Case report Acardiac twin: a misdiagnosed, mismanaged case Neslihan Carda Sec ¸kin * , Nilgu ¨n O ¨ ztu ¨rk Turhan, S ¸u ¨kran Kopal, I ˙ lknur I ˙ nego ¨l Department of Obstetrics and Gynecology, Fatih University School of Medicine, Ankara, Turkey Received in revised form 22 April 2002; accepted 1 August 2002 Abstract Acardiac twins are usually diagnosed during the antenatal period and almost invariably cause complications to the other fetus. In this case, an acardiac twin pregnancy was misdiagnosed antenatally as a degenerated myoma but ended with delivery of a healthy baby. # 2002 Published by Elsevier Science Ireland Ltd. Keywords: Acardiac twin; Pump twin 1. Introduction Acardiac anomaly is a rare complication of mono-zygotic multiple pregnancies and is usually diagnosed during the antenatal period [1]. We report a case which was misdiag- nosed and mismanaged antenatally as a degenerated myoma. 2. Case report A 23-year-old Philipino woman, gravida 2, para 0, abortus 1, was referred at 19 weeks. Physical examination and laboratory tests were unremarkable. Ultrasonographic bio- metry corresponded to 17 þ 3 weeks of gestation; amniotic fluid volume was normal. There was a 24 mm  18 mm solid, partially calcificated round extra amniotic mass close to the inferior placental edge and protruding into the amniotic cavity. At 29 weeks, the mass had enlarged to 54 mm  44 mm. Fetal biometry showed linear growth and amniotic fluid volume was nor- mal. The mass was presumed to be a submucous myoma uteri. At 34 weeks, the patient was hospitalized for pre-term labor and treated with tocolysis. She was discharged after 3 days. At 40 weeks, the mass was 90 mm  80 mm in dia- meter, there was no problem with the fetus and the amniotic volume was normal. Doppler ultrasound examination of the mass showed no blood flow. At 41 weeks, the patient gave birth to a female baby weighing 3885 g, length 51 cm. New- born examination was normal. Before placental separation, a mass approximately 100 mm  120 mm delivered. It was almost entirely covered with hairy scalp like tissue with vulva and glutea like formations. It was attached to the placenta with a 15 cm umbilical cord covered with membranes (Fig. 1). Pathological examination revealed epidermis, calcifica- tions, fat tissues and hair follicles on the sections. The umbilical cord had a single artery and a vein, and placental membranes were thickened. The gross appearance of the placenta was normal. The pathological diagnosis was ‘‘acar- diac fetus’’. 3. Discussion Acardiac twin complicates approximately 1% of mono- zygotic twins and 1/35,000 births, and is associated with placental vascular anastomoses between the affected fetus and its co-twin. The affected fetus is sustained by the normal co-twin (pump twin) [1,2]. The pathophysiology is referred to as twin reversed arterial perfusion (TRAP) and has been demonstrated in utero by doppler sonography [3,4]. The TRAP sequence is a key diagnostic element for antenatal ultrasonographic examination and is the cause of the pump twin’s complications, growth retardation, cardiomegaly and cardiac failure. High renal perfusion in the pump twin may cause polyhydramnios and pre-term delivery [2,3]. In our case, the diagnosis was not considered because the mass was unexpectedly small. Some of the cases [1] are extremely large, 4000 g, and until this case we had assumed that an acardiac twin was always at least the size of its co-fetus. The mass was located like a submucous myoma and no blood flow was detected inside it. The pre-term labor was consi- dered to be the consequence of degeneration of the myoma. European Journal of Obstetrics & Gynecology and Reproductive Biology 107 (2003) 212–213 * Corresponding author. Present address: C ¸ayyolu, Mavis ¸ehir 85, No. 99, 06530 Ankara, Turkey. Tel.: þ90-312-2126262; fax: þ90-312-2213276. E-mail address: nesli4@hotmail.com (N.C. Sec ¸kin). 0301-2115/02/$ – see front matter # 2002 Published by Elsevier Science Ireland Ltd. PII:S0301-2115(02)00306-8