Comparative study of FDG PET/CT and conventional imaging in the staging of rhabdomyosarcoma

Pleomorphic rhabdomyosarcoma in adults: a case report

BACKGROUND

Rhabdomyosarcoma is a rare type of soft-tissue sarcoma that is more frequently observed in children and is less common in adults. Rhabdomyosarcoma can occur in any part of the body, including tissues without skeletal muscles. The main subtypes of rhabdomyosarcoma are embryonal, alveolar, and pleomorphic. Pleomorphic rhabdomyosarcoma is a rare variant typically found in adults over 45 years old and is characterized by early metastasis.

CASE PRESENTATION

This article reports a rare case of primary pleomorphic rhabdomyosarcoma in the duodenum of A 67-year-old Iranian male. The patient presented to the hospital with epigastric pain and severe anemia. Abdominal imaging revealed a polypoid mass in the duodenum and antropyloric region of the stomach. Laboratory tests confirmed severe anemia, and an endoscopic biopsy initially misdiagnosed the mass as a poorly differentiated epithelioid gastrointestinal stromal tumor.

CONCLUSION

Following surgery and comprehensive immunohistochemical analysis, the final diagnosis of primary pleomorphic rhabdomyosarcoma in the duodenum was confirmed. This case highlights the diagnostic challenges associated with pleomorphic rhabdomyosarcoma in the gastrointestinal tract and underscores the importance of comprehensive immunohistochemical analysis for accurate diagnosis. The article emphasizes the need for further research to better understand the clinical behavior and optimal management of primary gastrointestinal pleomorphic rhabdomyosarcoma.

Molecular Imaging with PET-CT and PET-MRI in Pediatric Musculoskeletal Diseases

Molecular imaging has emerged as an integral part of oncologic imaging. Given the physiologic changes that precede anatomic changes, molecular imaging can enable early detection of disease and monitoring of response. [18F] Fluorodeoxyglucose (FDG) Positron emission tomography (PET) is the predominant molecular imaging modality used in oncologic assessment and can be performed using PET/CT or PET/MR. In pediatric patients, PET/MRI imaging is generally preferred due to low radiation exposure and PET/MRI is particularly advantageous for imaging musculoskeletal (MSK) diseases, as MRI provides superior characterization of tissue changes as compared to CT. In this article, we provide an overview of the typical role of PET CT/MRI in assessment of some common pediatric malignancies and benign MSK diseases with case examples. We also discuss the relative advantages of PET/MRI compared to PET/CT, and review published data with a primary focus on the use of PET/MR.

Positron Emission Tomography/Computed Tomography Transformation of Oncology: Musculoskeletal Cancers

The past 25 years have seen significant growth in the role of positron emission tomography/computed tomography (PET/CT) in musculoskeletal oncology. Substantiative advances in technical capability and image quality have been paralleled by increasingly widespread clinical adoption and implementation. It is now recognized that PET/CT is useful in diagnosis, staging, prognostication, response assessment, and surveillance of bone and soft tissue sarcomas, often providing critical information in addition to conventional imaging assessment. As individualized, precision medicine continues to evolve for patients with sarcoma, PET/CT is uniquely positioned to offer additional insight into the biology and management of these tumors.

Distant metastasis of alveolar rhabdomyosarcoma with pancreatic parameningeal localization in children: clinical case series

Rhabdomyosarcoma is a malignant neoplasm that develops from embryonic mesenchymal cells, with an annual incidence of 4.3 cases per 1,000,000 children. The prevalence of the tumor process is estimated on the basis of data from a comprehensive examination, including magnetic resonance imaging with intravenous contrast, ultrasound examination of the primary focus of regional and distant metastasis zones, computed tomography and radioisotope studies. The overall 5-year survival rate for localized rhabdomyosarcoma reaches 70 %. During the initial diagnosis, distant metastasis to the lungs, bones, and bone marrow is detected, which significantly worsens the prognosis in 20–25 % of patients. The factors of an extremely unfavorable prognosis for the course of alveolar rhabdomyosarcoma are the occurrence of regional and distant metastases before the start of specific treatment, dissemination of the tumor lesion during treatment, and the presence of translocation of the 13q14 sector. Publications contain data on a high (11.2 %) prevalence of metastases of alveolar rhabdomyosarcoma in the pancreas. In the presence of metastatic lesions of the pancreas, surgical treatment is effective only in combination with chemoradiotherapy. Long-term results of treatment of this cohort of children are unsatisfactory due to the high risk of recurrence and dissemination of the tumor.

