Bullous aplasia cutis.

Abstract

Bullous aplasia cutis (BAC) is a well defined clinical entity, described for the first time in 1948 by Yudkin (3); in the literature about twenty cases were reported. It is clinically characterized by blister-like lesions that gradually hesitate in scar without going through an erosive or crusted phase. From a nosologic point of view BAC is often identified with membranous aplasia cutis, i.e. the smaller, 1-3 cm in diameter, rounded, not ulcerated but covered by atrophic epidermis, bright variety of aplasia cutis, clinically opposed to the more extensive, starry, ulcerated form of aplasia cutis. According to others, BAC has its own individuality consisting in the blister-like or cyst-like appearance; it is soft at palpation, can be depressed and only secondarily turns into a scar. Even more characteristic is its histologic appearance according to Colon-Fontanez et Al. (1): it would have no scar appearance at the beginning, but due to the integrity of the epidermis, the remarkable edema of the superficial dermis and the presence of small cystic cavities bounded by stellate cells, it is reminiscent of the histological findings of meningocele and encephalocele. This characteristic histological finding and the presence in some cases (2) of a collar of hypertrichotic hairs around the cyst-like lesion, led to hypothesize that BAC is actually linked to a defect in neural tube closure.