An 18-year-old man was seen for an asymptomatic cerebriform mass on the right hip that had grown progressively over the preceding 8 years. Physical examination revealed a unilateral 30-cm lesion with a zosteriform distribution, consisting of irregular, skin-colored nodules that were soft on palpation (Fig. 1). Histology showed multiple aggregates of mature adipocytes that were located in the reticular dermis but spared the papillary dermis and epidermis.

Figure 1

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Nevus lipomatosus cutaneous superficialis (NLCS) is a rare hamartomatous anomaly, characterized histologically by the presence of ectopic adipose tissue throughout the papillary dermis. Lesions usually appear during the first 3 decades of life, and are primarily located on the pelvic girdle, buttocks, or lumbar region.

The lesions are slow-growing, with a smooth or cerebriform surface, but can reach a large size if left untreated. Several pathogenic mechanisms have been proposed for NLCS, including adipose metaplasia in the context of degenerative changes of the dermal connective tissue, alterations in adipose tissue development, and growth from cells in the walls of dermal vessels.