Segmental pigmentation disorder with block-like hypopigmentation on the abdomen, with midline demarcation superiorly and slight extension past the midline inferiorly.
From: Molho-Pessach V, Schaffer JV. Blaschko lines and other patterns of cutaneous mosaicism. Clin Dermatol 2011; 29:205. Illustration used with the permission of Elsevier Inc. All rights reserved.