a 43-year - old female patient presented with clusters of multiple firm , painful , brownish papules and nodules covering the entire lower left limb and extending up to the left flank in a zosteriform arrangement ( figure 1a , 1b ) . one papule revealed a featureless central hypopigmented area with a delicate peripheral network ( figure 1c , 1e ) . in each of the remaining four lesions , we observed the presence of a circular and/or elongated hyperpigmented structure that lacked a well - defined dermoscopic pattern within the hypopigmented central area ( figure 1d , 1f ) . on hematoxylin and eosin histopathologic examination of two excised lesions ( figure 2a  corresponding to figures 1c , 1e ; figure 2b  corresponding to figure 1d , 1f ) , a benign mesenchymal neoplasia was observed , consisting of interlacing bundles of smooth muscle cells intermingled with various amounts of collagen bundles in accordance with the diagnosis of cutaneous leiomyoma . furthermore , in figure 2b , the elongation of the rete ridges associated with focal compact hyperkeratosis was also noted . they can be classified into three types , those derived from the erector pili muscle of hair follicles ( piloleiomyomas ) ; those originating from the vascular smooth muscle ( angioleiomyomas ) ; and those arising from the smooth muscle of genital skin ( dartoic leiomyomas ) . cutaneous leiomyomas typically present in the second to fourth decade of life as skin - colored or brown - reddish grouped papules or nodules localized on the trunk and limbs . these tumors are painful on exposure to cold and trauma ; pain could result from local pressure by the tumor on cutaneous nerves . the main differential diagnosis consists of other dermal nodular lesions like dermatofibroma , eruptive syringoma , angiolipoma , neurilemoma , endometrioma , leiomyosarcoma , glomus tumor , eccrine spiradenoma , lipoma and blue nevus . although piloleiomyoma is frequently pigmented , it does not frequently enter a clinician s differential diagnosis when evaluating cutaneous pigmented lesions . moreover , we are not aware of previous dermoscopic descriptions of piloleiomyoma in the literature . dermoscopically , piloleiomyoma presents similar features of dermatofibroma with the central featureless hypopigmented area and a delicate peripheral network 5,6,7 ] . in addition , we observed the presence of oval and/or elongated hyperpigmented structures within the central area that , to the best of our knowledge , have not been previously described . we suggest that it may be explained by the presence of focal compact hyperkeratosis that generates a dermoscopic feature similar to the pseudofollicular openings and pseudostreaks seen in pigmented seborrheic keratosis . further observations are necessary to determine if this feature is a characteristic finding in piloleiomyoma . in vivo
piloleiomyoma can manifest itself as a pigmented lesion and part of the differential diagnosis with other pigmented skin lesions . however , we are not aware of previous descriptions in the literature of the dermoscopic features of piloleiomyoma . 
 this article describes the dermoscopic findings observed in a patient with multiple piloleiomyomas . on dermoscopic evaluation 
 , piloleiomyoma has characteristics similar to dermatofibroma with a thin peripheral pigmented network and central scar - like area . 
 some of the piloleiomyomas analyzed in this patient also presented with hyperpigmented circular and/or elongated structures within the central hypopigmented area .