Aim. To study risk factors, evaluate methods and prospects for the treatment of children with metastatic pancreatic lesions in parameningeal alveolar rhabdomyosarcoma. The article considers three clinical cases of such a lesion. We would like to draw the attention of pediatric oncologists and radiologists to the possible association of metastases in the pancreas in children with localization of rhabdomyosarcoma in the head and neck region, which requires improvement of examination protocols in this group of patients.

Molecular imaging of sarcomas with FDG PET

Sarcoma comprises a heterogenous entity of musculoskeletal malignancies arising from a mesenchymal origin. The diagnosis and management of pediatric sarcoma requires a multidisciplinary approach and the use of various imaging modalities including CT, MRI and FDG PET scans. FDG PET/CT (FDG PET), as a metabolic imaging, complements and provides superior diagnostic information as against other imaging modalities alone. Advantages of FDG PET in differentiating malignant sarcomatous lesions from benign lesions, and value in staging and restaging have been noted in several studies. The use of FDG PET in clinical management has increased over the years. The data on prognostication of outcomes or predicting responders to therapy with FDG PET in patients with sarcoma is somewhat limited. This review will focus on the pearls and pitfalls of FDG PET and role of FDG PET in initial extent of disease assessment, treatment response, and surveillance imaging pertaining to osteosarcoma, chondrosarcoma, Ewing's sarcoma, and rhabdomyosarcoma. We also discuss the limitations and unmet needs of FDG PET in the management of patients with sarcoma.

Fisher discriminant model based on LASSO logistic regression for computed tomography imaging diagnosis of pelvic rhabdomyosarcoma in children

Computed tomography (CT) has been widely used for the diagnosis of pelvic rhabdomyosarcoma (RMS) in children. However, it is difficult to differentiate pelvic RMS from other pelvic malignancies. This study aimed to analyze and select CT features by using least absolute shrinkage and selection operator (LASSO) logistic regression and established a Fisher discriminant analysis (FDA) model for the quantitative diagnosis of pediatric pelvic RMS. A total of 121 pediatric patients who were diagnosed with pelvic neoplasms were included in this study. The patients were assigned to an RMS group (n = 36) and a non-RMS group (n = 85) according to the pathological results. LASSO logistic regression was used to select characteristic features, and an FDA model was constructed for quantitative diagnosis. Leave-one-out cross-validation and receiver operating characteristic (ROC) curve analysis were used to evaluate the diagnostic ability of the FDA model. Six characteristic variables were selected by LASSO logistic regression, all of which were CT morphological features. Using these CT features, the following diagnostic models were established: (RMS group)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${G}_{1}=-14.283+6.613{x}_{1}+5.333{x}_{2}+5.753{x}_{3}+12.361{x}_{4}+8.095{x}_{5}-0.715{x}_{6}$$\end{document}G1=-14.283+6.613x1+5.333x2+5.753x3+12.361x4+8.095x5-0.715x6; (Non-RMS group)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${G}_{2}=-2.008+3.539{x}_{1}+1.080{x}_{2}+1.154{x}_{3}+2.307{x}_{4}+1.656{x}_{5}+1.380{x}_{6}$$\end{document}G2=-2.008+3.539x1+1.080x2+1.154x3+2.307x4+1.656x5+1.380x6, where \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${x}_{1}$$\end{document}x1, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${x}_{2}$$\end{document}x2, … and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${x}_{6}$$\end{document}x6 are lower than normal muscle density (1 = yes; 0 = no), multinodular fusion (1 = yes; 0 = no), enhancement at surrounding blood vessels (1 = yes; 0 = no), heterogeneous progressive centripetal enhancement (1 = yes; 0 = no), ring enhancement (1 = yes; 0 = no), and hemorrhage (1 = yes; 0 = no), respectively. The calculated area under the ROC curve (AUC) of the model was 0.992 (0.982–1.000), with a sensitivity of 94.4%, a specificity of 96.5%, and an accuracy of 95.9%. The calculated sensitivity, specificity and accuracy values were consistent with those from cross-validation. An FDA model based on the CT morphological features of pelvic RMS was established and could provide an easy and efficient method for the diagnosis and differential diagnosis of pelvic RMS in children.

