Geoffrey K. Blair

Rhabdomyosarcoma arising within congenital pulmonary cysts : report of three cases

Over the past 9 months, three cases of primary pulmonary rhabdomyosarcoma have been treated at British Columbia Childrens Hospital. Two patients (aged 24 and 37 months) presented with spontaneous pneumothoraces and had cystic changes in the affected lung on chest radiograph. The third patient (aged 42 months) was evaluated for chronic cough, fever, and failure to thrive. Chest x-ray showed a large mass in the left lower lobe as well as mediastinal adenopathy. All three of these lesions originated within congenital lung cysts, one a peripheral bronchogenic cyst and the others cystic adenomatoid malformations. This report suggests that there is a significant risk for the development of rhabdomyosarcoma within malformed pulmonary tissue.

Inflammatory pseudotumors in children

Inflammatory pseudotumors are so named because they mimic malignant tumors clinically and radiologically. Most often seen in the lungs of young adults, they consist of localized proliferations of mononuclear inflammatory cells and myofibroblasts. There are scattered reports of these tumors occurring in various sites in children. We report five cases of these rare lesions in children; four arising intraabdominally and one in the lung. In contrast to the usual presentation in adulthood, these children were all previously healthy. One child, with the tumor arising from the urinary bladder, was originally diagnosed as having a malignant sarcoma and underwent pelvic exenteration and chemotherapy for this subsequently-proven benign lesion. Local recurrence occurred in one case. Total excision is indicated and is usually possible without unacceptable morbidity. Our cases and a review of the literature point out the importance of pathologic differentiation of these lesions from malignancy with early appropriate surgery.

Age is the major determinant of recurrence in pediatric differentiated thyroid carcinoma

BACKGROUND A relationship between young age and increased risk of recurrence of pediatric differentiated thyroid carcinoma has been suggested; however, no attempts have been made to assess the prognostic factors or efficacy of treatment in very young children with this malignancy. The objectives of this study were to evaluate the association of age with outcome in pediatric differentiated thyroid carcinoma and to compare the clinical, pathologic, prognostic, and treatment variables between younger and older children with this disease. PROCEDURE A retrospective review of all patients presenting to the British Columbias Childrens Hospital or British Columbia Cancer Agency <17 years of age at diagnosis with differentiated thyroid carcinoma between January, 1955, and December, 1996, was completed. RESULTS Thirty-eight patients were identified, 12 of whom were </=10 years of age. The overall and relapse-free survivals at 20 years were 100% and 32.2%, respectively. Age at diagnosis was the only determinant of time to recurrence on univariate and multivariate regression analysis of prognostic factors (P = 0.022). The 20 year relapse-free survival for children < or =10 years of age was 10.1% vs. 48.3% for children >10 years. An association between young age and extrathyroidal tumor invasion was identified (P = 0.016); however, the latter factor did not independently predict outcome. There was a trend for suppressive doses of thyroid hormone to improve outcome, particularly with increasing age at diagnosis, but this was not statistically significant. CONCLUSIONS Age is the major determinant of recurrence in pediatric differentiated thyroid carcinoma. The results suggest different tumor biology in young children requiring novel approaches to therapy to decrease recurrence rates.

