Comparison of postoperative urinary complications in laparoscopic-assisted anorectoplasty versus posterior sagittal anorectoplasty for anorectal malformation with rectourethral fistula.

BACKGROUND: Long-term urinary outcomes after anorectal malformation (ARM) repair are affected by surgical approach and sacral anomalies. This study aimed to compare laparoscopic-assisted anorectoplasty (LAARP) and posterior sagittal anorectoplasty (PSARP) in terms of urinary complications. METHODS: Between 2001 and 2022, 45 patients were treated with LAARP or PSARP. The rectourethral fistula and inflow angle between the fistula and rectum was confirmed by preoperative colonography. The incidence of urinary complications and treatment were compared between the two groups. RESULTS: Four patients (14%) had remnant fistula and five patients (17%) had neurogenic bladder dysfunction in LAARP group, while three patients (18%) had urethral injury in PSARP group. All patients with remnant fistula were asymptomatic and followed without treatment. The incidence of remnant fistula improved between earlier decade and later decade. In all cases with urethral injury, suture repair was performed and no postoperative leakage was noted. All five patients with neurogenic bladder dysfunction had spine abnormalities that required clean intermittent catheterization (CIC) and two were free from CIC finally. CONCLUSIONS: It is important to check inflow angle preoperatively to prevent remnant fistula. For PSARP, meticulous dissection is required when separating fistula from urethra because they create common wall. The most contributing factor to neurogenic bladder is sacral anomalies. Preoperative evaluation and postoperative urinary drainage are important.

The clinical impact of macrophage polarity after Kasai portoenterostomy in biliary atresia.

Introduction: Biliary atresia (BA) is a cholestatic hepatopathy caused by fibrosing destruction of intrahepatic and extrahepatic bile ducts, and its etiology has not been clearly revealed. In BA, liver fibrosis progression is often observed even after Kasai portoenterostomy (KPE), and more than half of cases require liver transplantation in their lifetime in Japan. Macrophages play an important role in liver fibrosis progression and are classically divided into proinflammatory (M1) and fibrotic macrophages (M2), whose phenotypic transformation is called "macrophage polarity." The polarity has been reported to reflect the tissue microenvironment. In this study, we examined the relationship between macrophage polarity and the post-KPE clinical course. Materials and methods: Thirty BA patients who underwent KPE in our institution from 2000 to 2020 were recruited. Multiple immunostainings for CD68, CD163, CK19, and α-SMA were carried out on liver biopsy specimens obtained at KPE. ROC curves were calculated based on each clinical event, and the correlation with the clinical data was analyzed. Results and discussion: The M2 ratio, defined as the proportion of M2 macrophages (CD163-positive cells), was correlated inversely with the occurrence of postoperative cholangitis (AUC: 0.7602). The patients were classified into M2 high (n = 19) and non-high (n = 11) groups based on an M2 ratio value obtained from the Youden index ( = 0.918). As a result, pathological evaluations (Metavir score, αSMA area fraction, and CK19 area fraction) were not significantly different between these groups. In mild liver fibrosis cases (Metavir score = 0-2), the M2 non-high group had a significantly lower native liver survival rate than the high group (p = 0.02). Moreover, 4 out of 8 cases in the M2 non-high group underwent early liver transplantation within 2 years after KPE. Conclusions: Non-M2 macrophages, including M1 macrophages, may be correlated with postoperative cholangitis, and the M2 non-high group in mild liver fibrosis cases had a significantly lower native liver survival rate than the high group, requiring early liver transplantation in this study. Preventing advanced liver fibrosis is a key factor in improving native liver survival for BA patients, and liver macrophages may play important roles in liver homeostasis and the promotion of inflammation and fibrosis.

Current treatment strategies for postoperative intrahepatic bile duct stones in congenital biliary dilatation: a single center retrospective study.

