Massive true thymic hyperplasia with osseous metaplasia.

True thymic hyperplasia is defined as an increase in both the size and weight of the gland, while maintaining a normal microscopic architecture. Massive true thymic hyperplasia is a rare type of hyperplasia that compresses adjacent structures and causes various symptoms. Limited reports address the imaging findings of massive true thymic hyperplasia. Herein, we report a case of massive true thymic hyperplasia in a 3-year-old girl with no remarkable medical history. Contrast-enhanced CT revealed an anterior mediastinal mass with a bilobed configuration containing punctate and linear calcifications in curvilinear septa, which corresponded to lamellar bone deposits in the interlobular septa. To our knowledge, this is the first report of massive true thymic hyperplasia with osseous metaplasia. We also discuss the imaging features and etiology of massive true thymic hyperplasia with osseous metaplasia.

Genetic relatedness of a new Japanese isolates of Alexandrium ostenfeldii bloom population with global isolates.

In recent years, blooms of toxic Alexandrium ostenfeldii strains have been reported from around the world. In 2013, the species formed a red tide in a shallow lagoon in western Japan, which was the first report of the species in the area. To investigate the genetic relatedness of Japanese A. ostenfeldii and global isolates, the full-length SSU, ITS and LSU sequences were determined, and phylogenetic analyses were conducted for isolates from western and northern Japan and from the Baltic Sea. Genotyping and microsatellite sequence comparison were performed to estimate the divergence and connectivity between the populations from western Japan and the Baltic Sea. In all phylogenetic analyses, the isolates from western Japan grouped together with global isolates from shallow and low saline areas, such as the Baltic Sea, estuaries on the east coast of U.S.A. and from the Bohai Sea, China. In contrast, the isolates from northern Japan formed a well-supported separate group in the ITS and LSU phylogenies, indicating differentiation between the Japanese populations. This was further supported by the notable differentiation between the sequences of western and northern Japanese isolates, whereas the lowest differentiation was found between the western Japanese and Chinese isolates. Microsatellite genotyping revealed low genetic diversity in the western Japanese population, possibly explained by a recent introduction to the lagoon from where it was detected. The red tide recorded in the shallow lagoon followed notable changes in the salinity of the waterbody and phytoplankton composition, potentially facilitating the bloom of A. ostenfeldii.

Toxin Profiles of Okadaic Acid Analogues and Other Lipophilic Toxins in Dinophysis from Japanese Coastal Waters.

The identification and quantification of okadaic acid (OA)/dinophysistoxin (DTX) analogues and pectenotoxins (PTXs) in Dinophysis samples collected from coastal locations around Japan were evaluated by liquid chromatography mass spectrometry. The species identified and analyzed included Dinophysis fortii, D. acuminata, D. mitra (Phalacroma mitra), D. norvegica, D. infundibulus, D. tripos, D. caudata, D. rotundata (Phalacroma rotundatum), and D. rudgei. The dominant toxin found in D. acuminata was PTX2 although some samples contained DTX1 as a minor toxin. D. acuminata specimens isolated from the southwestern regions (Takada and Hiroshima) showed characteristic toxin profiles, with only OA detected in samples collected from Takada. In contrast, both OA and DTX1, in addition to a larger proportion of PTX2, were detected in D. acuminata from Hiroshima. D. fortii showed a toxin profile dominated by PTX2 although this species had higher levels of DTX1 than D. acuminata. OA was detected as a minor toxin in some D. fortii samples collected from Yakumo, Noheji, and Hakata. PTX2 was also the dominant toxin found among other Dinophysis species analyzed, such as D. norvegica, D. tripos, and D. caudata, although some pooled picked cells of these species contained trace levels of OA or DTX1. The results obtained in this study re-confirm that cellular toxin content and profiles are different even among strains of the same species.

Pitfalls in the management of congenital tracheal stenosis: is conservative management feasible?

