Twin reversed arterial perfusion [TRAP] sequence

Herein, we describe three unrelated cases with acardius in which the heart and other parts of the body are formed imperfectly in one of the twins. Clinically, the three cases showed no skull, face or neck, Both upper limbs were absent in case I and II while the right upper limb was absent in case II, Oligodactyly or segmentation of the lower limbs were observed in three cases. Ultrasonography showed an irregularly shaped microcephalic head which looked like a pigeon-head surrounded by an unusual diffuse impression of a banana slice. The facial features were absent. The etiology and pathogenesis of acardius together with the ultrasonographic findings are discussed