BACKGROUND: Intrahepatic bile duct (IHBD) stones are one of the most common late complications of Roux-en-Y hepaticojejunostomy for congenital biliary dilatation (CBD). We report the current treatment strategies for IHBD stones and their outcomes in our institute. METHODS: Between 1983 and 2021, 117 patients with CBD were surgically treated in our institute. Our treatment strategies included oral ursodeoxycholic acid (UDCA), double-balloon endoscopic retrograde cholangiography (DB-ERC), percutaneous cholangio-drainage (PTCD), and open surgery. A retrospective study was conducted using medical charts. RESULTS: Postoperative IHBD stones were identified in 12 of 117 patients with CBD (10.2%). Five patients received UDCA, and small stones were successfully resolved in two cases. DB-ERC was performed eight times in five patients, but the endoscope could not reach the porta hepatis due to a long jejunal loop in two of five patients. One patient presented with severe acute pancreatitis induced by prolonged DB-ERC. PTCD was performed in three patients, two of whom finally underwent open surgery due to unsuccessful lithotomy. Open surgery was eventually performed in three patients. Lithotomy was performed in one patient; lithotomy with strictureplasty was performed in another patient. The other patient was diagnosed with intrahepatic cholelithiasis with adenocarcinoma. He underwent left lobectomy and died of carcinomatous peritonitis. CONCLUSIONS: Oral UDCA may be effective for small stones. Although DB-ERC should be considered as a first-line interventional therapy for lithotomy, it may not be feasible due to a long jejunal loop, and pancreatitis may occur. Long-term follow-up and early detection and treatment for IHBD stones may yield a good prognosis.

IL13 and periostin in active fibrogenic areas of the extrahepatic bile ducts in biliary atresia patients.

BACKGROUND: The leading pathology of biliary atresia (BA) is inflammatory and fibrous obstruction of extrahepatic bile duct, but the pathogenesis remains unclear. IL13 is a cytokine associated with allergies and inflammatory fibrosis, and periostin induces fibrogenesis by stimulation with IL13. We analyzed the involvement of IL13 and periostin in inflammatory fibrosis in the extrahepatic bile duct of BA patients. MATERIALS AND METHODS: Surgically resected tissues from the hepatic hilar area of BA patients were immunostained with CD45, α-SMA, IL13 and periostin and statistically analyzed. Fibroblasts from the resected tissue were cultured with recombinant IL13, and periostin production was analyzed by quantitative polymerase chain reaction and Western blotting. RESULTS: IL13 was stained in 93% of large and micro bile ducts, and 92.1% matched with the CD45 location (p = 0.006) around the large bile ducts. Periostin staining correlated with the localization of IL13 and αSMA (p < 0.001) around the large bile ducts. Periostin mRNA and protein were upregulated by IL13 stimulation in cultured fibroblasts. CONCLUSION: IL13 was associated with induced periostin expression by fibroblasts, playing a vital role in the pathogenesis of fibrogenesis around the extrahepatic bile duct in BA.

Predictive factors for fundoplication following esophageal atresia repair.

BACKGROUND: One of the most frequent complications after repair of esophageal atresia (EA) is gastroesophageal reflux disease (GERD). Although GERD-associated EA is known to often require anti-reflux surgery, the predicting factors remain unclear. We retrospectively analyzed EA in our institution. METHODS: Of 65 children with EA treated in our hospital from 1995 to 2018, 45 with Gross C type EA, followed for over 1 year, were enrolled in this study. The patients were divided into fundoplication and non-fundoplication groups and compared in terms of their clinical features. RESULTS: The fundoplication and non-fundoplication groups included 13 and 32 cases, respectively. On univariate analysis, gestational age, body weight, prenatal diagnosis, polyhydramnios, re-do surgery, and gap length of the esophagus differed significantly between the groups (P < 0.05). CONCLUSION: Early delivery, low body weight, and a long gap length are, are considered to be risk factors for fundoplication. However, the present study further showed that prenatal diagnosis and polyhydramnios were also significant contributing factors. The presence of a prenatal diagnosis and polyhydramnios may induce preterm delivery, therefore, cases of polyhydramnios due to suspected EA should be managed to prevent early delivery. Better understanding of the postnatal course after surgery is required, especially for prenatal diagnosis cases.

Maldevelopment of intrapulmonary bronchial cartilage in congenital diaphragmatic hernia.

BACKGROUND: Pulmonary hypoplasia is an important cause of morbidity and mortality in infants with congenital diaphragmatic hernia (CDH). This study aimed to verify our hypothesis that the abnormal development of bronchial cartilage as well as alveolar immaturity, might play a central role in hypoplasia of the lung in human CDH. METHOD: We retrospectively analyzed autopsied lungs from 10 CDH cases and compared with nine age-matched controls to assess the bronchial cartilage and alveolar maturity using morphological techniques. RESULT: Ki-67 and thyroid transcription factor-1 (TTF-1) expression in the alveoli significantly increased in bilateral lungs with CDH. The shortest distance from the bronchial cartilage to the pleura was significantly shorter in ipsilateral (left) lungs with CDH, showing a positive correlation with the radial alveolar count (RAC). Regarding the small bronchial cartilages less than 20 000 µm2 , the average cartilage area significantly decreased in left lungs with CDH, and tended to decrease in right lungs with CDH. In addition, cartilage around the bronchi less than 200 µm in diameter tended to be smaller in left lungs with CDH. In contrast, regarding the cartilage around the bronchi 200 to 400 µm in diameter, the ratio of the total cartilage area relative to the bronchial diameter tended to be higher in left lungs with CDH, although there was a large variation. CONCLUSIONS: These opposite directional cartilage abnormalities around the distal and more proximal bronchi support our hypothesis that abnormal development of bronchial cartilage might play an important role in the hypoplastic lung in CDH.