Pediatric thyroid fine-needle aspiration cytology: a meta-analysis

BACKGROUND There is conflicting evidence in the current literature regarding the use of fine-needle aspiration (FNA) biopsy in the diagnosis of a thyroid nodule in the pediatric population. There are numerous studies that look at the sensitivity and specificity of this test with varying results. A meta-analysis will provide further insight into this topic. PURPOSE Our objective was to investigate the diagnostic parameters of FNA biopsy in the diagnosis of a thyroid nodule in the pediatric population, specifically, to determine the sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of the test in differentiating malignant vs benign tumors. MATERIAL AND METHODS We performed a literature search of Medline, Embase, and evidence based medicine (EBM) reviews for English studies that looked at FNA biopsy in thyroid nodules in the pediatric population, in which diagnostic values were present or could be calculated and where FNA results were compared to an acceptable reference standard. Two reviewers independently selected all abstracts, and from these, studies to review. Two reviewers also independently checked diagnostic values in the studies or calculated them from data available. A meta-analysis was performed, and pooled diagnostic test values were calculated using a random-effects, bivariate meta-regression model. Studies were also assessed for quality using the quality assessment for diagnostic accuracy studies tool. RESULTS Twelve studies were included for review. The quality of the studies in general was good. The pooled estimate of sensitivity and specificity were 94% (95% confidence interval [CI], 86%-100%) and 81% (95% CI, 72%-91%), respectively. Assuming 20% of nodules are malignant, the accuracy, PPV, and NPV were 83.6%, 55.3%, and 98.2%, respectively. CONCLUSION This meta-analysis provides good evidence that FNA biopsy of thyroid nodules is a sensitive test in the pediatric population and may be a useful tool for excluding malignancy in young patients. Future prospective studies are needed to evaluate this further.

Tumor karyotype differentiates lipoblastoma from liposarcoma

Lipoblastoma is a rare benign pediatric soft tissue tumor that may be difficult to distinguish from a myxoid liposarcoma clinically or histologically. The authors present a case of a progressively growing, locally invasive soft tissue tumor in a child. Tissue culture for cytogenetic study showed a breakpoint in the long arm of chromosome 8. A review of the literature showed seven case reports of lipoblastoma karyotype, six of which had a similar breakpoint in chromosome 8. This distinguishes it from the histologically alike myxoid liposarcoma, the karyotype of which typically contains the clonal anomaly t(12;16)(q13:p11). The authors recommend that when performing a biopsy of a childhood adipose tumor with unusual features, such as progressive or invasive growth, that fresh tissue be submitted for cell culture. The tumor karyotype will, in most cases, aid in differentiating lipoblastoma from myxoid liposarcoma.

Proximity injury by the ultrasonically activated scalpel during dissection

The ultrasonically activated scalpel is a high-frequency oscillating instrument that is reported to have a decreased dispersion of energy to surrounding tissues during use. To determine if this effect is beneficial and safe to surrounding tissue, it was used on anesthetized adolescent swine to dissect the portal vein from the pancreas, the renal artery and vein from the renal hilum, the ureter from the retroperitoneum, the aorta from the inferior vena cava and the common bile duct from surrounding tissue. Three-second contact to intestine and nerve roots was also performed. Wedge biopsy specimens of liver and spleen were performed. Dissection technique used was as described by the company. Structures were dissected with electrocautery using similar techniques for comparison. Tissues were harvested and placed in formalin for histological analysis. Dissection with the ultrasonically activated scalpel was simple, achieved excellent hemostasis, and did not appear to damage adjacent tissue. Microscopic analysis showed adventicial and media injury to vascular structures. The ureter and common bile duct demonstrated marked injury with regions of transmural coagulation. Nerve and small bowel did not appear to have much injury from the 3-second contact with the instrument. This study indicated that although the ultrasonically activated scalpel can ease dissection with good hemostasis, care must be taken to avoid injury to adjacent structures. Although its lateral energy dispersion may be less than that of cautery, it can still cause transmural necrosis to major structures.

Does the transition zone reliably delineate aganglionic bowel in Hirschsprung's disease?

Background: Knowledge of the extent of aganglionic bowel is important for preoperative planning of trans-anal surgery in patients with Hirschsprung’s disease (HD). Objective: To evaluate the accuracy of the transition zone, as identified by contrast enema study, for identifying the extent of aganglionic bowel. Materials and methods: A total of 32 patients with preoperative contrast enema studies and pathologic identification of aganglionic extent were reviewed. Two pediatric radiologists independently reviewed the contrast enema studies. The radiographic transition zone was compared to the pathological extent of aganglionic bowel. Results: Radiologist agreement of the site of transition zone on contrast enema was 90.6%. The concordance between the radiographic transition zone and pathologic extent of aganglionic bowel was 62.5%. The subgroup of patients with long-segment HD revealed a concordance of only 25%. Conclusion: Contrast enema delineation of the transition zone in HD needs to be regarded with caution. This is especially true in long-segment disease, where knowledge of the extent of aganglionic bowel is most crucial to surgical planning.