Primary rhabdomyosarcoma of the ethmoid sinus with orbital extension and metastasis to the pancreatic body

This case report highlights the need for clinicians to monitor patients with rhabdomyosarcoma for pancreatic metastasis to ensure that proper treatment is quickly provided, thereby improving outcomes.

PET-CT in Clinical Adult Oncology-VI. Primary Cutaneous Cancer, Sarcomas and Neuroendocrine Tumors

PET-CT is an advanced imaging modality with many oncologic applications, including staging, therapeutic assessment, restaging and surveillance for recurrence. The goal of this series of six review articles is to provide practical information to providers and imaging professionals regarding the best use of PET-CT for specific oncologic indications, the potential pitfalls and nuances that characterize these applications, and guidelines for image interpretation. Tumor-specific clinical information and representative PET-CT images are provided. The current, sixth article in this series addresses PET-CT in an evaluation of aggressive cutaneous malignancies, sarcomas and neuroendocrine tumors. A discussion of the role of FDG PET for all types of tumors in these categories is beyond the scope of this review. Rather, this article focuses on the most common malignancies in adult patients encountered in clinical practice. It also focuses on Food and Drug Agency (FDA)-approved and clinically available radiopharmaceuticals rather than research tracers or those requiring a local cyclotron. This information will serve as a guide to primary providers for the appropriate role of PET-CT in managing patients with cutaneous malignancies, sarcomas and neuroendocrine tumors. The nuances of PET-CT interpretation as a practical guide for imaging providers, including radiologists, nuclear medicine physicians and their trainees, are also addressed.

Clinical group and modified TNM stage for rhabdomyosarcoma: A review from the Children's Oncology Group

The Children's Oncology Group (COG) uses Clinical Group (CG) and modified Tumor Node Metastasis (TNM) stage to classify rhabdomyosarcoma (RMS). CG is based on surgicopathologic findings and is determined after the completion of initial surgical procedure(s) but prior to chemotherapy and/or radiation therapy. The modified TNM stage is based on clinical and radiographic findings and is assigned prior to any treatment. These systems have evolved over several decades. We review the history, evolution, and rationale behind the current CG and modified TNM classification systems used by COG for RMS. Data from the seven most recently completed and reported frontline COG trials (D9602, D9802, D9803, ARST0331, ARST0431, ARST0531, ARST08P1) were analyzed, and confirm that CG and modified TNM stage remain relevant and useful for predicting prognosis in RMS. We propose updates based on recent data and discuss factors warranting future study to further optimize these classification systems.

Japanese Orthopaedic Association (JOA) clinical practice guidelines on the management of soft tissue tumors 2020 - Secondary publication

BACKGROUND

These clinical practice guidelines are intended to provide recommendations based on the best evidence obtained to date on key issues in clinical practice to improve the prognosis, diagnostic and therapeutic processes for patients with soft tissue tumors.

METHODS

The Guidelines Development Committee and Systematic Review Committee were composed of a multidisciplinary team of specialists who play an important role in soft tissue tumor care. Clinical questions (CQs) were determined by choosing key decision-making points based on Algorithms for the diagnosis and treatment of soft tissue tumors. The guidelines were developed according to the "Medical Information Network Distribution Service (Minds) Handbook for Clinical Practice Guideline Development 2014" and "Minds Manual for Clinical Practice Guideline Development 2017." Recommendation strength was rated on two levels and the strength of evidence was rated on four levels. The recommendations were decided based on agreement by 70% or more voters.

RESULTS

Twenty-two CQs were chosen by the Guidelines Development Committee. The Systematic Review Committee reviewed the evidence concerning each CQ, a clinical value judgment was added by experts, and the text of each recommendation was determined.