PURPOSE: Congenital tracheal stenosis (CTS) is rare and challenging. Complete tracheal rings cause a wide spectrum of airway-obstructing lesions and varying degrees of respiratory distress. Although surgical reconstruction is the primary option for symptomatic CTS, sometimes an appropriate management strategy may be difficult due to other anomalies. We aimed to identify pitfalls in the management of CTS. METHODS: We retrospectively reviewed the records of patients with CTS during the last 10 years in our institution. RESULTS: Sixteen pediatric patients were diagnosed with CTS. Of the 16 patients, 12 (75.0%) had cardiovascular anomalies including seven left pulmonary artery sling. Six patients with dyspnoea caused by CTS and three patients with difficult intubations due to CTS underwent tracheoplasty. Four patients underwent only cardiovascular surgery without tracheoplasty. Three asymptomatic patients were followed up without undergoing any surgical procedure. We repeatedly discussed management of four patients with especially complex pathophysiology at multidisciplinary meetings. Right ventricular outflow tract obstruction, tracheobronchial malacia, increased pulmonary blood flow, and pulmonary aspiration due to gastroesophageal reflux presumably accounted for their severe respiratory distress, and we forewent their tracheal reconstruction. CONCLUSION: The management of CTS should be individualized, and conservative management is a feasible option in selected cases.

A new paradigm of scarless abdominal surgery in children: transumbilical minimal incision surgery.

PURPOSE: This study aimed to evaluate the use of a transumbilical incision for infants and children, as well as neonates, with various intraabdominal conditions. METHODS: A retrospective study of transumbilical incision surgery was performed between June 2007 and June 2013. Patients were divided into two groups: group 1 of neonates and group 2 of infants and children. All operations were performed via an upper circumumbilical incision. RESULTS: Thirty-six patients (22 males, 14 females) were treated via a transumbilical incision, with 20 patients in group 1 and 16 patients in group 2. A transverse incision extension was needed for 1 case in group 1 (intestinal atresia complicated by meconium peritonitis) and 4 cases in group 2 (two with ileus owing to adhesive bands, 1 with malrotation, 1 with ectopic pancreatic tissue in the duodenum). In cases with a dilated intestinal wall or intraabdominal adhesions, an optional extension of the transverse incision might be required. Only 1 case with ileus in group 2 developed a wound infection that was treated by drainage. The postoperative cosmetic results were acceptable in all cases. CONCLUSION: The transumbilical incision yielded a sufficiently large surgical field, and the surgical condition was easily and directly viewed. In all 36 cases, an adequate operation was safely performed. This approach is a safe and effective method for various intraabdominal disorders in not only neonates but also infants and children, and leads to an imperceptible incision.

Surgical reconstruction and endoscopic pancreatic stent for traumatic pancreatic duct disruption.

Nonoperative management is acceptable treatment for minor pancreatic injuries. However, management of major pancreatic duct injury in children remains controversial. We present our experience in treating isolated pancreatic duct injury. We describe the cases of three male patients treated for complete pancreatic duct disruption in the past 5 years at our institution. We performed pancreatic duct repair to avoid distal pancreatectomy and to maintain normal pancreatic function. All patients underwent enhanced computed tomography and endoscopic retrograde cholangiopancreatography in the early period. The injuries were classified as grade III according to the American Association for the Surgery of Trauma classification. In two cases, we performed end-to-end anastomosis of the pancreatic duct during the delayed period. In the third case, we placed a stent across the disruption to the distal pancreatic duct. The patients' postoperative courses were uneventful, and the average hospitalization was 25.6 days after the procedure. At a median follow-up of 36 months (range 14-54 months), all patients remain asymptomatic, with normal pancreatic function, but with persistent distal pancreatic duct dilatation. We suggest that distal pancreatectomy should not be routinely performed in patients with isolated pancreatic duct injury.

Balloon tracheoplasty as initial treatment for neonates with symptomatic congenital tracheal stenosis.

