Background and Aims

In pediatric renal tumors there is no histopathological assessment until after surgery. Imaging could play a crucial role in the pre-operative characterization of renal tumor types. Direct correlation of radiology and pathology could reveal imaging features in these frequently highly heterogeneous lesions. With this pilot study the feasibility of a patient-specific 3D-printed cutting guide is investigated to ensure corresponding orientation between magnetic resonance imaging (MRI) and histopathology.

Methods

Based on the preoperative MRI-scan prior to total nephrectomy, a 3D-model of the kidney and tumor was manually developed in 3D Slicer. This allowed us to create a cutting guide enabling an MRI-orientated transversal slicing of the specimen. The pathologist used the cutting guide for gross dissection of the specimen, ensuring macroscopic slices of 5 millimeters each. The feasibility of this technique was determined using structured measurements including overlap calculation with the dice similarity coefficient and qualitatively through questionnaires among involved experts.

Results

In this pilot, the cutting guide has been applied to seven patients with Wilms tumor. Their median age at diagnosis was 50months (range 4-100 months). Digital correlation in a total of 28 slices resulted in a median dice similarity coefficient of 0.91 (range 0.53-0.97). The positioning and slicing of the specimen was overall rated as ‘easy’ and the median macroscopic slice thickness of each specimen ranged from 5-6 millimeters. Tumor consistency strongly influenced the practical application of the cutting guide.

Conclusions

A patient-specific 3D-printed cutting guide seems to provide a feasible tool for the direct correlation of MRI and histopathology of pediatric renal tumors. The clinical implementation and design of the cutting guide are currently optimized, to ensure a methodological workflow for future prospective studies.

Background and Aims

During surgery for pediatric neoplastic diseases, an identification of small tumor lesions or vital neurovascular bundles is often difficult. In this study, we reviewed our experience of navigation surgery for these diseases.

Methods

From 2002 to 2020, 8 patients underwent navigation surgery. They included 1 with intrahepatic lesion and 2 with lung metastases of hepatoblastoma, 1 with recurrent thyroid medullary carcinoma (MTC), 1 with ectopic parathyroid in the mediastinum, and 3 with cervical lymphangioma.

Results

Fluoroscopy-aided resection with preoperative lipiodol-marking was performed for lung metastasis of hepatoblastoma. Although the pulmonary nodule was identified easily, it required CT-guided injection just before surgery under general anesthesia. From 2017, fluorescence-guided surgery using indocyanine green (ICG) fluorescence imaging system (PDE®) was introduced for hepatoblastoma and its lung metastasis. PDE clearly visualized the lesions in the liver or on the surface of the lung, except the lesion at a depth of over 1cm. Radio-guided surgery using gamma radiation detector (Navigator system GPS®) with preoperative radioisotope injection was performed for MTC (¹²³I-MIBG) and ectopic parathyroid (^99mTc-sestamibi), and high scintillation counting spot was well noted at the lesion site. Nerve monitoring system (NIM®) was useful to preserve facial nerve during debulking surgery for cervical lymphangioma.

Conclusions

Navigation surgery for pediatric oncologic disorders are still developing, but promising techinique. Intraoperatve navigation using various modalities based on the physiological specificity of diseases makes surgery safer and curative.

Background and Aims

Background: Retinoblastoma is the most frequent intraocular malignancy of childhood. Transpupillary thermotherapy is one of the main methods of small retinoblastoma treatment. However, only a few studies have been published on the use of transpupillary thermotherapy in children with retinoblastoma and these publications are devoted to the certain aspects of the application of this method.

Aim: To evaluate the efficacy of transpupillary thermotherapy for retinoblastoma.

Methods

In a retrospective study, we reviewed case series of 177 children with retinoblastoma (1156 tumors in 224 eyes) treated with transpupillary thermotherapy at the S. Fyodorov Eye Microsurgery Federal State Institution in Moscow between October 2011 and December 2020. The median patient age at the time of treatment was 16.8 months. The mean tumor thickness was 1.1 mm (from 0.2 to 4.5), the mean basal diameter was 2.2 mm (from 0.3 to 13.4). Transpupillary thermotherapy was performed using a diode laser with the following parameters: wave length-810 nm, spot diameter-1200 microns, power from 200 to 800 mW (mean - 350 mW), exposure-from 3 to 15 s in the application mode, and continuous in the scanning mode.

Results

Overall tumor control was achieved in 92.7% (1072 tumors). Tumor recurrence was observed in 7% (82 tumors) and these tumors were treated with other local methods. 209 eyes (93%) were preserved. 15 eyes (7%) were enucleated due to tumor progression, total retinal detachment, vitreous hemorrhage or subatrophy of the eyeball. Complications after transpupillary thermotherapy included local vitreous hemorrhage (2 eyes; 0.9%), pretumoral hemorrhage (3 eyes, 1.3%), local vitreous opacities (2 eyes; 0.9%), iris atrophy and anterior synechiae (1 eye, 0.45%). The median follow-up was 35.5 months.

Conclusions

Transpupillary thermotherapy is an effective treatment for retinoblastoma with excellent local tumor control and few complications.

Background and Aims

Complete upfront resection of pediatric gastrointestinal lymphomas is recommended over biopsy whenever feasible, but either approach may have adverse sequelae. We sought to compare gastrointestinal and oncological outcomes of pediatric gastrointestinal lymphomas who underwent attempted upfront resection or biopsy of the presenting bowel mass.

Methods

We retrospectively reviewed charts of children with gastrointestinal non-Hodgkin lymphomas treated on LMB89 and LMB96 protocols at KK Women's and Children's Hospital from 2000–2019 who underwent upfront gastrointestinal surgery, and compared resection and biopsy groups.

Results

Of 33 children with abdominal lymphomas, 20 had upfront gastrointestinal surgery – 10 each had resection or biopsy. Most had Burkitt lymphoma (n=18 (90%)). The resection group included 6 hemi-colectomies for irreducible intussusception, 2 ileal resections and 2 appendectomies. The biopsy group included 6 laparoscopic, 3 open and 1 percutaneous procedures. Patients with resections had fewer postoperative gastrointestinal complications compared to biopsies (10% vs. 60%, p=0.057), but significantly longer time to chemotherapy initiation (median 11.5 vs. 4.5 days, p<0.001), with only 3 resection patients successfully down-staged surgically. Despite this, relapse and survival outcomes did not differ significantly between biopsy and resection groups, though was better with LMB96 protocol with stage II/III disease. Second surgeries were required in 30% and 40% of resected and biopsied patients, respectively, at median 4.6 months, with all 4 patients in the biopsy group requiring resection and anastomosis at their previously diseased bowel segments for strictures or suspected residual disease.

Conclusions

Children with upfront resection had low rates of surgical downstaging and greater delay in chemotherapy initiation than those with biopsies, but fewer gastrointestinal complications and subsequent surgeries. This suggests that while surgeons overestimate the likelihood of complete upfront disease clearance, the similar survival rates regardless of upfront surgery reflect the beneficial effects of newer protocols. Nevertheless, second surgeries are still frequently required, even after completion of therapy.