CONCLUSION

We established 22 CQs and recommendations for key decision-making points in the diagnosis and treatment of soft tissue tumors according to the Minds Clinical Practice Guideline development methods. We hope that these guidelines will assist the decision-making of all medical staff engaged in the treatment and diagnosis of soft tissue tumors, and eventually lead to improved soft tissue tumor care in the country.

Rhabdomyosarcoma in Adults: Case Series and Literature Review

Rhabdomyosarcoma, a common soft tissue malignant tumor in children and adolescents, is exceedingly rare in adults. Nevertheless, The outcome in adults is very poor, especially when compared to outcomes in children in whom significant improvements in treatment has been achieved. The first case was of a 24-year-old pregnant Chinese woman with a rare primary site of rhabdomyosarcoma in the perineal body. She presented with a perineal mass and was diagnosed during the second trimester of pregnancy, which is a very rare occurrence. The second case was a 70-year-old Chinese woman who suffered from right lower abdominal pain for 1 month and was misdiagnosed with an epithelial ovarian carcinoma. Mesenteric pleomorphic rhabdomyosarcoma was later confirmed by postoperative pathology. Both cases had undergone preoperative examination with chest and abdominal computed tomography (CT) and pelvic magnetic resonance imaging (MRI) examinations, as well as examination of complete blood count, liver panel, renal panel, and serum tumor markers. Diagnosis was based on histopathology and immunohistochemistry. The patient in the first case received chemotherapy after which the mass decreased in size; however, the patient was lost to follow-up. The second case underwent tumor resection and received chemotherapy and radiotherapy.

Contribution of positron emission tomography/magnetic resonance imaging in musculoskeletal malignancies

Positron emission tomography/computed tomography (PET/CT) is a promising hybrid imaging technique for evaluating musculoskeletal malignancies. Both technologies, independently are useful for evaluating this type of tumors. PET/MR has great potential combining metabolic and functional imaging PET with soft tissue contrast and multiparametric sequences of MR. In this paper we review the existing literature and discuss the different protocols, new available radiotracers to conclude with the scarce evidence available the most useful/probable indications of the PET MR for the for musculoskeletal malignancies.

Fluorine-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) computed tomography (CT) for the detection of bone, lung, and lymph node metastases in rhabdomyosarcoma

BACKGROUND

Rhabdomyosarcoma (RMS) is the most common paediatric soft-tissue sarcoma and can emerge throughout the whole body. For patients with newly diagnosed RMS, prognosis for survival depends on multiple factors such as histology, tumour site, and extent of the disease. Patients with metastatic disease at diagnosis have impaired prognosis compared to those with localised disease. Appropriate staging at diagnosis therefore plays an important role in choosing the right treatment regimen for an individual patient. Fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) is a functional molecular imaging technique that uses the increased glycolysis of cancer cells to visualise both structural information and metabolic activity. 18F-FDG-PET combined with computed tomography (CT) could help to accurately stage the extent of disease in patients with newly diagnosed RMS. In this review we aimed to evaluate whether 18F-FDG-PET could replace other imaging modalities for the staging of distant metastases in RMS.

OBJECTIVES

To determine the diagnostic accuracy of 18F-FDG-PET/CT imaging for the detection of bone, lung, and lymph node metastases in RMS patients at first diagnosis.

SEARCH METHODS

We searched MEDLINE in PubMed (from 1966 to 23 December 2020) and Embase in Ovid (from 1980 to 23 December 2020) for potentially relevant studies. We also checked the reference lists of relevant studies and review articles; scanned conference proceedings; and contacted the authors of included studies and other experts in the field of RMS for information about any ongoing or unpublished studies. We did not impose any language restrictions.