Neonates with congenital tracheal stenosis (CTS) sometimes develop respiratory distress and may be difficult to intubate. We used balloon tracheoplasty with a rigid bronchoscope for emergency airway management in neonates with symptomatic CTS. Herein, we describe the balloon tracheoplasty procedure and the early outcomes following its use as the initial treatment of neonatal symptomatic CTS. We performed a retrospective analysis of five neonates with CTS who were initially treated with balloon tracheoplasty at our institution from January 2010 to December 2013. Five patients with a mean birthweight of 2,117 g were treated during the study period. Of these, four developed respiratory distress after birth, and all patients had difficult intubations. In all five patients, definitive diagnosis of CTS was made by rigid bronchoscopy and 3-dimensional reconstruction scan. A total of nine balloon dilatations were performed in five patients. Following balloon tracheoplasty, two patients were extubated, one was extubated after resection and end-to-end anastomosis following initial balloon dilatation, and one remained hospitalized with tracheostomy for tracheomalacia. The remaining patient died from tracheal bleeding associated with congenital heart disease. Although our sample size was small, balloon tracheoplasty is a potentially effective initial treatment for selected cases with neonatal symptomatic CTS.

Molecular and morphological discrimination between an invasive ascidian, Ascidiella aspersa, and its congener A. scabra (Urochordata: Ascidiacea).

The solitary ascidian Ascidiella aspersa (Müller, 1776) has sometimes been regarded as conspecific with A. scabra (Müller, 1776), although previous detailed morphological comparisons have indicated that the two are distinguishable by internal structures. Resolution of this taxonomic issue is important because A. aspersa has been known as a notoriously invasive ascidian, doing much damage to aquaculture e.g. in Hokkaido, Japan. We collected many specimens from European waters (including the Swedish coast, near the type localities of these two species) and Hokkaido, Japan (as an alien population) and made molecular phylogenetic analyses using the mitochondrial cytochrome c oxidase subunit I (COI) gene, and found that in terms of COI sequences all the analyzed specimens were clustered into two distinct groups, one of which is morphologically referable to A. aspersa and the other to A. scabra. Thus, these two species should be regarded as distinct from each other.

New operative strategy for refractory microcystic lymphangioma.

The optimal management of microcystic lymphatic malformations (LMs) in children has not been established. We describe how we used the Ligasure™ Vessel Sealing System (LVSS) to achieve partial resection of refractory microcystic LMs in a 1-year-old boy. The child was admitted in respiratory distress caused by infection and swelling of cervical LMs. The LMs had been diagnosed prenatally, but had not decreased in size despite three treatments with OK-432 sclerotherapy. We performed direct dissection of the microcystic LMs using the LVSS with minimal intraoperative blood loss or lymphatic leakage. The LMs were resected as completely as possible without damage to the jugular vein or major nerves. His postoperative course was uneventful. Histological examination revealed complete sealing of the lymphovascular channels with obliterated lumens. Resection using the LVSS is effective and easy to perform for partial resection of microcystic LMs. We recommend the combination of initial OK-432 injection therapy and subsequent partial resection using the LVSS for refractory microcystic LMs.

Management of blunt pancreatic trauma in children.

Blunt trauma to the abdomen accounts for the majority of abdominal injuries in children. Pancreatic injury is the fourth most common solid organ injury, following injuries to the spleen, liver and kidneys. The most common complications are the formation of pancreatic fistulae, pancreatitis and the development of pancreatic pseudocysts, which usually present several weeks after injury. The nonoperative management of minor pancreatic injury is well accepted; however, the treatment of more serious pancreatic injuries with capsular, ductal or parenchymal disruption in pediatric patients remains controversial. Based on the data presented in this literature review, although children with pancreatic injuries (without ductal disruption) do not appear to suffer increased morbidity following conservative management, patients with ductal disruption may benefit from operative intervention.

The efficacy of double-balloon enteroscopy for intrahepatic bile duct stones after Roux-en-Y hepaticojejunostomy for choledochal cysts.

INTRODUCTION: Intrahepatic bile duct (IHBD) stones are one of the most complicated morbidities that occur after Roux-en-Y hepaticojejunostomy (RYH); however, the optimal therapeutic approach is controversial. METHODS: Double-balloon enteroscopy (DBE) has been widely and frequently performed even in pediatric patients. We herein report the successful management of IHBD stones by biliary lithotripsy using DBE after RYH for a choledochal cyst (CC). DBE has made it possible to perform endoscopic therapeutic intervention, including balloon dilatation of an anastomotic stricture and removal of IHBD stones, without any major complications. CONCLUSION: DBE is a less invasive and safe treatment method for IHBD stones in pediatric patients, which is capable of reaching the bilioenteric anastomosis after RYH for CC.

