Radiological Diagnosis

Fetus Papyraceus

Sonogram shows a twin gestation; a small dead compressed fetus with CRL-65mm (corresponding to 12.8±2 week's gestation) and the other viable fetus of 24±2 week's gestation. The viable twin had normal sonomorphometric parameters and no gross congenital anomaly. A single placenta was noted. The fetus papyraceus was stuck to the anterior uterine wall. There was no evidence of a separating membrane and only a single umbilical cord could be recognized.

The patient was advised follow up scans but she did not report for further antenatal visits or ultrasound scans. Three months later the patient presented in labour with symptoms and signs of pregnancy induced hypertension. She delivered a 2.8kg female baby and placenta complete with membranes (spontaneous normal vaginal delivery). There was absorption of the fetus papyraceus and no fetal parts could be identified.

Fetus papyraceus or fetus compressus is a mummified, compressed fetus occurring in association with a viable twin. The fetus undergoes flattening, necrosis and atrophy. It is a rare condition occurring in both monochorionic and dichorionic multiple gestations. The reported incidence of fetus papyraceus is 1:12,000 live births and 1:184 twin births [1].

In the past, fetus papyraceus could only be diagnosed at the time of labor with vaginal palpation of fetal parts or with delivery of the fetus papyraceus which could also cause dystocia. Now, serial sonographic examinations can show intrauterine death and subsequent disappearance of one of twins.

Blunt trauma to the abdomen in the second trimester of pregnancy can result in intrauterine fetal death with subsequent fetus papyraceus of one twin [2]; this could be one of the contributory factors as seen in our case. The death of the fetus usually occurs early in the second trimester and retention of the fetus for a minimum of 10 weeks results in a flattened, mummified fetus. A co-twin dying earlier may be absorbed completely, whilst later fetal death usually results in macerated, but not compressed fetuses [3].

The distinction between monochorionic and dichorionic twins is important for both maternal and fetal prognosis; the prognosis for a surviving dichorionic twin is relatively good, with immaturity the main hazard [4]. By contrast the surviving monochorionic twin has a poor prognosis with a high frequency of neurological damage and cerebral palsy. Ante partum stillbirth, intrauterine growth retardation of the larger twin and maternal hypertension has also been reported [5]. Hysterotomy and selective delivery of an intrauterine dead fetus can be performed in order to prevent intrauterine death or brain damage of the surviving fetus in monochorionic twin pregnancy while a more conservative approach has been reported in dichorionic pregnancies in which pregnancy is actively continued with tocolytics, anti-infective prophylaxis; and monitoring of coagulation factors [6].

The death of one fetus may be associated with malformations of the surviving one. An unusual case of exomphalos with sirenomelia, imperforated anus and other multiple malformations in the surviving cotwin has also been reported in a twin pregnancy with papyraceus fetus [7].

Therefore, the appearance of a fetus papyraceus frequently indicates the presence of a hostile uterine environment.