Bilateral segmental neurofibromatosis with lentiginosis showing a checkerboard pattern

Segmental neurofibromatosis, a subtype of neurofibromatosis type 1, is characterized by neurofibromas and/or café-au-lait spots limited to an area or segment of the body. Checkerboard pattern is a rare type of cutaneous mosaic manifestation, characterized by squares or broad ribbons of affected skin with sharp demarcation at the midline. Herein, we report the case of a patient with bilateral segmental neurofibromatosis with lentiginosis showing a checkerboard pattern. Our patient had multiple hyperpigmented macules on her entire body in a checkerboard pattern since birth. Several cafe-au-lait patches were observed on the left buttock and right axilla. A neurofibroma was incidentally found beneath the cafe-au-lait patch by histological examination, which showed ill-defined spindle cells with elongated nuclei at the deep dermis that stained positive for S-100. Based on the clinical presentation and histopathologic results, the patient was diagnosed with bilateral segmental neurofibromatosis with lentiginosis showing a checkerboard pattern. (Korean J Dermatol 2019;57(6):328∼331).