1/14. Morphological and cytogenetic studies on conjoined twins.Two cases of monoamniotic conjoined male twins, born at term after normal pregnancies, are reported. The first case, a bicephalus, shows hypoplastic and malformed left-side organs, absence of the left umbilical artery, and two communicating hearts, the left one with three cameras. The second case, a pygothoracopagus, consists in a twin "parasite", with no head but with two upper and two lower limbs, slightly less developed than those of the formed twin. The left eye of the formed twin is double than the right one and contains two eye apples -- one well-formed and the other rudimentary. There is a rudiment of a second mouth on the left cheek. The umbilical cord contains five blood vessels |
one umbilical vein and four umbilical arteries. The cytogenetic study of the pygothoracopagus reveals aneuploidy, more pronounced in the "parasite" than in the formed twin. |
2/14. Monocephalus diprosopus, a rare form of conjoined twins, and associated congenital anomalies.Craniofacial duplication (diprosopus) is a rare form of conjoined twins. A case of monocephalus diprosopus with anencephaly, cervicothoracolumbar rachischisis, and duplication of the respiratory tract and upper gastrointestinal tract is reported. The cardiovascular system remained single but the heart showed transposition of the great vessels. We present this case due to its rarity, and compare our pathologic findings with those already reported.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
3/14. Abnormal umbilical vessels and systemic circulatory reversal in thoracopagus twins.A human thoracopagus of slightly unequal twins having a common umbilical cord with exomphalos is described with special reference to the cardiovascular system. The larger twin had single umbilical artery. The smaller twin had a large left umbilical artery which was in direct continuity with the aorta, a small right umbilical artery with sole connection to the right external and internal iliac arteries (right common iliac artery was absent), missing umbilical vein, a rudimentary nonfunctional heart with atresia of the truncus arteriosus, and a right-sided aortic arch. Exomphalos of both twins is accounted by the possible defective growth of umbilical mesoderm caused by abnormal umbilical vessels. Reversal of sustemic circulation in the upper part of the body of small twin is discussed. The importance of a careful study of umbilical veins is emphasized.- - - - - - - - - - ranking = 5keywords = vessel (Clic here for more details about this article) |
4/14. Prenatal sonographic delineation of the complex cardiac anatomy of thoraco-omphalopagus twins.We describe a case of thoraco-omphalopagus twins diagnosed at 18 weeks' gestation. Each twin had a separate set of anatomical structures except for a shared heart, upper liver and anterior chest wall. The heart was located at the center of the juncture, and consisted of three atria and two ventricles, each twin having a single ventricle and right atrium but a fused left atrium. A set of great arteries originated from each single ventricle and there was juxtaposition of the aortic and pulmonary valves. One twin had transposition of the great arteries, whereas in the other these were normal in configuration. There was only one umbilical cord which contained four vessels (two arteries and two veins). This case report demonstrates the possibility of using fetal echocardiography to delineate the cardiovascular complex of the conjoined heart.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
5/14. Unique anomalies in cephalothoracopagus janiceps conjoined twins with implications for multiple mechanisms in the abnormal embryogenesis.The anatomic features of female conjoined twins with the Janiceps type of cephalothoracopagus are described. Abnormalities included bilateral clefts of the alveolar arches, shared rudimentary mandible, high, arched clavicles, multiple rib deformities, single shared foregut and small intestine, absent large intestines, omphalocele, multicystic kidneys, hypoplastic lungs, interconnected aortas and neck vessels, single ovary with elongated uterus in each twin, displaced labia, abnormal segmentation of the vertebrae, spinal dysraphism, diastasis of the symphysis pubis, malrotated lower extremity, bilateral posterior dislocation of the hips, and club feet. There were two hearts with internal anomalies. Both spinal cords had a myelocele in the lumbar region. The abnormalities noted in previous reports of conjoined twins of this type are reviewed and compared. We propose that factors associated with conjoining, dysgenetic (developmental) defects, and deformations resulting from crowding in utero all may have been important in the abnormal development in this case.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
