Abnormal cortical plate (polymicrogyria), heterotopias and brain damage in monozygous twins

We report 5 cases of abnormal cortical plate (polymicrogyria or microgyric-like pattern) and heterotopias associated with hypoxic-ischemic brain injuries in monochorionic diamniotic twin fetuses of respectively 22, 26, 28, 31, 32 weeks gestation. These fetuses belonged to a series of 5 pairs of patients (10 cases) presenting with the characteristic features of the twin-to-twin transfusion syndrome. Three of them (2 donors and 1 recipient) were macerated and the brains were not available for study. Two (most likely recipient twins) survived. In the remaining 5 fetuses (3 donors and 2 recipients) with neuropathological study there were cortical plate abnormalities. In 2 cases, the cortex was dysmorphic and consisted of focal nodular distribution or vertical stripes of neurons. True polymicrogyria was focal in 2 cases and involved almost the entire surface of the hemispheres in another one. Heterotopias of immature cells were found in 4 cases, either in the white matter or in the cortex or in both sites. There was a focal laminar necrosis only in 2 cases. The morphological pattern of the anomalies depends on the time of occurrence of the insult and on its severity. These abnormalities, although similar to those already described in singleton fetuses, illustrate the variety of cortical dysmorphia which may be associated with fetal hypoxic-ischemic injuries and emphasize the particular vulnerability of the brain in monozygotic twins, whether it belongs to the donor or the recipient.

An acardiac infant: the extreme form of the twin-twin transfusion syndrome

A description of the pathologic and clinical findings in a twin with twin-to-twin transfusion syndrome is given. One of them died immediately after birth, with the autopsy revealing the histologic absence of the myocardium. The surviving infant presented with short term heart failure and with persistent left ventricular hypertrophy over 6 months. The circulatory changes in the twin-to-twin transfusion syndrome can result in complete myocardial involution in one and an unexpectedly long compensatory left ventricular hypertrophy in the other infant. Caution is advised in order to avoid misdiagnosing hypertrophic cardiomyopathy. In such a case a longer follow-up period is recommended.

In utero development of pulmonary artery calcification in monochorionic twins: a report of three cases and discussion of the possible etiology

Pulmonary artery (PA) calcification is unusual in children, reportedly occurring only in conjunction with severe underlying valvular disease. Three newborns were found by chest X-ray study to have thin calcified rings of the PA. Two were pump twins in twin reversed arterial perfusion (TRAP) sequences, each with an acardiac cotwin, and the third was the recipient in a twin transfusion syndrome (TTS). Both twin pairs with TRAP sequence were premature, each pump twin presenting with cardiac decompensation. One remained well at 5 months of age, the other died at 5 1/2 months of age. The third, the premature recipient of twins with TTS, died at 24 h of age, and the donor cotwin died at 2 h of age. The two hearts were structurally normal at autopsy. Subtle intimal wrinkling was seen above the pulmonary valve leaflets, and the media was yellow and granular on cut section. Hyperplasia of the intima and media with disruption and calcification of the elastic fibers of the media was seen microscopically. These three cases of PA calcification occurring in utero were not related to structural valvular abnormalities but were presumably due to increased cardiac output in utero as each occurred in the volume-overloaded twin of the twin pair. Comparison of the weight differences between these three twin pairs with PA calcification suggests a relationship between the presence of PA calcification and the severity of the cardiac volume overload. In utero cardiac damage may contribute to the high morbidity and mortality rate seen in infants with TRAP sequence and TTS.

The role of velamentous cord insertion in the etiology of twin-twin transfusion syndrome

OBJECTIVE

To evaluate the prevalence of velamentous cord insertion in twin-twin transfusion using the hypothesis that such insertions may contribute to the etiology of the condition.

METHODS

All cases of placentas referred for pathologic evaluation at the University of California at San Francisco from 1984-1992 were reviewed for the citation of diamniotic-monochorionic placentation, including the presence of velamentous cord insertions. Maternal and infant records were studied for findings consistent with twin-twin transfusion syndrome.

RESULTS

Thirty-eight cases of monochorionic-diamniotic twins were identified, 11 of which showed twin-twin transfusion syndrome. The prevalence of velamentous cord insertion in the transfusion syndrome subset was 63.6%, compared with 18.5% in those without (significant difference at P < .01). Twin-twin transfusion syndrome pregnancies with velamentous insertions were delivered at a significantly earlier gestational age; they also had fewer surviving infants and were more likely to have been treated prenatally than transfusion syndrome pregnancies without velamentous insertion, although these latter two findings were not significantly different.

CONCLUSIONS

Velamentous cord insertions are more common in twin-twin transfusion syndrome pregnancies and may contribute to the development of profound disparity in fluid volume because the membranously inserted cord can be easily compressed, reducing blood flow to one twin. Large-volume amniocentesis may reduce this compressive force on the cord insertion, thus explaining the success of this mode of intervention.

