:337-341
Available from: http://www.e-ijd.org/text.asp?2010/55/4/337/74535


Full Text

 Introduction



Leiomyomas are benign soft tissue neoplasms that arise from smooth muscle. They can develop wherever smooth muscle is present. Skin is the second commonest location for leiomyoma after uterus which accounts for 95% of cases. Cutaneous leiomyomas account for 75% of extra-uterine leiomyomas. [1] Clinicopathologic data on cutaneous leiomyomas, with special reference to pilar leiomyomas, are scant in the recent literature. [2],[3] This study attempts to reexamine this information in the light of current knowledge. This is the first such series from an Indian population.

 Material and Methods



A retrospective study was conducted by the Department of Pathology with contribution of clinical data by the Department of Dermatology at Safdarjang Hospital, New Delhi. Paraffin blocks of 41 cases reported as cutaneous leiomyoma from 1999 to 2007 were retrieved from the histopathology records of Institute of Pathology, New Delhi. Clinical information and follow-up data were recorded where available. Histopathology was reviewed on hematoxylin and eosin-stained sections with special reference to infiltration, cytologic atypia, and mitotic activity. The presence of nerve fibers and inflammatory cells including mast cells was also noted. All biopsies were reviewed independently by two pathologists and a consensus in diagnosis was reached. All discrepant cases with a differential on light microscopy of nerve sheath or fibrohistiocytic tumors were subjected to Mason-trichome and smooth muscle actin (SMA) staining (11/41). Four cases lacking definite evidence of smooth muscle differentiation were excluded from the study (two fibrous histiocytomas, one keloid, and one neurofibroma).

 Results



Clinical features

Twenty seven cases of piloleiomyoma, three cases of angioleiomyoma, five breast leiomyomas, and two scrotal leiomyomas were seen in patients ranging from 21 to 65 years of age, with an average of 38.2 years at presentation. There was a male predominance with 26 males and 11 females (M:F = 2.2:1). Solitary (n = 21) lesions were more common than multiple (n = 16). A large majority (72.2%) of patients presented because of pain in the lesion. The duration between the appearance of the lesions and consultation was wide and ranged from 1 month to 25 years. The trunk and upper limbs were involved most commonly [Figure 1], comprising 23 of 37 (62.2%) cases. This was followed by lower limb, face, breast, and scrotum that showed approximately equal case distribution [Table 1]. The clinical appearance ranged from nodular (n = 12), papulonodular (n = 9), and plaques (n = 8) to papular (n = 6). One scrotal nodule was pedunculated while another lesion on the face of a young male presented with acneiform distribution [Figure 2]. A large majority of solitary lesions presented with clinical diagnoses of leiomyoma, dermatofibroma, and schwannoma. Two tumors were recurrent, one being solitary and the other a case of multiple chest wall piloleiomyomas. General physical and systemic examination was unremarkable in all patients. Family history of similar lesions was not obtained in any patient at the time of presentation.{Table 1}{Figure 1}{Figure 2}

Histologic findings

Piloleiomyomas and genital leiomyomas exhibited similar histopathological appearance. All tumors fulfilled the classical histological criteria for leiomyoma, namely, interlacing fascicles of spindle-shaped cells showing moderate amount of fibrillary eosinophilic cytoplasm and blunt-ended cigar-shaped nuclei.

