Lichen planus-like dermatosis with Blaschko line distribution: a case report.

The authors describe the case of a healthy 46-year-old woman with a unilateral linear papular band on the left side of the trunk that followed the lines of Blaschko from the lower back extending to the left anterior side of her abdomen. The lesions were flat-topped, slightly elevated, violaceous, agglomerated lichenoid papules. The biopsy specimen demonstrated the typical histology of lichen planus. A working diagnosis of linear lichen planus was confirmed. Because congenital and/or nevoid skin disorders in a blaschkolinear distribution may have a delayed onset after birth, these lesions must be differentiated from acquired dermatoses following the lines of Blaschko. This distinction should be made in cases with isolated lesions, such as the case presented here.