Dermatoscopy of multiple piloleiomyomas with disseminated and segmental distribution

Clinical examination revealed clustered, firm, reddish-brown papules, fixed to the skin, covering the forehead, cheeks [Figure 1] a and [Figure 1]b, left side of the neck [Figure 1]a, gluteal region (disseminated distribution) and the right scapular region (segmental distribution) [Figure 1]c.{Figure 1} The papules located on the head and neck region dermatoscopically showed whitish clods, scattered and partially clustered throughout the lesion, varying in size and number, with delicate brown reticular lines between them [Figure 2]a and [Figure 2]b. The papules localized on the back mainly showed only brown, reticular, parallel or irregular lines [Figure 2]c and [Figure 2]d.{Figure 2} Two incisional biopsies were performed, one from the jawline and the second from the back. In this type of mosaicism, individuals carrying a germline-dominant mutation that affects all cells of the body acquire a second postyzgotic alteration of the other allele of the same gene, resulting in loss of heterozygosity affecting only a part of the cells. [...]we report a case of type 2 segmental mosaicism of piloleiomyomas, which showed various dermatoscopic presentations at different locations.