Can You Identify This Skin Condition?

A blue-eyed, fair skinned, 30-year-old female has had this lesion on her posterior thigh for the past 15 years. Patient reports mild changes in color and shape over a period of years. It is not painful and does not itch. Past medical history is unremarkable.

(Answer and discussion on next page)

Answer: Nevus Spilus 

Nevus spilus is a benign lesion characterized by multiple dark brown macules distributed throughout a pigmented background.  Rarely malignant melanoma may arise in these lesions.¹

Lentigo maligna and solar lentigo typically occur in sun exposed areas in older persons. Nevus of Ota is a pigmented lesion which is most commonly associated with the first and second branches of the trigeminal nerve.² Café-au-lait macules typically present at birth or early childhood, their pigmentation is usually uniform and only a few shades darker than uninvolved skin.³

Reference

1)    Johnson RA, Wolff K. Fitzpatrick’s color atlas and synopsis of clinical dermatology (5^th ed). McGraw-Hill; 2005.

2)    Hori Y, Takayama O. Circumscribed dermal melanoses. Classification and histologic features. Dermatol Clin. 1988;6:315.

3)    Boyd KP, Gao L, Feng R, et al. Phenotypic variability among café-au-lait macules in neurofibromatosis type 1. L AM Acad Dermatol. 2010;63:440.