Recurrent nevi: report of three cases with dermatoscopic-dermatopathologic correlation

A 40-year-old patient presented with a papule on the calf with irregular brown pigmentation (Figure 1). On dermatoscopy the lesion was composed of segmental radial lines and structureless zones. Discrete reticular lines were also seen but they were also present in the surrounding normal skin. The pigmentation did not extend towards the edge of the visible scar. Disregarding the clinical history of a previous surgery of a nevus the differential diagnosis based solely on the dermatoscopic presentation includes recurrent melanoma, basal cell carcinoma and recurrent nevus. Histopathologically one can spot inconspicuous dermal nests of melanocytes on site and heavily pigmented melanocytes at the dermoepidermal junction on the other. The epidermal melanocytes are arranged as single cells of which some can be found in higher levels of the epidermis including the stratum corneum, resembling melanoma in situ. The fact that this area is present above a scar of an otherwise inconspicuous “superficial and deep” congenital nevus, as well as the patient history of a previous shave biopsy, led to the diagnosis of a recurrent nevus.