Fetal upper mediastinum - normal and abnormal findings in obstetric ultrasound screening.

Fetal cardiac assessment is an integral part of the obstetric ultrasound. The inclusion of the outflow tracts and the three-vessel and tracheal view into the ultrasound screening enhances the detection rate for cardiovascular anomalies. Both, international and Polish guidelines recommend routine evaluation of the upper mediastinum. The aim of the study was to present the principles for assessing the structures of the upper mediastinum in normal conditions and to draw attention to the pathologies which may be visible in this plane.

Fetal mediastinal teratoma: Misinterpretation as congenital cystic lesions of the lung on prenatal ultrasound.

Congenital mediastinal teratoma can lead to development of hydrops fetalis and may be misinterpreted on ultrasound. In this case report, ultrasound revealed severe fetoplacental hydrops, moderate posthemorrhagic hydrocephalus, and multiple pulmonary cysts suggesting cystic adenomatoid malformation and displacement of the heart to the left side. Autopsy of the hydropic 24-weeks male fetus showed a large cystic-solid mediastinal mass that was consistent with nonmetastatic immature teratoma. It also demonstrated thymic, cardiac and pulmonary hypoplasia, and confirmed the germinal matrix-intraventricular hemorrhage. Accurate prenatal diagnosis of mediastinal teratoma may be achieved by a careful Doppler ultrasound assessment that also allows evaluating the fetal outcome.

Fetal Congenital Pulmonary Airway Malformation: The Role of an Objective Measurement of Cardiomediastinal Shift.

OBJECTIVE: To examine the relationship between cardiomediastinal shift angle (CMSA) and adverse perinatal outcomes and hydrops in cases of congenital pulmonary airway malformation (CPAM). STUDY DESIGN: This retrospective study evaluated CPAM cases referred to our institution from 2008 to 2015. The primary outcome was a composite score for adverse perinatal outcome. CMSA was measured for each case and evaluated for its association with the primary outcome. The prediction accuracy of CMSA for adverse perinatal outcome was assessed using receiver operator characteristic (ROC) curves. RESULTS: Eighteen (21.2%) of the 85 cases experienced an adverse perinatal outcome. Increases in CMSA were associated with adverse perinatal outcomes and hydrops in bivariate analyses. Adjusted analyses found each 10-degree increase in CMSA to be associated with increased odds of an adverse perinatal outcome (adjusted odds ratio [aOR] 2.2, 95% confidence interval [CI]: 1.4-3.3) and hydrops (aOR 3.0, 95% CI: 1.5-6.1). CMSA performed well and was comparable to CPAM volume ratio in predicting adverse perinatal outcomes (area under the curve 0.81 and 0.84, respectively). CONCLUSION: We describe a novel measurement of mediastinal shift in cases of CPAM and its relationship with adverse perinatal outcomes and hydrops. These findings may shape the evaluation and management of CPAMs, improve our understanding of their prognosis, and influence patient counseling.

Potential direct communication of the lung to the mediastinum: computed tomographic evaluation of pulmonary venous connections.

PURPOSE: We hypothesized that the remnant of the primitive pulmonary venous plexus in the embryo provides a pathway for direct communication from each lobe of the lung to the mediastinum. We assessed the presence and location of these connections by using 64-row multidetector computed tomography (CT). MATERIALS AND METHODS: This study was approved by the institutional ethics committee. First, we analyzed the multidetector row CT images of 120 normal lungs for the presence of septal structures between the pulmonary veins and the mediastinum and the extension of mediastinal fat into these septal structures. Second, we analyzed 62 patients with pneumothorax for the presence of cross-bridging structures in the pleural cavities. RESULTS: We frequently observed septal structures (36% to 77%) and the extension of mediastinal fat (8% to 56%) in the right apical segment, left apical posterior segment, both right and left anterior segments, right medial segment, and left inferior lingular segment. Cross-bridging structures were observed in 44% of right and 38% of left pneumothoraces and were noted in the right apical and posterior segments, left apical posterior segment, both anterior segments, right middle lobe, and left lingular segments. Septal and cross-bridging structures both showed a similar distribution pattern. CONCLUSIONS: Venous septal structures in normal lungs and cross-bridging structures in pneumothoraces visualized on CT images suggest the presence of direct pathways from each lobe of the lung to the mediastinum.

Prenatal diagnosis of posterior mediastinal lymphangioma by two- and three-dimensional ultrasonography.

Lymphangioma is a rare benign tumor characterized by proliferating lymph vessels and composed of large cyst spaces with endothelium-lined channels of varying dimensions. The incidence of lymphangioma is approximately one in 6000 pregnancies. Less than 1% of lymphangiomas are purely mediastinal. The great majority of cases are of cystic lymphangioma, but very rarely there is a mixed lesion consisting of multiple cysts of dilated capillary and lymph vessels. We report a case of posterior mediastinal lymphangioma diagnosed at 28 weeks' gestation, in which three-dimensional ultrasonography was helpful in determining the precise location of the tumor. A Cesarean section was performed at 39 weeks and the tumor was resected on the 5(th) day postdelivery; histological examination revealed a mixed cystic lymphangioma.