The roles played by the MYCN, Trk, and ALK genes in neuroblastoma and neural development.

Neuroblastoma is one of the most frequent, yet distinctive and challenging childhood tumors. The uniqueness of this tumor depends on its biological markers, which classify neuroblastomas into favorable and unfavorable, with 5-year survival rates ranging from almost 100-30%. In this review, we focus on some biological factors that play major roles in neuroblastoma: MYCN, Trk, and ALK. The MYCN and Trk family genes have been studied for decades and are known to be crucial for the tumorigenesis and progression of neuroblastoma. ALK gene mutations have been recognized recently to be responsible for familial neuroblastomas. Each factor plays an important role in normal neural development, regulating cell proliferation or differentiation by activating several signaling pathways, and interacting with each other. These factors have been studied not only as prognostic factors, but also as targets of neuroblastoma therapy, and some clinical trials are ongoing. We review the basic aspects of MYCN, Trk, and ALK in both neural development and in neuroblastoma.

Thoracoscopic resection for mediastinal thymolipoma in a child.

Thymolipoma is a rare disease among benign tumors. We herein report the case of a child who underwent thoracoscopic resection of a large thymolipoma. A 3-year-old boy was diagnosed with an anterior mediastinal solid tumor. Thoracic imaging revealed a fat density mass that was 8.0 × 5.0 × 3.5 cm in size. Given the MRI findings of the tumor, we suspected that the lesion was a teratoma. We decided to perform thoracoscopic exploration and, if possible, resection of the solid tumor sequentially. We successfully resected the tumor thoracoscopically. A histological examination revealed thymolipoma. For large mediastinal tumors in the intrathoracic space in children, the thoracoscopic approach is recommended when the tumor is preoperatively considered to be benign and resectable.

Laparoscopic intraperitoneal onlay mesh for pediatric incisional hernia-a case report.

BACKGROUND: The incidence of incisional hernia in pediatric patients is low in comparison with that reported in adults. In the pediatric population, primary closure has generally been favored. However, synthetic or biomedical mesh offers advantages in the repair of larger defects when primary closure is difficult. The use of laparoscopic intraperitoneal onlay mesh (IPOM) in the adult population has been well documented. In the pediatric population, a few laparoscopic approaches with direct suturing have been proposed; however, there are no reports of laparoscopic repair with the use of IPOM. CASE PRESENTATION: The patient was a 1-year-old girl with epigastric incisional hernia after an operation to correct a complete arteriovenous septal defect. The fascial defect (size 30 × 35 mm) was large; thus, direct suturing was considered to be associated with a high risk of thoracic deformation and recurrence. Laparoscopic IPOM was performed. The fascial defect was detected precisely through the laparoscopy, and non-absorbable mesh was placed through a 12-mm trocar. Minimal incisions were required for the trocars, and extensive dissection of the abdominal wall structure was not needed. This procedure allowed for the integrity and functional status of the abdominal wall to be maintained. CONCLUSION: Laparoscopic IPOM is a minimally invasive and cosmetically acceptable method that can be applied to the treatment of large incisional hernias in children.

Tumor-homing effect of human mesenchymal stem cells in a TH-MYCN mouse model of neuroblastoma.