SELECTION CRITERIA

We included cross-sectional studies involving patients with newly diagnosed proven RMS, either prospective or retrospective, if they reported the diagnostic accuracy of 18F-FDG-PET/CT in diagnosing lymph node involvement or bone metastases or lung metastases or a combination of these metastases. We included studies that compared the results of the 18F-FDG-PET/CT imaging with those of histology or with evaluation by a multidisciplinary tumour board as reference standard.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, data extraction, and methodological quality assessement according to Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). We analysed data for the three outcomes (nodal involvement and lung and bone metastases) separately. We used data from the 2 × 2 tables (consisting of true positives, false positives, true negatives, and false negatives) to calculate sensitivity and specificity in each study and corresponding 95% confidence intervals. We did not consider a formal meta-analysis to be relevant because of the small number of studies and substantial heterogeneity between studies.

MAIN RESULTS

Two studies met our inclusion criteria. The diagnostic accuracy of 18F-FDG-PET/CT was reported in both studies, which included a total of 36 participants. We considered both studies to be at high risk of bias for the domain reference standard. We considered one study to be at high risk of bias for the domain index test and flow and timing. Sensitivity and specificity of 18F-FDG-PET/CT for the detection of bone metastases was 100% in both studies (95% confidence interval (CI) for sensitivity was 29% to 100% in study one and 40% to 100% in study two; 95% CI for specificity was 83% to 100% in study one and 66% to 100% in study two). The reported sensitivity of 18F-FDG-PET/CT for the detection of lung metastases was not calculated since only two participants in study two showed lung metastases, of which one was detected by 18F-FDG-PET/CT. Reported specificity was 96% in study one (95% CI 78% to 100%) and 100% (95% CI 72% to 100%) in study two. The reported sensitivity for the detection of nodal involvement was 100% (95% CI 63% to 100% in study one and 40% to 100% in study two); the reported specificity was 100% (95% CI 78% to 100%) in study one and 89% (95% CI 52% to 100%) in study two.

AUTHORS' CONCLUSIONS

The diagnostic accuracy of 18F-FDG-PET/CT for the detection of bone, lung, and lymph node metastases was reported in only two studies including a total of only 36 participants with newly diagnosed RMS. Because of the small number of studies (and participants), there is currently insufficient evidence to reliably determine the diagnostic accuracy of 18F-FDG-PET/CT in the detection of distant metastases. Larger series evaluating the diagnostic accuracy of 18F-FDG-PET/CT for the detection of metastases in patients with RMS are necessary.

Spectrum of Flurodeoxyglucose Positron Emission Tomography/Computerized Tomography Findings in Tumors and Tumor-Like Conditions of the Musculoskeletal System

Bone and soft-tissue tumors display a wide range of metabolic activity on flurodeoxyglucose positron emission tomography/computerized tomography (FDG PET/CT) imaging due to their varying histopathological features. Several benign tumors show high FDG uptake similar to that seen in malignant lesions and their metabolic characteristics can overlap. Certain benign tumors can potentially undergo malignant transformation and FDG PET/CT can play an important role in detecting malignant change. The intensity of metabolic activity on FDG PET/CT correlates with histological grade of malignant tumors and also acts as a valuable prognostic factor. FDG PET/CT plays an important role in the staging work up of bone and soft-tissue malignancies. It has been found to be superior to conventional imaging techniques primarily for detecting distant metastatic disease. Because of its ability to detect metabolic changes, FDG PET/CT is a very useful in assessing response to treatment. Metabolic response seen on FDG PET is a powerful surrogate marker of histopathological response to chemotherapy. The purpose of this article is to study the variable patterns of FDG uptake in tumors of the musculoskeletal system, describe the clinical utility of FDG PET/CT in predicting malignant change in benign tumors and discuss its role in staging, response assessment, and prognostication of malignant lesions.

Role of 18F-FDG-PET/CT in the staging of metastatic rhabdomyosarcoma: a report from the European paediatric Soft tissue sarcoma Study Group

BACKGROUND

Initial staging of rhabdomyosarcoma is crucial for prognosis and to tailor the treatment. The standard radiology workup (SRW) includes magnetic resonance imaging, chest computed tomography (CT) and bone scintigraphy, but 18 Fluorine-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) (¹⁸F-FDG-PET/CT (PET-CT)) use is increasing. The aim of this study was to evaluate the impact of PET-CT in the initial staging of patients with metastatic rhabdomyosarcoma enrolled in the European protocol MTS2008.