The tumors were centered on reticular dermis with four cases showing extension to papillary dermis [Table 2]. These lesions abutted the epidermis, producing flattening of rete ridges overlying the lesion. Tumor cells were arranged in partly circumscribed, unencapsulated interlacing bundles of smooth muscle fibers admixed with collagen [Figure 3]. Prominent arrector pili were noted in the superficial dermis, distinct from the lesion in one case [Figure 4]. Extension into subcutis could not be assessed, as a majority of the biopsies did not extend beyond the dermal-subcutaneous junction. Tumor cells showed eosinophilic cytoplasm, and plump, blunt-ended vesicular nuclei with inconspicuous nucleoli. A moderate degree of anisonucleosis was noted in five cases [Figure 5]. The pleomorphic cells comprised not more than 10% of the total population. Occasional hyperchromatic nuclei were noted. However, no mitotic activity was observed in any of the cases. Intervening fascicles of collagen were noted in 14 cases. An equal number of cases showed the presence of a mild perivascular infiltrate composed of lymphocytes [Figure 6]. Occasionally, mast cells were noted (four cases) within this infiltrate. Nerve fibers were conspicuous adjacent to the lesion only in angioleiomyomas (3/3). Epidermal basal cell hyperpigmentation was uniformly noted in a majority of cases (78.4%). Mild epidermal hyperplasia with an elongation of rete ridges was also an accompanying consistent feature. Three cases showed the presence of extracellular melanin in papillary dermis. The angioleiomyomas were all of the cavernous type and showed the presence of multiple nerve twigs adjacent to the lesion. Strong diffuse immunohistochemical staining for SMA was noted in 7/7 cases included in the study [Figure 7].{Table 2}{Figure 3}{Figure 4}{Figure 5}{Figure 6}{Figure 7}

 Discussion



Cutaneous leiomyomas comprise approximately 5% of all leiomyomas. [1] Three distinct types of cutaneous leiomyomas such as piloleiomyomas, angioleiomyomas, and genital leiomyomas are described. This classification hinges on the origin of the smooth muscle tumor and corresponds to the histologic or anatomic site where the leiomyomas are found. Piloleiomyomas are believed to arise from the arrector pili muscle of the pilosebaceous unit, whereas angioleiomyomas originate from smooth muscle (tunica media) within the walls of arteries and veins. Leiomyomas derived from the dartos muscle of the scrotum and the labia majora, as well as those derived from the erectile muscle of the nipple, are classified under genital leiomyomas. Tumors in each classification have distinct clinical and/or histologic characteristics.

Cutaneous leiomyomas are more common in adults than in children. However, isolated reports of cutaneous leiomyomas in children exist, including a solitary cutaneous leiomyoma on the heel of a neonate at birth. [4] Multiple piloleiomyomas are generally described in those aged 10-30 years, whereas solitary piloleiomyomas usually appear later. In contrast to previous data, mean age at presentation for solitary leiomyoma was lower (38.9 years) as compared to multiple (43.8 years) leiomyomas. Angioleiomyomas most often occur in those aged 20-60 years, although some investigators report a narrower window of increased incidence in those aged 20-40 years. Genital leiomyomas are rare; therefore, an age predilection is not generally mentioned. The numbers in these groups were too small to comment on age distribution. That leiomyomas do not demonstrate predilection for either sex is evident in the conflicting results from various studies. [2] A slight male predominance was noted in solitary lesions (13:8) and when all lesions were considered as a group (21:15). However, the ratio skewed in favor of females for multiple lesions (8:7). The frequency of solitary lesions was higher than multiple in the present study. This may reflect the bias introduced by retrospective selection of cases from histopathology records. Solitary lesions generate a longer list of differential diagnoses, prompting biopsy. The clinical differential diagnosis includes angiolipoma, glomus tumor, eccrine spiradenoma, neurofibroma, nevus, and lipoma.

The distribution of multiple lesions was variable. Most commonly, grouped distribution was noted. Linear, segmental, and zosteriform variants have been described. Besides zosteriform lesions which follow a dermatome, lesions following Blaschko's lines of fetal development have been described. [5] This suggests genetic mosaicism and is thought to represent a clinical expression of a genetically programmed clone of altered cells, perhaps first expressed during embryogenesis.