Effect of ACE inhibition on the fetal kidney: decreased renal blood flow

The kidneys of nine fetuses whose mothers were chronically hypertensive were examined microscopically. Three of these mothers used antihypertensive agents throughout pregnancy including one who used an angiotensin-converting enzyme (ACE) inhibitor. The tubular defects found in these kidneys were compared to the kidneys of 20 normal controls, 13 fetuses with various multiple malformation syndromes and six cases of the twin to twin transfusion syndrome. Evidence from these cases as well as the literature suggest that the primary mechanism by which ACE inhibitors affect development of the fetal kidney is through decreased renal blood flow.

[Pathology of the placenta. XI. Feto-fetal transfusion syndrome]

An account is given in this part of the series of placental alterations in the foeto-foetal transfusion syndrome of monochorial twin pregnancies. Arteriovenous or less often arterio-arterial anastomoses between the two parts of the placenta were found to be conditions for such foeto-foetal transfusion. Blood is discharged on the foetal side from one twin to the other, with one of the twins being adversely affected in growth and general development (donor), which may be as bad as acardia in case of very early onset of transfusion. The other twin (recipient) will undergo better development but will as well be impaired by cardiac hypertrophy and other organic lesions due to excessive inflow of blood. The placenta of the donor--quite often meeting intra-uterine death--usually is smaller than that of the recipient. It is severely anaemic and, additionally, may be of inadequate maturity. The placenta of the recipient may exhibit strongly pronounced hyperaemia, up to A and B angiomatosis. The author describes two of his own cases, with reference being made to morphological findings.

Foot necrosis in a surviving fetus associated with twin-twin transfusion syndrome and monochorionic placenta

Twin gestations with diamniotic monochorionic placentas have increased perinatal morbidity. We report a case in which, following the death of one member of a set of twins, absent end-diastolic flow was noted. At delivery, we noted thrombosis of placental vessels and vascular connections between the placental vessels of the larger and the smaller twins. The surviving twin was also noted to have necrosis of the right foot, consistent with a thromboembolic phenomenon.

Acute twin-twin transfusion: a possible mechanism for brain-damaged survivors after intrauterine death of a monochorionic twin

Intrauterine death of one twin in monochorionic pregnancies is associated with increased mortality and morbidity for the survivor. This has been attributed to the consequences of intrauterine disseminated intravascular coagulation (DIC) initiated by the dead twin. We describe a case in which the fetal cerebral and renal lesions typically found in survivors occurred without any derangement in coagulation. Instead, acute twin-twin transfusion was suggested by the presence of severe anemia in the surviving fetus at delivery. We suggest that the lesions frequently found in the survivors are often due to acute hemodynamic and ischemic changes resulting from acute twin-twin transfusion at the time of intrauterine death, rather than to late-onset DIC. This hypothesis has an important implication for future management: Intervention must occur before intrauterine death if neurologic sequelae in the survivor are to be prevented.

Fetoscopic neodymium:YAG laser occlusion of placental vessels in severe twin-twin transfusion syndrome

Most pregnancies with severe twin-twin transfusion syndrome before 27 weeks' gestation result in perinatal death. Previous attempts at therapy have been generally unsatisfactory and rarely successful. We have developed a technique for intrauterine ablation of the vascular communications between the fetoplacental circulations with a fetoscopically directed neodymium:YAG laser. The operation was performed on three women at risk for pregnancy loss from acute hydramnios at 18.5, 22, and 22.5 weeks' gestation. The first two procedures were uneventful, but the third was complicated by a placental vessel perforation. The first two patients delivered at 27 and 34 weeks after premature rupture of membranes and spontaneous labor, whereas the third woman developed severe preeclampsia at 29 weeks which necessitated delivery. Four of the six infants survived. Clinical and ultrasonographic evidence, as well as pathologic examination of the placentas, suggested that stabilization or resolution of the syndrome was due to photocoagulation of the vascular communications. This initial experience suggests that fetoscopic laser occlusion of placental vessels is feasible and superior to previous therapies because it treats the underlying pathophysiology directly.

Pathology of intragestational intervention in twin-to-twin transfusion syndrome

Selective intervention in multiple pregnancy is being used to enhance the chances of survival of at least one conceptus when the risks for the combined conceptuses and mother are considered too great. These procedures have been applied to induced polyembryonic conceptions (selective continuance) and discordant dichorionic twins (selective birth). We report attempts at selective intervention in three monochorionic twin gestations affected by twin-to-twin transfusion syndrome. In all three cases, both fetuses seemed doomed and the mother was in significant distress. The selected survivor in the first case is doing well; both twins were stillborn in the second case; in the third case, the selected survivor died as a neonate but the other twin survived and is doing well. We suggest possible explanations for the clinical outcome of each case based on detailed pathologic examination of the delivered placentas and autopsy examination of the nonsurviving twins. The shared chorionic circulation is the source of both the clinical disorder and the potential complications of any attempt to alleviate the disorder. This situation is unique to monochorionic twins, and we discuss the implications of this for intrauterine therapy of twin-to-twin transfusion syndrome.