Cystic lesions of the mediastinum.

Cysts of the mediastinum comprise a relatively diverse group of lesions that include neoplastic and nonneoplastic constituents, the latter of which are largely congenital in nature. Therefore, a grasp of their clinicopathologic characteristics is bolstered by knowledge of which tumors in the chest may undergo cystic change, as well as the embryologic development of the thoracic organs. That information, as well as radiological and pathologic features of these lesions, is discussed in this review.

Mediastinal fetus in fetu. Case report and embryological discussion.

Fetus in fetu is an extremely rare condition defined by the presence of both axial skeleton and organoid formations in the parasitic mass. Besides some authors assuming that fetus in fetu and highly-differentiated teratomas are part of the same pathogenic spectrum, it has been emphasized that these criteria indicate a rather different embryogenetic mechanism. We herein report the first case to our knowledge developed in the ventral mediastinum that was thought to be a tumor before birth. The literature is reviewed and we propose a new explanation for the development of this rare anomaly, based on a defective implantation.

Congenital anomalies of the tracheobronchial tree, lung, and mediastinum: embryology, radiology, and pathology.

Congenital anomalies of the chest are an important cause of morbidity in infants, children, and even adults. The evaluation of affected patients frequently requires multiple imaging modalities to diagnose the anomaly and plan surgical correction. The authors analyze and illustrate practical aspects of certain common and uncommon congenital anomalies affecting the tracheobronchial tree, lung, and mediastinum, with emphasis on radiologic manifestations. Other thoracic anomalies such as rib anomalies and vascular rings are discussed when they are associated with anomalies of the tracheobronchial tree. The usefulness of the various imaging modalities in the diagnosis and treatment of these conditions is also evaluated. Specific topics addressed include tracheal conditions such as tracheal stenosis, tracheomalacia, tracheal bronchus, tracheal atresia, and bronchogenic cyst; anomalies of the lung such as lung underdevelopment (agenesis and hypoplasia), scimitar syndrome, congenital cystic adenomatoid malformation, congenital lobar emphysema, and pulmonary sequestration; esophageal anomalies such as esophageal atresia, tracheoesophageal fistula, and esophageal duplications; and vascular rings. The embryologic and pathologic basis of the radiologic findings are discussed in appropriate cases. Differential diagnoses, as well as pitfalls and diagnostic difficulties, are included.

The three vessels and trachea view (3VT) in fetal cardiac scanning.

OBJECTIVE: Comprehensive evaluation of the fetal heart has become a major part of targeted organ scanning to rule out fetal malformations. Evaluation of the mediastinal major vessels seems to be the most difficult and time-consuming part of fetal heart examination. Our aim was to define and evaluate the three vessels and trachea (3VT) view, a novel and simple method to examine the great vessels in the mediastinum, and its applicability in the clinical practice of fetal echocardiography, while establishing nomograms for cardiac vessel measurements obtained in this view. METHODS: The three vessels and trachea view was examined in 379 low-risk gravidae between 14+0 and 23+6 weeks' gestation. Six parameters in this plane were measured to establish nomograms. In another group of 984 mixed high- and low-risk patients we compared the time required to identify the aortic arch using the 3VT view as compared to the long-axis view. RESULTS: The 3VT view was readily and satisfactorily demonstrated in all but two of the 1363 cases examined. In 17 cases (out of a total of 982) more than 10 min were required to identify the aortic arch using the 3VT view and in 71 patients when employing the long-axis view (P < 0.001). CONCLUSION: The clinical applicability of the 3VT view to evaluate the anatomy of the major vessels in the mediastinum is demonstrated. Although a wide variation in the six parameters of the 3VT view used here precludes their use in diagnosing great vessel anomalies, some of the ratios between them have promising potential in the evaluation of great vessel malformations. Further, the 3VT view seems to be more efficient in identifying the aortic arch than does the long-axis view.

Thymopoiesis requires Pax9 function in thymic epithelial cells.

The epithelial thymic anlage develops from the third pharyngeal pouch. Pax9 is expressed in the entire pharyngeal endoderm, and its function is required for normal development of organs derived from pharyngeal pouches. Here, we show that in Pax9 null mice, the thymic anlage develops as an ectopic polyp-like structure in the larynx. It expresses Whn/Foxn1, a marker of thymic epithelium, but fails to perform the normal caudo-ventral movement to the upper mediastinum. The thymic rudiment contains mesenchymal cells, blood vessels and is colonized by T cell progenitors. However, from embryonic day 14.5 onwards, the size of the Pax9 mutant thymus is severely reduced. Whereas expression of TCRbeta chain genes is readily detectable in the mutant thymus, no expression of the TCRgamma chain was detectable. Our results identify a new genetically defined control point of thymopoiesis.

