Imaging of neuroblastoma and Wilms' tumor

Direct correlation of MRI with histopathology in pediatric renal tumors through the use of a patient-specific 3-D-printed cutting guide: a feasibility study

BACKGROUND

Pediatric renal tumors are often heterogeneous lesions with variable regions of distinct histopathology. Direct comparison between in vivo imaging and ex vivo histopathology might be useful for identification of discriminating imaging features.

OBJECTIVE

This feasibility study explored the use of a patient-specific three-dimensional (3D)-printed cutting guide to ensure correct alignment (orientation and slice thickness) between magnetic resonance imaging (MRI) and histopathology.

MATERIALS AND METHODS

Before total nephrectomy, a patient-specific cutting guide based on each patient's preoperative renal MRI was generated and 3-D printed, to enable consistent transverse orientation of the histological specimen slices with MRI slices. This was expected to result in macroscopic slices of 5 mm each. The feasibility of the technique was determined qualitatively, through questionnaires administered to involved experts, and quantitatively, based on structured measurements including overlap calculation using the dice similarity coefficient.

RESULTS

The cutting guide was used in eight Wilms tumor patients receiving a total nephrectomy, after preoperative chemotherapy. The median age at diagnosis was 50 months (range: 4-100 months). The positioning and slicing of the specimens were rated overall as easy and the median macroscopic slice thickness of each specimen ranged from 5 to 6 mm. Tumor consistency strongly influenced the practical application of the cutting guide. Digital correlation of a total of 32 slices resulted in a median dice similarity coefficient of 0.912 (range: 0.530-0.960).

CONCLUSION

We report the feasibility of a patient-specific 3-D-printed MRI-based cutting guide for pediatric renal tumors, allowing improvement of the correlation of MRI and histopathology in future studies.

Photodynamic Therapy in Complex Therapy of Retroperitoneal Tumors in Children

During the period from 2009 to 2021, 93 patients aged 0–11 years (48 boys and 45 girls) with retroperitoneal tumors were treated. There were 66 patients with nephroblastoma and 27 patients with adrenal neuroblastoma among them. As per treatment strategies, the patients were separated into two groups: the control group and the study group. The control group (comparison) received therapy according to the protocols, whereas the study group consisted of patients who received photodynamic therapy (PDT) in addition to the standard treatment. The control group consists of 47 patients with retroperitoneal tumors, including 35 patients with nephroblastoma and 12 patients with adrenal neuroblastoma. The study group included 46 children: 31 patients with nephroblastoma and 15 patients with adrenal neuroblastoma. The 5-year survival rate in the control group was 74.5%, and it was 91.3% in the study group (p = 0.030). Recurrent tumors developed in 14.9% of the patients in the control group, while in the study group, relapse occurred in 8.7% of the patients (p = 0.357). The PDT used in this study for treatment of retroperitoneal tumors improves the results of surgical treatment. It also appreciably increases the survival rate of patients with retroperitoneal tumors. Overall, PDT is a hopeful antitumor approach and can be effectively used in the complex therapy of retroperitoneal tumors in children.

