Bullous aplasia cutis congenita.

A tense yellow vesicle was noted on the back parietal scalp of a female newborn. This proved to be a bullous variant of aplasia cutis congenita. Only 16 cases of this apparently rare disorder have been previously reported. Histologic evaluation of such lesions reveals a distinct pattern containing fibrovascular stromas, edematous stroma, or both. Identical histologic findings are found in encephaloceles and meningoceles, supporting the recently proposed hypothesis that this variant of aplasia cutis may represent the form fruste of a neural tube closure defect. This disorder should be included in the differential diagnosis of vesicobullous lesions in the neonate. Bullous aplasia cutis congenita is a rare clinical subtype of aplasia cutis congenita with distinctive histologic findings. We present a new case, and summarize the clinical and histologic findings of the 16 cases previously reported in the English-language literature. Bullous or membranous aplasia cutis congenita may represent a form fruste of a neural tube defect.