6/14. Laterality defects in conjoined twins: implications for normal asymmetry in human embryogenesis.We evaluated six pairs of conjoined twins: four pairs were dicephalus, and two were of the ischiopagus type. In three of the four dicephalus pairs, the right twin had an abnormality of laterality that included a right aortic arch, reversed great vessel orientation, bilateral right-sided isomerism of the lungs, asplenia, and situs inversus of the viscera. The left twin had normal great vessel orientation and situs solitus in each case. The finding that was unique in these three dicephalus twin pairs was their fused hearts, which were similar in orientation and configuration. The fourth dicephalus twin pair had one normally rotated heart, which was located in the midline and had normally placed chambers and great vessels. Each twin of this pair had normal visceral situs. In the two pairs of ischiopagus twins, each pair had two separate hearts, with normal cardiac structure and great vessel relationships. The viscera expressed normal laterality. documentation of a defect in laterality in the right twin in three conjoined twin pairs with fusion of the hearts, combined with the presence of normal laterality in three pairs without cardiac fusion, has implications regarding the mechanisms leading to laterality of the human embryo. We suggest that rotation of the heart initiates the embryo's process of lateralization and that the laterality defects of the viscera seen in the right twin are a result of their abnormal cardiac rotation.- - - - - - - - - - ranking = 4keywords = vessel (Clic here for more details about this article) |
7/14. Cardiovascular anomalies in conjoined thoracopagus twins.Necropsy findings in 3 cases of conjoined thoracopagus twins are presented. Conjoined hearts were seen lying in a common pericardial cavity. In 2 cases the common atrial complex was incompletely divided into the atrial cavities of the twins by ridges arising from the floor of the cavity. In 1 case the atrial division was better defined and the interatrial septal defect of septum secumdum type was seen. pulmonary veins opened normally into the atrial chamber only in 1 case, in the other 2 cases, these veins opened into the inferior vena cava and the liver respectively. Ventricular chambers were common in 2 cases with 3 rudimentary atrioventricular openings guarding the inlet and multiple VSD of muscular type. In 1 case one twin had 2 completely separated ventricular cavities and the other twin had partially separated ventricular cavities with a muscular VSD. Great vessels showed transposition in all the cases. In 1 case d-transposition of a rare variety was seen which was associated with a subaortic as well as subpulmonic conus. Persistent ductus arteriosus was a cmmon feature and valvular type of pulmonic stenosis was seen in 2 cases.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
8/14. Triventricular heart with three atrioventricular valves in a conjoined twin.An infant, who was conjoined to a partially formed twin, died from congenital cardiac disease which could not be diagnosed accurately by catheterization and cineangiography. Pathologic examination showed a triventricular heart with three atrioventricular valves. One great vessel system was present, and the aorta was transposed. The findings in this infant suggest that the incorporation of cardiac anlage from an incompletely or abortively formed fetus may explain the presence of supernumerary structures in complex congenital cardiac malformations.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
9/14. Assessment of the cardiovascular system in conjoined thoracopagus twins.The thoracoomphalopagus conjoined twins comprise 75% of all conjoined twins. In the assessment of the organ systems of the twins, the cardiovascular system is important since union of this system in the twins has occurred in 75% of the cases. Of the five cases reported here, two had separate hearts and vessels with a common pericardium only. Two twins were joined at the right atrial level. The fifth pair were connected at both atrial and ventricular levels. It has been suggested that the presence of two separate QRS complexes in the ECG indicates complete separation of the two hearts. Case 4 shows that even in the presence of atrial union, the existence of an atrioventricular block in one twin may produce a very slow heart rate, while the other twin may have a normal rate that will not influence the ventricular rate of the other. In our experience, angiocardiography has been the most useful diagnostic procedure.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
10/14. Early cardiac evaluation of thoracically conjoined twins.Thoracopagus conjoined twins were delivered at 31 weeks gestation by cesarean section. Although there was a single heart, the possibility of salvaging one twin only was contemplated. echocardiography revealed an A-V canal and suspected transposition of the great vessels. To determine the possibility of surgery, cardiac catheterization was performed to rule out other congenital cardiac malformations incompatible with life, and also to delineate the exact anatomy of the great vessels of the heart. Unfortunately, complex congenital abnormalities were found, thus excluding the possibility of surgery. Newly delivered conjoined twins should be regarded as potentially correctable and should be promptly investigated while they are yet in good clinical condition.- - - - - - - - - - ranking = 2keywords = vessel (Clic here for more details about this article) |
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