Perinatal outcome in very preterm births with twin-twin transfusion syndrome

We retrospectively studied 48 pairs of twin gestations delivered between 24 and 28 weeks' gestation from 1975 to 1986 at Vanderbilt University Medical Center. The incidence of fetofetal transfusion syndrome was 20%, more than double the incidence previously reported in large series of twin deliveries that encompassed a wider gestational age range. The overall mortality was 55%, and mortality for the fetofetal transfusion group was 70%, whereas a subset of the fetofetal transfusion group, those without weight discordancy, had a mortality rate of 75%. Our findings suggest that traditional reliance on ultrasonographic criteria for diagnosis of fetofetal transfusion will not detect 40% of such cases. The poor outcome data suggest a need for innovative approaches to diagnosis and treatment.

Placental characteristics in twin transfusion syndrome

The authors describe the histological features of the placenta in a typical case of twin-to-twin transfusion, with particular attention focused on the stereologic aspects. Villi from the anemic placental portion were slightly edematous, with small and inconspicuous vessels. The stereologic characteristics of this portion were nearer values of normal placentas. The plethoric region appears as a postmature organ, with a very thin trophoblast layer and numerous vasculo-syncytial membranes. The most dramatic alterations of this region were mainly related to the foetal capillary. According to the stereologic results, the consecutive circulatory alterations would facilitate the maternal-fetal exchanges in the plethoric placental territory, thus justifying the greater development of this twin.

Vascular anastomoses in fused, dichorionic twin placentas resulting in twin transfusion syndrome

We have provided pathologic documentation of vascular anastomoses across fused, dichorionic placentas. These placental anastomoses resulted in the twin transfusion syndrome.

Clinical pathology conference: acute twin-to-twin in utero transfusion

This clinical pathology conference discusses a case of monochoriontic twins with chronic twin-to-twin transfusion based on unequal venous return and a large arterial communication. Polyhydramnios resulted in preterm labor, fetal distress, and a reversed acute twin-to-twin transfusion through the arterial shunt.

Nonimmunologic hydrops fetalis: a clinicopathological study of 50 autopsy cases

Fifty cases of nonimmunologic hydrops fetalis found in Japanese infants are reported. Nonimmunologic hydrops fetalis is associated with various pathological conditions, twin transfusion syndrome including acardiac monsters, fetal heart diseases, congenital cystic adenomatoid malformation, pulmonary sequestration, pulmonary lymphangiectasia, intrauterine infections such as cytomegalovirus infection and neonatal hepatitis, congenital neuroblastoma, Kasabach-Merritt syndrome, cystic hygroma, and chromosomal aberrations. The mechanism of hydrops fetalis found in these conditions is discussed from various viewpoints. Despite a careful examination, no causative conditions were found in 14 cases. The placenta showed a proliferation of Hofbauer cells that were strongly positive for immunoreactive alpha 1-antichymotrypsin and there were other common findings such as edema of terminal villi and fibrin thrombi.

Cystic brain lesion in utero

Two autopsy cases of cystic brain lesion in utero are reported. One of them was a donor infant of twin transfusion syndrome. The baby died immediately after birth and showed multicystic encephalomalacia in the distribution of the anterior cerebral artery. The second baby was a stillborn infant with thanatophoric dwarfism with associated chronic periventricular leukomalacia (PVL). It was suggested that the multicystic encephalomalacia and chronic PVL found in the first and second cases were caused by persistent circulatory disturbances in utero.

Placental injection studies in twin gestation

Vascular communication between placental vessels can occur when there is a fused placental mass in twin gestation. The presence of anastomotic channels can lead to the twin-twin transfusion syndrome in the fetuses. A study was conducted on 278 twin pairs to determine the incidence of vascular communication in fused twin placentas and the frequency of twin-twin transfusion syndrome. Anastomotic communication was found almost universally in monochorionic placentation and very rarely with dichorionic placentas. Twin-twin transfusion syndrome occurred uncommonly despite the high frequency of occurrence of cross-placental vascular communication. Misdiagnosis of intrauterine growth retardation in one twin can be avoided by determination of chorionicity by inspection of the placentas of twin gestation.

Antenatal diagnosis of twin transfusion syndrome by ultrasound

The evaluation of 2 cases of twin transfusion syndrome by conventional and real-time B-scan ultrasound is described. The importance of differentiating this syndrome from the isolated growth failure of 1 fetus in a twin pregnancy with a normally developing second fetus is emphasized. Assessment of placentation, fetal size and activity, as well as amount of fluid by diagnostic ultrasound is an important aid in the management of multiple gestation.

Physiomorphology of twin transfusion syndrome. A study of 86 twin gestations

The placentas of 86 pairs of twins were examined and correlated with the clinical characteristics of the neonate. The incidence of twin pregnancy in this group was 1 : 108 deliveries. Fetal prematurity and associated complications in twin pregnancy were the cause of increased perinatal and neonatal mortality.

Pathomorphologic changes of the cardiovascular system in twins

The author reports on primary diseases and on secondary reactions of adaptation in fetal hearts of twins. Cases of fibroelastosis endocardica, cases of hypertrophy of the heart, and the circulatory reactions following feto-fetal transfusion in twins, are discussed.

Using histochemical methods, several enzymes of the myocardium in deceased twins have been investigated.