Splanchnic artery pseudo-aneurysms secondary to blunt abdominal trauma in children

Traumatic splanchnic artery pseudo-aneurysms are uncommon; only two cases have been reported among the pediatric population. The authors describe their experience with four patients in whom splanchnic artery pseudoaneurysms developed after blunt abdominal trauma. Splenic artery pseudo-aneurysms were found in a 6-year-old boy and an 8-year-old girl after blunt splenic injuries. In both cases, spontaneous thrombosis of the pseudo-aneurysms occurred after a period of observation. Hepatic artery pseudoaneurysms were found in a 7-year-old boy and a 10-year-old girl after major liver lacerations. The boy had successful angiographic embolization of the lesion, but the girl required direct ligation of the pseudo-aneurysm after nearly exsanguinating from acute hemorrhage. All four children have recovered completely, with no long-term sequelae. Traumatic splanchnic artery pseudo-aneurysms are potentially life-threatening complications that can occur after blunt abdominal trauma. The investigation and management of these lesions must be individualized according to the clinical scenario.

Giant hydatid lung cysts in the Canadian northwest: Outcome of conservative treatment in three children☆

Hydatid lung disease due to Echinococcus granulosus in the Canadian northwest and Alaska is often asymptomatic and usually benign. We reviewed the course and outcome of three children with giant hydatid lung cyst seen over a 2-year period. All were North American Indian children aged 9 to 12 years who presented with cough, fever, and chest pain. One had a rash. There was a history of exposure to domestic dogs who had been fed moose entrails in each case. Chest x-rays showed solitary lung cysts with air-fluid levels, from 6 cm to 12 cm in diameter. Aspiration of each cyst demonstrated Echinococcus hooklets and protoscolices. Serology was unhelpful, being negative in two cases. Transient pneumonitis and pneumothorax were seen as complications of needle aspiration. Two cysts gradually resolved over the following 6 months. One child returned after 9 months with a lung abscess due to superimposed infection of the cyst remnant with Haemophilus influenzae, and eventually required lobectomy. The existence of an endemic benign variant of E granulosus in Canada is not widely known, and it is important to distinguish it from the more aggressive pastoral form of the disease seen in immigrants from sheep-rearing countries. The native Canadian disease usually resolves spontaneously, does not cause anaphylaxis, and does not implant daughter cysts if spilled. Surgical treatment should be avoided except for complications such as secondary bacterial infection.

Topical mitomycin-C for recalcitrant esophageal strictures: a novel endoscopic/fluoroscopic technique for safe endoluminal delivery

BACKGROUND Nonsurgical treatment of recalcitrant pediatric esophageal strictures is challenging. The chemotherapy drug mitomycin-C, which reduces collagen synthesis and scar formation, shows anecdotal promise in the topical treatment of these strictures. Mitomycin-C is cytotoxic, and a safe endoluminal delivery system that avoids inadvertent application to adjacent mucosa has not yet been described. DISCUSSION We have treated 2 patients with a combined endoscopic/fluoroscopic technique that ensures protected delivery of a mitomycin-soaked pledget directly to the targeted site. Following pneumatic balloon dilation of the stricture under fluoroscopy, flexible esophagoscopy is performed to the disrupted stricture. Through the gastrostomy tract, a 12F to 16F semirigid sheath is introduced over a guide wire and passed retrograde up the esophagus to the stricture. A grasping forceps introduced through the instrument channel of the esophagoscope is advanced through the sheath and grasps a mitomycin-C-soaked pledget. The pledget is drawn back through the sheath up to the stricture where timed, serial radial applications to the stricture are performed without any contamination of the rest of the esophagus or stomach. CONCLUSION We describe a novel technique of endoluminal delivery and focused application of mitomycin-C to an esophageal stricture that avoids inadvertent topical application to adjacent mucosa.