Management of laryngotracheal stenosis in infants and children: the role of re-do surgery in cases of severe subglottic stenosis.

Although many advances have improved the treatment of congenital and acquired laryngotracheal stenosis in children over the past two decades, the therapeutic decision-making process remains challenging for pediatric surgeons and otolaryngologists. Severe subglottic stenosis is a complex laryngeal injury that necessitates multiple airway procedures, and the approach depends on the exact nature of the cicatricial lesion and its effect on the vocal cord mobility. Therefore, it is imperative that the pediatric surgeons and otolaryngologists dealing with this situation should be well trained in endoscopy and laser treatment, in addition to open surgical intervention. Open re-do surgery remains the best choice in cases of severe congenital stenosis, glottic immobility, or after two to three endoscopic procedures have been performed without any significant improvement.

Long-term outcomes of congenital tracheal stenosis treated by metallic airway stenting.

AIM: Congenital tracheal stenosis is an obstructive airway lesion that often presents as a life-threatening emergency. We had introduced the balloon dilatation and placement of the expandable metallic airway stent as a therapeutic option, and this study aimed to clarify the long-term outcomes in pediatric patients. METHODS: A retrospective review of five infants in whom balloon expandable metallic airway stents (10-40 mm long and 6-8mm in diameter) were inserted in 1997 to 2000 was conducted. RESULTS: There was an immediate improvement of respiratory obstruction in all five infants (aged 7 days to 12 months) with four weaned from ventilation. One child died after 9 months of palliative treatment. In all inflammation and granulation tissue developed over the stents, but this could be managed by scraping or balloon compression. Metallic stents have been in place a mean of 12 years (range 6 months to 13 years) after insertion without other complications. Four children are alive and well with their stents in place. Recently, an attempt to remove the stent was done in two patients who showed dyspnea on exertion. They underwent tracheoplasty following successful complete removal of metallic stent using cardiopulmonary bypass. CONCLUSION: Use of expandable metallic airway stents following balloon dilatation can be left for long periods to relieve tracheal obstruction. Development of granulation tissue is a major treatable complication. Removal of the stent was safely completed by open surgical intervention using a cardiopulmonary bypass. The airway stent may provide an important therapeutic option in selected cases with congenital tracheal stenosis.

A novel diagnostic and treatment strategy for small intestinal lesions in children: hybrid treatment using transumbilical minimal incision surgery combined with double-balloon enteroscopy.

INTRODUCTION: Double-balloon enteroscopy (DBE) is a useful and feasible modality for evaluating small intestinal lesions, even in children. METHODS: DBE makes it possible to perform biopsy, diagnosis, polypectomy and endoscopic therapies including hemostasis, tattooing and clipping of the small intestinal lesions. However, endoscopic procedures in the small intestines of children are more difficult than in adults, because the intestinal wall is thin and the lumen is narrow. A novel hybrid treatment was developed using DBE for small bowel lesions combined with transumbilical minimal incision surgery. CONCLUSION: This hybrid treatment is safe, effective, provides excellent cosmetic results and can be used as an alternative for traditional open laparotomy or endoscopic surgery.

Intrapericardial extralobar pulmonary sequestration detected as an intrathoracic cystic mass by using prenatal ultrasonography: case report and review of the literature.

Intrapericardial extralobar pulmonary sequestration is a very rare congenital lung anomaly. We report a case of this condition, detected as an intrathoracic cystic lesion by using prenatal ultrasonography. The neonate was born at 38 weeks of gestation with no progression of the lesion and no respiratory or cardiac symptoms. Ultrasonography and computed tomography (CT) revealed a 40 × 17 × 17-mm intrapericardial lesion, composed of cystic components and a solid component. Intrapericardial extrapulmonary sequestration was suspected largely because CT showed a vague aberrant artery. At the age of 3 months, elective surgery was performed, and the postoperative course was uneventful.

High-level congruence of Myrionecta rubra prey and Dinophysis species plastid identities as revealed by genetic analyses of isolates from Japanese coastal waters.