BACKGROUND: Human mesenchymal stem cells (hMSCs) are multipotent stem-like cells that are reported to have tumor-suppression effects and migration ability toward damaged tissues or tumors. The aim of this study was to analyze the tumor-homing ability of hMSCs and antitumor potency in a transgenic TH-MYCN mouse model of neuroblastoma (NB). METHODS: hMSCs (3×106) labeled with DiR, a lipophilic near-infrared dye, were intraperitoneally (i.p.) or intravenously (i.v.) administered to the TH-MYCN mice. hMSC in vivo kinetics were assayed using the IVIS® imaging system for 24h after injection. Immunohistochemistry using human CD90 antibody was also performed to confirm the location of hMSCs in various organs and tumors. Furthermore, the survival curve of TH-MYCN mice treated with hMSCs was compared to a control group administered PBS. RESULTS: i.p. hMSCs were recognized in the tumors of TH-MYCN mice by IVIS. hMSCs were also located inside the tumor tissue. Conversely, most of the i.v. hMSCs were captured by the lungs, and migration into the tumors was not noted. There was no significant difference in the survival between the hMSC and control groups. CONCLUSION: The present study suggested that hMSCs may be potential tumor-specific therapeutic delivery vehicles in NB according to their homing potential to tumors.

Surgical intervention and perioperative risk factors of retroperitoneal teratomas in children: a single institution experience.

PURPOSE: Retroperitoneal teratomas (RTs) are rare among germ cell tumors and predominantly occur in infants. RTs are often difficult to manage by perioperative management. In this study, we retrospectively reviewed our series of RTs. METHODS: Seventy patients with germ cell tumors were treated from 1989 to 2015 in our institution. Fourteen patients had RTs (3 boys and 11 girls). The median age at diagnosis was 5.5 months (range 0-64), and three were antenatally diagnosed. RESULTS: All except one patient underwent total tumor excision. They exhibited dense adhesions with major vessels, and ligation of the splenic and gastroduodenal arteries was required in two patients. Injuries of PV and renal artery occurred in two patients. IVC injury in a neonate with a giant mass caused circulatory failure and brain death occurred postoperatively. Other major complications included injury of the diaphragm and bile duct. An infant whose tumor compressed the superior mesenteric artery developed enteritis while waiting for surgery and non-occlusive mesenteric ischemia, resulting in massive intestinal necrosis. The perioperative complication rate was 50 %. CONCLUSION: Surgery for RTs remains challenging, and a preoperative evaluation of the vascular anatomy is crucial due to the high complication rate. Moreover, pre- and intraoperative fluid management is important to avoid any unexpected fatalities.

Successful laparoscopic extirpation of a large omental lipoblastoma in a child.

Omental lipoblastoma is extremely rare among benign tumors. We herein report the case of a child who underwent laparoscopic extirpation of a large omental lipoblastoma. A 4-year-old girl was diagnosed with an intra-abdominal solid tumor. Abdominal imaging revealed a fat density mass that was well encapsulated and measured 18 × 15 × 7.5 cm in size. Considering the MRI findings and movability of the tumor, we strongly suspected that the lesion was an omental lipoblastoma. We initially decided to perform laparoscopic exploration and, if possible, extirpation of the solid tumor sequentially. A total of five trocars were used, and the tumor was found to originate from the omentum. We successfully performed complete resection of the tumor laparoscopically. A histological examination revealed lipoblastoma. For large abdominal tumors in children, the laparoscopic approach is recommended as the first procedure when the tumor is preoperatively considered to be benign and resectable.

Surgical intervention strategies for pediatric congenital cystic lesions of the lungs: A 20-year single-institution experience.

BACKGROUND: The aim of this study was to assess surgical intervention strategies for congenital cystic lesions of the lungs (CCL), focusing on the safety of lung resection. MATERIALS AND METHODS: The clinical features of 27 children (CCAM, n=16; bronchial atresia, n=4; bronchogenic cyst, n=3; pulmonary sequestration, n=3; lobar emphysema, n=1) who were treated at our institution between 1995 and 2014 were analyzed. RESULTS: Of the 27 patients, 14 were asymptomatic, and 13 were symptomatic. The youngest symptomatic patient presented with pneumonia at 9months of age. The mean age at surgery was 4months in the asymptomatic group and 4.1years in the symptomatic group. The mean operating time was 167minutes in the asymptomatic group and 275minutes in the symptomatic group (P<0.001). The mean amount of intraoperative bleeding was 15g in the asymptomatic group and 83.4g in the symptomatic group (P<0.05). All of the prenatally diagnosed patients underwent surgery within six months of birth. Three patients had remnant cystic lesions, all of which involved cystic lesions located over the lobulation anomalies of the lung. CONCLUSIONS: To minimize surgical invasiveness, surgery for CCL should be performed during the asymptomatic period or within six months after birth.

Double and synchronous trichobezoars causing small-bowel obstruction and detected by multidetector computed tomography: report of two cases.