High-Risk Neuroblastoma: Poor Outcomes Despite Aggressive Multimodal Therapy

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Neuroblastoma (NBL) is a highly malignant embryonal tumor that originates from the primordial neural crest cells. NBL is the most common tumor in infants and the most common extracranial solid tumor in children. The tumor is more commonly diagnosed in children of 1-4 years of age. NBL is characterized by enigmatic clinical behavior that ranges from spontaneous regression to an aggressive clinical course leading to frequent relapses and death. Based on the likelihood of progression and relapse, the International Neuroblastoma Risk Group classification system categorized NBL into very low risk, low risk, intermediate risk, and high risk (HR) groups. HR NBL is defined based on the patient's age (> 18 months), disease metastasis, tumor histology, and MYCN gene amplification. HR NBL is diagnosed in nearly 40% of patients, mainly those > 18 months of age, and is associated with aggressive clinical behavior. Treatment strategies involve the use of intensive chemotherapy (CTR), surgical resection, high dose CTR with hematopoietic stem cell support, radiotherapy, biotherapy, and immunotherapy with Anti-ganglioside 2 monoclonal antibodies. Although HR NBL is now better characterized and aggressive multimodal therapy is applied, the outcomes of treatment are still poor, with overall survival and event-free survival of approximately 40% and 30% at 3-years, respectively. The short and long-term side effects of therapy are tremendous. HR NBL carries a high mortality rate accounting for nearly 15% of pediatric cancer deaths. However, most mortalities are attributed to the high frequency of disease relapse (50%) and disease reactiveness to therapy (20%). Newer treatment strategies are therefore urgently needed. Recent discoveries in the field of biology and molecular genetics of NBL have led to the identification of several targets that can improve the treatment results. In this review, we discuss the different aspects of the epidemiology, biology, clinical presentations, diagnosis, and treatment of HR NBL, in addition to the recent developments in the management of the disease.

Extraosseous Ewing's Sarcoma: Pictorial Review of Imaging Findings, Differential Diagnosis, and Pathologic Correlation

Extraosseous Ewing's sarcoma (EES), first described in 1969, is a malignant mesenchymal tumor just like its intraosseous counterpart. Although Ewing's sarcomas are common bone tumors in young children, EESs are rarer and more commonly found in older children/adults, often carrying a poorer prognosis. We discuss the multimodality imaging features of EES and the differential diagnosis of an aggressive appearing mass in proximity to skeletal structures, with pathologic correlates. This review highlights the need to recognize the variability of radiologic findings in EES such as the presence of hemorrhage, rich vascularity, and cystic or necrotic regions and its imaging similarity to other neoplasms that are closely related pathologically.

Disorders of neural crest derivates in oncoradiological practice

Hundreds of articles discuss the imaging characteristics and molecular background of prominent gastrointestinal (GI) motility disorders and tumors of the peripheral nervous system, but according to our knowledge an article focusing on the classification and developmental background of these heterogeneous diseases is not to be found. Our aim is to give insight on the common features of several diseases and tumors, starting with their common source of origin, the neural crest (NC). The NC is a transient cell population of the embryo, which differentiates into several organs/structures of our body (sympathetic trunk, adrenal medulla). Although the incidence of the individual tumors of NC cells is not high by themselves, the summation of these incidences may be relevant in the daily routine. In the introduction we mention the most prominent developmental routes and molecular pathways of NC cells, which is crucial to understand the pathogenesis and the wide range of involved cell types from the colon to the adrenal gland. We summarized the most important, useful pathological findings and imaging techniques from the X-ray to the positron emission tomography—computed tomography (CT) in order to help the identification of these diseases. This article may help to better understand NC lineage and its unique, diverse role during ontogeny, which may influence the radiologists to change several convictions, or understand better the background and/or connections of a wide range of tumors and syndromes.

Diffusion-weighted MRI and intravoxel incoherent motion model for diagnosis of pediatric solid abdominal tumors

Background

Pediatric retroperitoneal tumors in the renal bed are often large and heterogeneous, and their diagnosis based on conventional imaging alone is not possible. More advanced imaging methods, such as diffusion‐weighted (DW) MRI and the use of intravoxel incoherent motion (IVIM), have the potential to provide additional biomarkers that could facilitate their noninvasive diagnosis.

Purpose

To assess the use of an IVIM model for diagnosis of childhood malignant abdominal tumors and discrimination of benign from malignant lesions.

Study Type

Retrospective.

Population

Forty‐two pediatric patients with abdominal lesions (n = 32 malignant, n = 10 benign), verified by histopathology.

Field Strength/Sequence

1.5T MRI system and a DW‐MRI sequence with six b‐values (0, 50, 100, 150, 600, 1000 s/mm²).

Assessment

Parameter maps of apparent diffusion coefficient (ADC), and IVIM maps of slow diffusion coefficient (D), fast diffusion coefficient (D*), and perfusion fraction (f) were computed using a segmented fitting model. Histograms were constructed for whole‐tumor regions of each parameter.

