Familial Nonmembranous Aplasia Cutis of the Scalp

Abstract

Aplasia cutis of the scalp is often a sporadic condition, but familial occurrences with an autosomal dominant inheritance have been documented. Aplasia cutis of the scalp may be seen in two main clinical variants: oval-shaped membranous aplasia cutis and irregular, larger defects. We report six families in whom more than one member has aplasia cutis of the scalp, all of them with large irregular defects located over the vertex or anterior to the vertex along the sagittal suture. We review previous reports of this entity with clinical pictures and note that in most instances, the defects are of the nonmembranous variant.

Trichoscopy of Focal Alopecia in Children - New Trichoscopic Findings: Hair Bulbs Arranged Radially along Hair-Bearing Margins in Aplasia Cutis Congenita

“…Lesions in these cases have a membranous covering that may be filled with fluid, giving the lesion a bullous appearance. The existence of a hair collar suggests the presence of ectopic neural tissue [19]. Histologic evaluation of the bullous or membranous ACC reveals fibrovascular and/or edematous stroma, similar to the histopathological appearance of encephaloceles or meningoceles [20].…”

“…Within the defective area itself, there are no elastic fibers, no normal blood vessels and no dermal papillae. After several weeks, the epidermis may appear flattened, and there may be a proliferation of fibroblasts within the connective tissue stroma [19,21]. …”

“…The defect may be secondary to vascular disruption or biomechanical stretch. Familial ACC is generally of the nonmembranous type, whereas membranous ACC is usually sporadic [19]. …”

Aplasia cutis congenita: approach to evaluation and management

“…Membranous ACC of the scalp has been proposed to be due to incomplete closure of ectodermal fusion lines . There is often, but not always, a hair collar, which suggests the presence of ectopic neural tissue.…”

Aplasia cutis associated with coarctation of the aorta: could this be an incomplete form of Adams?Oliver syndrome?

“…Some authors conclude that patients with isolated limb defects or nonmembranous ACC of the scalp should be considered to have AOS when these defects are found, even separately, in members of the same family 3,7 . This is supported by the hypothesis of a similar pathogenic mechanism for cardiac malformations, nonmembranous ACC and limb defects.…”