A trichobezoar is a rare mass formed by the ingestion and accumulation of hair within the gastrointestinal tract, especially the stomach. Cases of an isolated gastric trichobezoar with extension into the duodenum or the jejunum have been reported; however, synchronous gastric and intestinal trichobezoars causing a small-bowel obstruction is very unusual. We report our experience of two such cases to demonstrate the efficiency of preoperative multidetector computed tomography in locating the double bezoars and assisting us in surgical decision making. Open surgery is inevitable for symptomatic bezoars, because the masses are too hard and large to break up with endoscopic devices.

Prenatal administration of neuropeptide bombesin promotes lung development in a rat model of nitrofen-induced congenital diaphragmatic hernia.

BACKGROUND/PURPOSE: Fetal medical treatment to improve lung hypoplasia in congenital diaphragmatic hernia (CDH) has yet to be established. The neuropeptide bombesin (BBS) might play an important role in lung development. The present study aims to determine whether prenatally administered BBS could be useful to promote fetal lung development in a rat model of nitrofen-induced CDH. METHODS: Pregnant rats were administered with nitrofen (100mg) on gestation day 9.5 (E9.5). BBS (50mg/kg/day) was then daily infused intraperitoneally from E14, and fetal lungs were harvested on E21. The expression of PCNA was assessed by both immunohistochemical staining and RT-PCR to determine the amount of cell proliferation. Lung maturity was assessed as the expression of TTF-1, a marker of alveolar epithelial cell type II. RESULTS: The lung-body-weight ratio was significantly increased in CDH/BBS(+) compared with CDH/BBS(-) (p<0.05). The number of cells stained positive for PCNA and TTF-1 was significantly decreased in CDH/BBS(+) compared with CDH/BBS(-) (p<0.01). The TTF-1 mRNA expression levels were significantly decreased in CDH/BBS(+) compared with CDH/BBS(-) (p<0.05). CONCLUSIONS: Prenatally administered BBS promotes lung development in a rat model of nitrofen-induced CDH. Neuropeptide BBS could help to rescue lung hypoplasia in fetal CDH.

Clinical analysis of liver fibrosis in choledochal cyst.

PURPOSE: Although most patients with choledochal cyst (CC) have a favorable prognosis with prompt treatment, some of them are complicated with liver fibrosis, resulting in prolonged liver dysfunction even after definitive surgery. The aim of this study was to distinguish the high-risk group of liver fibrosis in patients with CC. METHODS: Fifteen patients who underwent liver biopsy during surgery for CC from 1981 to 2012 were enrolled in this study. Liver histology with H&E staining was graded according to Ohkuma's classification, and the correlation with the clinical characteristics was retrospectively assessed. RESULTS: Their median age at biopsy was 13.4 months (range 1-42 months), and there were 7 in Ia, 2 in Ic, and 6 in IVa of the Todani classification. There were no significant differences in serum liver function test among those cyst types. The histological grades of liver fibrosis were as follows: grade 0 (no fibrosis) in 7 patients, grade 1 (mild) in 2, grade 2 (moderate) in 3, grade 3 (severe) in 2, grade 4 (cirrhosis) in 1. All 3 patients with grade 3 and 4 had CC with IVa and were under 18-month old. A 3-month-old girl with cirrhosis presented with severe jaundice resulting in living-donor liver transplantation despite bile drainage. A 16-month-old girl with grade 3 suffered from prolonged liver dysfunction and intractable ascites after surgery. CONCLUSIONS: The progression of liver fibrosis is likely to be correlated with IVa, and the postoperative course might be unsatisfactory in advanced cases. The prompt surgical intervention is recommended especially for neonatal and infantile cases with type IVa cyst because irreversible liver cirrhosis could occur as early as in the infantile period.

Impact of our new protocol on the outcome of the neonates with congenital diaphragmatic hernia.

BACKGROUND/PURPOSE: Congenital diaphragmatic hernia (CDH) remains a defiant challenge for pediatric surgeons. Since 2003, we developed a new protocol aiming for the better outcome. In this study, the usefulness of our new protocol was evaluated. MATERIALS AND METHODS: Forty-six neonates with CDH at the age of less than 24 h were divided into two groups based on the difference of era and treatment protocols. In Group 1, 15 patients were treated between 1997 and 2002 and 31 patients were treated between 2003 and 2011 in Group 2. In the latter group, a new protocol was introduced focusing on the prevention of lung edema as well as lung injury by steroid administration and on the stabilization of cardiopulmonary function using continuous D-mannitol infusion. The survival rate and the postoperative intubation period (POIP) were compared between the two groups. RESULTS: The overall survival rate was significantly increased from 53 % (8/15) to 81 % (25/31) (p < 0.05). In isolated CDH, the survival rate was increased from 58 to 93 %. The average POIP was remarkably shortened from 39.0 to 4.4 days (p < 0.01). CONCLUSION: Our new protocol remarkably improved the survival rate and shortened the period of mechanical ventilation in neonates with CDH.