Statistical Tests

Comparison of histogram parameters of and their diagnostic performance was determined using Kruskal–Wallis, Mann–Whitney U, and receiver‐operating characteristic (ROC) analysis.

Results

IVIM parameters D* and f were significantly higher in neuroblastoma compared to Wilms' tumors (P < 0.05). The ROC analysis showed that the best diagnostic performance was achieved with D* 90^th percentile (area under the curve [AUC] = 0.935; P = 0.002; cutoff value = 32,376 × 10⁻⁶ mm²/s) and f mean values (AUC = 1.00; P < 0.001; cutoff value = 14.7) in discriminating between neuroblastoma (n = 11) and Wilms' tumors (n = 8). Discrimination between tumor types was not possible with IVIM D or ADC parameters. Malignant tumors revealed significantly lower ADC, D, and higher D* values than in benign lesions (all P < 0.05).

Data Conclusion

IVIM perfusion parameters could distinguish between malignant childhood tumor types, providing potential imaging biomarkers for their diagnosis.

Level of Evidence: 4

Technical Efficacy: Stage 2

J. Magn. Reson. Imaging 2018;47:1475–1486.

Neonatal neuroblastoma with adrenal primary and metastasis to the liver: A case report and a review of literature

We report the case of a 23-day-old neonate with neuroblastoma (NBL) in the right adrenal gland and widespread metastases to the liver. This raises the possibility of foetal NBL, which was missed during periodic ultrasonography done during the mother's pregnancy. We hope that this report would increase the awareness of physicians about foetal, congenital and neonatal NBL; and of sonographers about space-occupying lesions in the foetus. The clinicopathologic features and the management of neonatal NBL are discussed.

The standardized histogram shift of t2 magnetic resonance image (MRI) signal intensities of nephroblastoma does not predict histopathological diagnostic information

The objective of this study is to assess standardized histograms of signal intensities of T2-weighted magnetic resonance image (MRI) modality before and after preoperative chemotherapy for nephroblastoma (Wilms' tumor). All analyzed patients are enrolled in the International Society of Paediatric Oncology (SIOP) 2001/GPOH trial.1 The question to be answered is whether the comparison of the histograms can add new knowledge by comparing them with the histology of the tumor after preoperative chemotherapy. Twenty-three unilateral nephroblastoma cases were analyzed. All patients were examined by MRI before and after preoperative chemotherapy treatment. T2 modalities of the MRIs were selected, and histogram changes were compared to histopathological data available after surgery. Of the 23 tumors, 22 decreased in volume following chemotherapy (median -57.99%; range 15.65 to -90.82%). The preliminary results suggest that standardized histograms of signal intensities of T2 MRI in nephroblastoma is not predicting histopathological diagnostic information and has no implications for the clinical assessment for further chemotherapy.

[Nephrogenic tumors]

Nephroblastomas are the most common malignant renal tumors in childhood. According to the guidelines of the SIOP (Société Internationale d'Oncologie Pédiatrique) and GPOH (Gesellschaft für Pädiatrische Onkologie und Hämatologie) pre-operative chemotherapy can be started without histological confirmation and thus initial imaging studies, in particular ultrasound, play an outstanding role for diagnostic purposes.

Role of MRI in the management of patients with nephroblastoma

Magnetic resonance imaging (MRI) presents the main diagnostic tool for differentiation and staging of renal tumors in childhood. Nephroblastoma is the most common malignant tumor in children. Radiological findings play an important role in therapy study trials of SIOP (International Society of Pediatric Oncology), especially for indicating preoperative chemotherapy. In the past few years MRI has gained great importance in imaging of nephroblastoma and has replaced computed tomography (CT). The aim of this review is to present the diagnostic possibilities of MRI in relation to the requirements of therapy studies. For nephroblastoma, MRI provides important information about tumor extent and distant metastasis. A special focus of MRI in distant staging is venous extent of the tumor into the inferior vena cava. In addition, MRI has an important role in monitoring chemotherapy and in preoperative planning by volume rendering and three-dimensional postprocessing.

