NEVUS SPILUS
NEVUS SPILUS ICD-10: L81.48
• Light brown pigmented macule varying from a few centimeters to a large area (>15 cm), and many dark-brown small macules (2 to 3 mm) or papules scattered throughout the pigmented background (Fig. 9-8A). The pigment in the macular background may be so faint that it can be recognized only under Wood light (Fig. 9-8B).
• The pathology of the macular pigmented lesion is the same as lentigo simplex, that is, increased numbers of melanocytes, while the flat or raised lesions scattered throughout are either junctional or compound; rarely, these may be dysplastic nevi.
• The lesions are not as common as melanocytic nevi, but are not at all rare. In one series, the nevus spilus was present in 3% of White patients.
• Malignant melanoma very rarely arises in these lesions.
A
B
FIGURE 9-8 • Nevus spilus (A) This dark brown pigmented macule measuring about 10 cm along the long axis is peppered with many small, dark brown to black macules and papules. (B) This is also nevus spilus but the macular background is only slightly pigmented so that it will be revealed only under Wood light. The lesion is peppered with many small dark-brown macules and flat papules.