Infrared spectrophotometry of intraluminal meconium calculi in a neonate with imperforate anus and rectourethral fistula.

BACKGROUND/PURPOSE: Intraluminal meconium calculi are a rare cause of neonatal abdominal calcifications in patients with anorectal malformations. To investigate their pathogenesis, we performed infrared spectroscopic analysis of meconium-calcified lesions. METHODS: Meconium calculi were collected from the colostomy in a newborn patient with imperforate anus and rectourethral fistula. The potassium bromide method was employed to obtain the infrared absorption spectrum of the meconium calculi. RESULTS: The wavelength pattern of the meconium calculi exhibited 4 specific peaks at 1570, 1390, 1105, and 1005 cm(-1) between 22% and 45% transmittance values. The unique absorption spectrum exclusively indicated ammonium hydrogen urate (C(5)N(5)O(3)H(7)), having the combined constituents of ammonium and uric acid. CONCLUSIONS: These results suggest that the intraluminal meconium calculi were originally derived from meconium and fetal urine. The stasis of meconium passage and fetal urine mixing through the rectourethral fistula in a low-pH condition was deduced to be the main cause of this rare stone formation.

Developmental study of tethered spinal cord in murine embryos with anorectal malformations.

BACKGROUND/PURPOSE: Tethered spinal cord is frequently associated with anorectal malformations (ARMs). However, it remains unknown how the tethered spinal cord develops and relates to the severity of ARM. We studied the development of the spinal cord in ARM mouse embryos induced by all-trans retinoic acid (ATRA). METHODS: Pregnant ICR-Slc mice were administered 100 mg/kg of ATRA on the ninth embryonic day (E9.0). Embryonic specimens were obtained from the uteri between E11.0 and E18.5. Midsagittal histologic sections focusing on the spinal cord and pelvis were prepared for immuonhistochemistry specific for neurofilament and Protein Gene Product 9.5 molecules. RESULTS: More than 98% of ATRA-treated embryos demonstrated ARM with rectourethral or rectocloacal fistula. Normal embryos exhibited progressive ascent of the spinal cord from E14.5. However, in ARM embryos, the distal spinal cord ended with meningomyelocelelike or atypical hamartomatous lesions at E11.5 to E13.5, which later caused stretch force that damaged the spinal cord, resulting in tethered cord between E16.0 and E16.5. CONCLUSIONS: In ATRA-induced ARM mouse embryos, tethered spinal cord was mostly established, accompanied by caudal neural maldevelopment, during early fetal development. This experimental model may be useful for researching detailed neuropathologic conditions in ARM children accompanied with tethered spinal cord.

Iodine 123 metaiodobenzylguanidine radio-guided navigation surgery for recurrent medullary thyroid carcinoma in a girl with multiple endocrine neoplasia type 2B.

Multiple endocrine neoplasia type 2B (MEN 2B) is an inherited cancerous syndrome characterized by medullary thyroid carcinoma (MTC), adrenal pheochromocytoma, marfanoid habitus, and enteric ganglioneuromatosis. In this syndrome, a high frequency of persistent elevation of the serum calcitonin level, a sensitive marker for MTC, after total thyroidectomy has been reported, and the prognosis of such patients depends upon complete resection of recurrent MTC by repeated surgery. The authors performed iodine 123 metaiodobenzylguanidine ((123)I-MIBG) radio-guided navigation surgery for recurrent MTC in a 14-year-old girl with MEN 2B. She had undergone 4 neck operations, including total thyroidectomy at the age of 7 years. An intravenous injection of 100 MBq (123)I-MIBG was followed by the fifth surgery. At surgery, the cervical and upper mediastinal areas were filled with adhesional scar tissue, in which a gamma-scintillation probe conducted hot spots of isotope uptake by cancerous cells. Histopathology of resected specimens showed scattered nests of MTC cells corresponding to gamma-scintillation counts. Intraoperative (123)I-MIBG scanning is of substantial benefit for children with MEN 2B undergoing surgery for recurrent MTC.