A 35-year-old man has a family history of skin cancer and requests a full body examination. His wife is especially concerned about a cluster of moles on his back that have been present for many years. The patient has fair skin and has had ample past sun exposure. Examination reveals multiple pigmented nevi of his trunk and extremities, none overtly suspicious. The area in question is a well-demarcated tan macule interspersed with smaller deeply pigmented macules. Dermatoscopic examination reveals aggregated brown and black globules and a reticulated pigment network.
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Nevus spilus is a sharply marginated café-au-lait macule that contains speckled areas of macular hyperpigmentation. Frequency is equal in men and women, and the condition often presents at birth as a uniform tan lesion. The darker pigmented speckles increase in size and number over time, and some may evolve into papules. Larger lesions may attain a size of 20 cm in diameter.1 Originally believed to have no malignant potential, several recent case reports have documented malignant melanomas arising within these lesions, some with fatal outcome.2,3 Larger lesions are at greatest risk for neoplastic transformation.4 Therefore, periodic examination is prudent, and any suspicious changes warrant biopsy to rule out malignant transformation.
Stephen Schleicher, MD, is an associate professor of medicine at the Commonwealth Medical College in Scranton, Pennsylvania, and an adjunct assistant professor of dermatology at the Perelman School of Medicine at the University of Pennsylvania in Philadelphia.
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- Meguerditchian AN, Cheney RT, Kane 3rd JM. Nevus spilus with synchronous melanomas: case report and literature review. J Cutan Med Surg. 2009;13:96-101.
- Karam SL, Jackson SM. Malignant melanoma arising within nevus spilus. Skinmed. 2012;10:100-102.
- Abecassis S, Spatz A, Cazeneuve C, et al. Melanoma within naevus spilus: 5 cases. Ann Dermatol Venereol. 2006;133:323-328.