The segmental manifestations are associated with autosomal dominant disorders and have been subdivided into two categories. Type 1 is heterozygous for a postzygotic new mutation and has a clinical picture similar to that in a segmental phenotype without mutation. Type 2 results from the loss of the corresponding wild-type allele occurring in a heterozygous embryo and reflects either homozygosity or hemizygosity for the underlying mutation, giving rise to pronounced segmental lesions that are superimposed on the ordinary non-segmental phenotype. The pathogenesis of pain associated with these lesions is unresolved. Some authors have suggested that pain could result from local pressure by the tumor on cutaneous nerves. [6] Others have hypothesized that muscle contraction may be central to the induction of pain. [7] The high frequency (72.2%) of patients complaining of pain is unexplained as perilesional nerve fibers were conspicuously absent in all piloleiomyomas. The prominence of nerve fibers in angioleiomyomas is well described. [8] Although a few cases 4/36 (11.1%) demonstrated focal nuclear hyperchromasia and pleomorphism, mitotic activity was notably absent in all cases. This finding correlates with the original diagnostic criteria for cutaneous leiomyoma but contrasts with the data of Raj et al,[2] where 28.3% of tumors were mitotically active. Symplastic leiomyomas akin to the uterine counterparts have been described in the skin. [9] However, cytological atypia was not significant for such categorization. Epidermal changes were consistently noted in a fair number of cases but were not prominent. Although theoretically the list of differential diagnoses is long, the use of Masson trichome and desmin stains excludes most possibilities. Leiomyosarcoma is usually solitary and located on the lower extremity. However, increased cellularity, diffuse nuclear atypia, and ≥ 2 mitoses/10 hpf are essential for diagnosis. Smooth muscle hamartoma shows variably oriented, discrete bundles of smooth muscles closely associated with hair follicles.

Uterine smooth muscle tumors have been demonstrated to have estrogen receptor and progesterone receptor immunoreactivity. As a corollary, gonadotropin-releasing hormone analog therapy is useful in treating uterine smooth muscle tumors. However, no significant immunoreactivity for these receptors was noted in 15 cutaneous leiomyomas by McGinley [10] and recently by Sen et al. [11] These results point to a difference in the pathogenesis of uterine and extra-uterine tumors.

The arrector pili muscle, from which piloleiomyomas originate, attaches proximally to the hair follicle and distally to multiple attachment points within the papillary and reticular dermis, as well as to the basement membrane. Piloleiomyomas can emerge from each of these various points of insertion and occur as multiple tumors. Although no significant histopathologic difference was noted between solitary and multiple tumors, the pathogenesis of multiple leiomyomas is unique. Multiple lesions can be inherited as an autosomal-dominant trait with variable penetrance (Reed's syndrome, [12] or they can occur sporadically. While the skin tumors are relatively uncommon and benign, women of affected families often develop uterine fibroids with associated infertility, pain, and bleeding. In addition, a subset of these families harbors a predisposition to papillary renal cell carcinoma. The predisposition gene for Reed's syndrome has been localized to chromosome 1q42.3-43 and the gene encoding fumarate hydratase. [13] Appropriate screening measures for associated disorders are mandatory.

Pain associated with a solitary leiomyoma on the back lesions was distressing enough to interfere with sleep. Surgical excision with or without skin grafting is the treatment of choice in painful solitary and multiple cutaneous leiomyomas, if a few lesions are present. However, recurrence is frequent with multiple lesions (50%). [1] Although complete follow-up data were not available, recurrence was noted in only two patients in our study. A number of pharmacologic treatment modalities have been employed for patients with painful multiple lesions involving large areas of the body. These include nifedipine, oral nitroglycerine, and oral alpha-1 adrenoceptor antagonist doxazosin. Cryotherapy and electrocoagulation have been attempted. [3] However, satisfactory results have been reported only with CO 2 laser ablation therapy. [14]

 Conclusion



Cutaneous leiomyomas are rare lesions and there is limited literature on its clinicopathologic features. These form an important clinical differential diagnosis of painful papulonodules and must be biopsied in order to differentiate them from spindle cell lesions like dermatofibroma and neurofibroma and myofibroblastic lesions like nodular fasciitis, fibromyoma, and smooth muscle hamartoma. Despite variable clinical manifestations, majority of the lesions show a favorable course and complete excision appears to provide adequate treatment.

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