We analyzed cryptophyte nucleomorph 18S rRNA gene sequences retained in natural Myrionecta rubra cells and plastid 16S rRNA gene and psbA sequences retained in natural cells of several Dinophysis species collected from Japanese coastal waters. A total of 715 nucleomorph sequences obtained from 134 M. rubra cells and 564 plastid 16S rRNA gene and 355 psbA sequences from 71 Dinophysis cells were determined. Almost all sequences in M. rubra and Dinophysis spp. were identical to those of Teleaulax amphioxeia, suggesting that M. rubra in Japanese coastal waters preferentially ingest T. amphioxeia. The remaining sequences were closely related to those of Geminigera cryophila and Teleaulax acuta. Interestingly, 37 plastid 16S rRNA gene sequences, which were different from T. amphioxeia and amplified from Dinophysis acuminata and Dinophysis norvegica cells, were identical to the sequence of a D. acuminata cell found in the Greenland Sea, suggesting that a widely distributed and unknown cryptophyte species is also preyed upon by M. rubra and subsequently sequestered by Dinophysis. To confirm the reliability of molecular identification of the cryptophyte Teleaulax species detected from M. rubra and Dinophysis cells, the nucleomorph and plastid genes of Teleaulax species isolated from seawaters were also analyzed. Of 19 isolates, 16 and 3 clonal strains were identified as T. amphioxeia and T. acuta, respectively, and no sequence variation was confirmed within species. T. amphioxeia is probably the primary source of prey for M. rubra in Japanese coastal waters. An unknown cryptophyte may serve as an additional source, depending on localities and seasons.

Occurrence and detrimental effects of the bivalve-inhabiting hydroid Eutima japonica on juveniles of the Japanese scallop Mizuhopecten yessoensis in Funka Bay, Japan: relationship to juvenile massive mortality in 2003.

In November 2003, we first observed prevalent occurrence of a hydroid, Eutima japonica, on soft body tissues of age zero Japanese scallop (Mizuhopecten yessoensis) juveniles cultured in large areas of Funka Bay, Hokkaido. The occurrence coincided with massive death of juvenile scallops. A major objective was to clarify ecological relationships between the symbionts, and to infer the relationship between symbiosis and the massive mortality. To do this, we investigated distributions of association rates of hydroids with juvenile scallops at 15-34 sites over 3 years (2003-2005), with age one adult scallops at 24 sites in 2003, and with mussels at 13 sites in 2004. We studied seasonal changes in association rates with juvenile scallops, and numbers of polyps per juvenile scallop at three sites from November 2003 to June 2004. We also quantified the hydroid impacts on juvenile scallop shell length growth and triglyceride accumulation in the digestive gland. The association rate of E. japonica polyps with juvenile scallops was high in large areas of Funka Bay in 2003, and overlapped the distribution of mussels bearing polyps. Association rates with age one adult scallops were very low in November 2003, even at the sites where polyps were very common on juvenile scallops. Levels of hydroid occurrence in juvenile scallops varies by year. We found that hydroids presence in juvenile scallops declined drastically in 2004 and 2005. The association rates with juvenile scallops, and numbers of polyps per juvenile scallop declined during winter, until they disappeared completely in the following June. Since polyps were rare in adult scallops, we believe that infection of juvenile scallops was probably initiated from the planulae produced by medusae released from polyps growing on Mytilus spp., especially M. galloprovincialis. Subsequently, the inhabitation spread intraspecifically and interspecifically. In juvenile scallops, inhabitation of polyps reduced shell length growth by 43%, and triglyceride accumulation in digestive glands by 24-47%. Inhabitation of E. japonica on juvenile scallop is best regarded as parasitism, rather than inquilinism or commensalism. Occurrence of polyps was probably not a direct lethal factor for juvenile scallops, because there were some sites where association rates were high, but mortalities were low. Massive mortalities in 2003 may have resulted from simultaneous impacts of heavy polyp load and stresses caused by the way in which the animals were handled (transferred from cages for pre-intermediate culture to cages for intermediate culture), because the massive mortality occurred within a month of the transfer. The presence of polyps in juvenile scallops does not affect the quality of the product in Funka Bay, because market size scallops are hydroid-free.