[Wilms' tumor in adults]

BACKGROUND

Wilms' tumor (nephroblastoma) is the most frequent renal tumor in childhood. In contrast nephroblastoma in adults is rare, and the disease used to have a poor prognosis.

PATIENTS AND METHODS

Of 1,300 registered patients, a total of 41 patients older than 16 years were enrolled in the pediatric nephroblastoma trial from 1994 to 2005. Median age at diagnosis was 25.4 years (range: 16-62 years). Treatment was given according to the pediatric protocol.

RESULTS

The adults had higher local stages, more frequent metastasis, and developed more toxicity due to therapy. Vincristine caused severe neurotoxicity in many cases. The distribution of histological subtypes was similar to the children's. The outcome is better than previously described with an overall survival of 71%. Patients with local stage I and II have an event-free survival of 84%. This is comparable to children's survival rates.

CONCLUSION

Adults with nephroblastoma have a very good prognosis if treated according to a pediatric protocol.

Neuroblastoma in childhood: review and radiological findings

The natural history, biologic and histological features, and the presenting symptoms of neuroblastoma are reviewed. The radiological findings of this neurogenic paediatric tumour are discussed.

[Radiologic differentiation of rhabdoid tumor from Wilms' tumor and mesoblastic nephroma]

Differentiation between rhabdoid tumor (RT) and mesoblastic nephroma (MN) and Wilms' tumor (WT) by imaging studies in babies and young children before histological confirmation is useful to start optimal treatment early. Typical radiologic criteria (crescent-shaped subcapsular liquid areas, tumor lobules, blurred tumor borders, metastasis in the lung, and regional lymph nodes) are described. The results of 26 MRI, 30 CT, and 22 ultrasound examinations of 49 patients (22 RT, 19 WT, and 8 MN, age 2-57 months) were analyzed. The above-mentioned radiologic criteria were classified with score values. The score value distribution was analyzed between the tumor entities and by two investigators.RT had significantly higher score values than the MN and WT. The difference between the two investigators was not significant. As a group RT differentiates from the group of WT and MN, but this is not possible in single cases with the radiologic criteria employed. Only if more signs are observed together in one case can a RT be presumed, which may indicate an early biopsy before chemotherapy.

Wilms' tumor in adults: results of the Society of Pediatric Oncology (SIOP) 93-01/Society for Pediatric Oncology and Hematology (GPOH) Study

PURPOSE

In the Society of Pediatric Oncology (SIOP) 93-01 study, 30 patients older than 16 years were found to have Wilms' tumor. They were treated according to the pediatric protocol and were analyzed for clinical presentation, stage distribution, and prognosis.

PATIENTS AND METHODS

Patient age ranged from 16 to 62 years (median, 25.4 years). Tumor stages were defined according to SIOP, and treatment was risk-adapted according to SIOP 93-01/Society for Pediatric Oncology and Hematology (GPOH) protocol. The patients were evaluated with regard to response, toxicity, and prognosis. Specimens of all tumors were centrally reviewed.

RESULTS

Ten patients (33%) had metastatic disease at the time of diagnosis (liver, four patients; lung, three patients; liver and lung, three patients). The local stage distribution showed a predominance of higher stages (stage I, eight patients; stage IIN-, three patients; stage IIN+, four patients; stage III, 15 patients). Histologic studies revealed intermediate-risk in 23 of 30 tumors; two tumors were classified as high-risk; and three tumors were clear-cell sarcomas. Two of 30 patients showed a nephroblastoma and a renal cell carcinoma simultaneously in the same kidney. A complete remission was achieved in 24 patients; four patients relapsed after complete remission; and three of them reached a second remission with further treatment. Event-free survival was 57%, with an overall survival of 83% (median observation time, 4 years).

CONCLUSION

Adults can be cured in a high percentage by a multimodal treatment according to pediatric protocols. Toxicity is higher than in children, but acceptable in view of the high remission rate.