Congenital curvilinear palpable hyperpigmentation.

We report two cases of congenital curvilinear palpable hyperpigmentation on the posterior aspect of bilateral legs in male infants. These lesions appeared shortly after birth and mimicked child abuse with looped cord or postinflammatory hyperpigmentation. Histopathologic features showed lentiginous melanocytic hyperplasia. One of the boys also had severe global developmental delay with abnormal findings from magnetic resonance imaging of the brain. We believe that these lesions represent a new type of congenital hyperpigmentation that we termed "congenital curvilinear palpable hyperpigmentation." Although these lesions do not follow the lines of Blaschko, they may also be associated with neurologic and developmental abnormalities.