Embryology and surgical anatomy of the mediastinum with clinical implications.

This article discusses general mediastinal embryology, and provides anatomy and algorithms for the investigation of mediastinal masses. The superior, anterior, middle, and posterior mediastina also are detailed.

Three-vessel view of the fetal upper mediastinum: an easy means of detecting abnormalities of the ventricular outflow tracts and great arteries during obstetric screening.

The three-vessel view is a transverse view of the fetal upper mediastinum is as simple to obtain as the four-chamber view. It demonstrates the main pulmonary artery, ascending aorta and superior vena cava in cross- or oblique sections. The purposes of this study were to describe the normal anatomy of the three-vessel view and to analyze what anatomical changes would occur in this view when there are lesions of the ventricular outflow tracts and/or great arteries. Sonograms of 29 fetuses with lesions involving the ventricular outflow tracts and/or great arteries were reviewed. Three-vessel views were evaluated in terms of vessel size, number, arrangement and alignment. Twenty-eight of 29 fetuses showed an abnormal three-vessel view that included abnormal vessel size (n = 12), abnormal alignment (n = 8), abnormal arrangement (n = 7) and abnormal vessel number (n = 3). The vessel size was abnormal in obstructive lesions of the right (n = 4) or the left (n = 8) side of the heart. An abnormal alignment was seen in tetralogy of Fallot (n = 6) and double-outlet right ventricle (n = 2) that showed anterior displacement of the aorta. An abnormal arrangement was seen in complete (n = 4) and corrected (n = 1) transposition, double-outlet right ventricle (n = 1) and pulmonary atresia with ventricular septal defect (n = 1). Only two vessels were seen in truncus arteriosus (n = 1). Four vessels were seen in persistent left superior vena cava (n = 2). A fetus with pulmonary atresia and intact ventricular septum showed a normal three-vessel view. In conclusion, most of the lesions involving the ventricular outflow tracts and/or great arteries showed an abnormal three-vessel view.

[Cervical thymic cysts. A clinical case report]. / Le cisti timiche cervicali. Presentazione di un caso clinico.

The presence of thymic residues in a laterocervical site is very rare, as is cystic degeneration. The paper reports the case of a six-year-old boy who presented a swelling in a left laterocervical site; preoperative tests (especially echography and fine needle aspiration) identified the cystic nature of the swelling which was then confirmed intraoperatively; histological test diagnosed a thymic cyst. The paper analyses the embryological, anatomopathological and clinical aspects of these formations and underlines the difficulty of making a differential diagnosis from other neck pathologies, especially branchial cysts. In conclusion, preoperative tests can only determine the cystic component but not the thymic origin of these formations which can only be confirmed by final histological tests.

[Histogenesis of the immune system of the "nude" mouse. Postnatal development of the thymus: a light microscopical study (author's transl)]. / Histogenese des Immunsystems der "nude" Maus. II. Postnatale entwicklung des Thymus: eine lichtmikroskopische Studie

UNLABELLED: Mice homozygous for the mutation "nude" display a dysgenetic thymus (Pantelouris, 1968). The anterior mediastinum of these animals contains a rudimentary epithelial organ (pantelouris and Hair, 1970), which has been assumed to represent not a maldeveloped thymus, but rather a remnant of the parathyroid gland or of the ultimobranchial body (Wortis et al., 1971). We have investigated the development of the thymus in homo- and heterozygous nude by both light and electron microscopy. This paper describes the light microscopical findings in embryos and fetuses from the 11th up to the 18th day post conceptionem (pc). MATERIALS AND METHODS: Homo- and heterozygous nude (nu/nu + nu/+) mice with the genetic background BALB/c were kept under specific pathogen-free (spf) conditions. Virgin nu/+ females were mated with nu/nu males. In addition, homozygous females were mated with homozygous males in order to investigate 11-day-old homozygous embryos. The embryos and fetuses were fixed in Bouin's solution and embedded in paraffin wax. Serial frontal sections (5mu) were stained with hematoxylin and eosin. RESULTS AND DISCUSSION: Up to the 12th day pc, the thymus anlage of the n/nu embryo is indistinguishable from that of the nu/+ animal. The paired anlage develops from the epithelium of the ventral and dorsal diverticles of the 3rd pharyngeal pouch, and from the ectodermal vesicula cervicalis. In the nu/+ embryo, the thymic epithelium begins to proliferate between the 12th day and 13th day pc. In the central part of the anlage, the epithelial cells dissociate and begin to form a reticulum. At the same time, blood vessels from the surrounding mesenchyme invade the anlage. From the 14th day onwards, lymphoblasts are recognizable..