A 14-month-old Asian boy presented for evaluation of 3 clusters of papules on his torso that had been noted at birth. The lesions were asymptomatic but had recently increased in size and had become erythematous. The patient had been delivered at term after an uncomplicated pregnancy and was otherwise healthy. The family history was unremarkable.
Physical examination revealed 3 groups of skin-colored to pink, slightly firm, papules coalescing into linear plaques on the back and abdomen. The largest lesion measured 0.8×1.5 cm in diameter (Figure 1). The findings of the rest of the physical examination were normal. A biopsy specimen was obtained (Figure 2 and Figure 3).