Grouped asymptomatic papulonodular lesions over the thigh

A male in his early 20s presented with asymptomatic swellings in the right thigh for 4-5 years.e lesions were non-tender and non-progressive.e patient's past and family histories were non-contributory.On clinical examination, multiple skin colored to hyperpigmented, soft to firm, and painless papules and nodules were distributed on the medial aspect of the right thigh in a segmental pattern [Figure 1a].e lesion showed "button-holing" on digital invagination.e regional lymph nodes were not palpable.ere were no hyperpigmented macules, no soft papules on the face, flexural freckling, bone tenderness or ocular/oral lesions.Dermatoscopy (Dermlite DL4, 3 Gen, CA, USA, Polarized X10) revealed brown pigmentary lines, a peripheral halo of brown pigmentation, and a fingerprint-like pattern [Figure 1b].Ultrasonography revealed hypoechoic masses, and histopathology from a skin-colored papule (Hematoxylin & Eosin) showed a circumscribed, unencapsulated spindle cell tumor composed of haphazardly arranged spindle cells with elongated, plump nuclei, fine chromatin, inconspicuous nucleoli, and moderate eosinophilia to partial vacuolation in a collagenous stroma [Figure 2a-b].e underlying adnexal gland and dermis were unremarkable.No nuclear atypia was seen.Further special staining and immunohistochemistry (IHC) revealed S100 positivity [Figure 2c] and clusture of differentiation (CD) 34 positivity [Figure 2d].Slit lamp examination was reported to be normal.