A Case Report: Aplasia Cutis Congenita Secondary to Fetus Papyraceus

Abstract

Aplasia cutis congenita (ACC) is a rare
skin condition that presents with absence
of fetal skin at the time of birth. It presents
most commonly with an isolated lesion on
the scalp. Non-scalp lesions usually involve
the trunk and lower extremities and are
often bilateral and symmetrical [1] (Figure
1). Fetus papyraceus (FP) is a known, yet
rare cause of ACC. The incidence of ACC in
association with FP is estimated to be 1 in
12,000 live births [2]. FP is a condition that
occurs in multiple gestations where one fetus
is demised, usually in the second trimester.
The non-viable fetus becomes a mummified,
parchment-like fetus [3]. The cause of ACC
secondary to FP is unknown but theories
have been proposed. The vascular theory
suggests the death of one fetus allows for
passage of thrombogenic agents to the living
twin through placental anastomosis. This,
in turn, activates the coagulation cascade
resulting in disseminated intravascular
coagulation (DIC). DIC results in ischemic
changes to the developing skin and, rarely,
to the underlying tissue [4-8]. Another
proposed mechanism is when one twin
dies it leads to a drastic relaxation of the
vasculature in that twin causing blood to
shunt to the low resistance system leading to
acute hypovolemia in the living twin. This
results in ischemia of the skin and other
organs [5,6,9,10]. The last proposed theory is
disturbance of feto-fetal transfusions [7,10].
This theory states ischemia occurs in both
twins and only one twin can survive with
aplastic scarrin g due to restricted blood
flow [5,11]. As ACC is primarily limited to
the skin, it is not detectable on ultrasound
and is usually diagnosed at time of delivery.
We present a case of symmetric aplasia cutis
congenita secondary to fetus papyraceus.