Chapter 171: Dysplastic Nevus and Spitz Nevus

PATIENT STORY

A 44-year-old man presents with concern over a mole on his back that his wife says is growing larger and more variable in color. The edges are irregular, and the color almost appears to be "leaking" into the surrounding skin. He reports no symptoms related to this lesion. On physical exam, the nevus is 9 mm in diameter with asymmetry and variations in color and an irregular border (Figure 171-1). A full-body skin exam demonstrated no other suspicious lesions. Dermoscopy showed an irregular network with multiple asymmetrically placed dots off the network (Figure 171-2). A saucerization (deep shave) was performed with a DermaBlade taking 2-mm margins of clinically normal skin (Figure 171-3). Pathology showed a completely excised compound dysplastic nevus with no signs of malignancy. No further treatment was needed except yearly skin exams to monitor for melanoma.

INTRODUCTION

Dysplastic nevi (DN) (atypical moles) and Spitz nevi are irregular-appearing nevi with clinical and histologic definitions that are controversial and still evolving. Both DN and Spitz nevi have clinical, dermoscopic, and histologic features that overlap with melanoma. Patients with multiple DN or an atypical Spitz nevus have an increased risk for melanoma.¹ The presence of multiple DN is a marker for increased melanoma risk just as red hair is, and, analogously, cutting off the red hair or cutting out all the DN does not change that risk of melanoma. DN are not precursor lesions of melanoma; they are markers for an increased risk of melanoma. The problem with DN is that any one lesion that is suspicious for melanoma must be biopsied to avoid missing melanoma, not to prevent melanoma from occurring in that nevus in the future.

Spitz nevi (Figures 171-4 and 171-5) are uncommon solitary pink to black dome-shaped papules that usually appear in the first 2 decades of life. They have features histologically similar to melanoma, and some may in fact be spitzoid melanomas. Lesions suspected to be Spitz nevi should be biopsied for histopathologic diagnosis, and in ...