METHODS

Two authors retrospectively reviewed the SRW and PET-CT reports comparing the number and sites of metastases detected. For bone marrow involvement, PET-CT and bone marrow aspirates/biopsies were compared.

RESULTS

Among 263 metastatic patients enrolled from October 2008 to December 2016, 121 had PET-CT performed at diagnosis, and for 118 of 121 patients, both PET-CT and radiological reports were available for review. PET-CT showed higher sensitivity than SRW in the ability to detect locoregional (96.2% versus 78.5%, P value = 0.0013) and distant lymph node involvement (94.8% versus 79.3%, P value = 0.0242), but sensitivity was lower for intrathoracic sites (lung 79.6% versus 100%, P value = 0.0025). For bone metastasis, PET-CT was more sensitive than bone scintigraphy (96.4% versus 67.9%, P value = 0.0116). The PET-CT sensitivity and specificity to detect marrow involvement were 91.8% and 93.8%, respectively. The mean number of metastatic sites was 1.94 (range 0-5) with PET-CT and 1.72 (range 0-5) with SRW. In four patients (3.4%), PET-CT changed the staging from localised to metastatic disease.

CONCLUSION

PET can identify metastatic disease not evident on SRW in a small number of patients. This is because of its higher ability to recognise lymph node and bone involvement. Chest CT remains essential to detect lesions in intrathoracic sites, which can be performed in a one stop-shot routine examination or on a dedicated chest CT scan. PET-CT could replace bone scintigraphy to study bone involvement.

Testicular, Spermatic Cord, and Scrotal Soft Tissue Sarcomas: Treatment Outcomes and Patterns of Failure

INTRODUCTION

Paratesticular sarcomas are defined as tumors that arise within the scrotum and include the subsites of epididymis, spermatic cord, and tunica vaginalis and represent the most common type of GU sarcoma. The mainstay of treatment is often surgical resection, combined with histology specific chemotherapy and radiotherapy. Due to the rare nature of the disease, there are limited data to guide management. We present our single-institution retrospective experience regarding the management and treatment of paratesticular sarcomas.

MATERIALS AND METHODS

We queried our oncology registry database for patients treated for testicular, spermatic cord, and scrotal soft tissue sarcomas between 1971 and 2017. Patients in this series had pathological confirmation of a sarcoma diagnosis by a sarcoma-specialized pathologist. Only patients with localized disease were included in this analysis with the exception of patients with a diagnosis of rhabdomyosarcoma where patients with both localized and metastatic disease were included on this study.

RESULTS

A total of 34 patients were included in this retrospective analysis. The median was 24 (range, 5-78), and the median tumor size was 6.25 cm. Twenty-six patients had localized disease (76.6%) at the time of diagnosis. A predominance of patients had tumors involving the spermatic cord (45.5%), and the most common histology was rhabdomyosarcoma (35.3%), leiomyosarcoma (26.5%), and well-differentiated liposarcoma (23.5%). The median follow-up was 71.0 months (range, 2.5-534.4 months). A total of 7 patients experienced an isolated local failure (20.6%), four patients developed distant metastatic disease (11.8%), and one patient (2.9%) with synovial sarcoma of the spermatic cord experienced a regional recurrence. The median progression-free survival (PFS) was 99.6 months, 95% CI (45.8-534.3 months), with a three-year PFS rate of 71%, 95% CI (53%-83%), and a 5-year PFS rate of 64% (range, 46%-78%). We did not find any statistically significant associations based on surgery type (p=0.15), the use of chemotherapy, (p=0.36), or final margin status (p=0.21). Two patients who were treated with preoperative radiotherapy had significant wound healing complication with chronic sinus tracts, though these patients did not experience a local recurrence.

CONCLUSIONS

We provide a characterization of the natural history and treatment patterns of paratesticular sarcomas. While effective at reducing a local recurrence, preoperative radiotherapy was associated with significant toxicity. As a result, we prefer the use of postoperative radiotherapy in patients as clinically indicated. We did not find any specific treatment patterns associated with an improvement in clinical outcomes.

Update on pediatric rhabdomyosarcoma: A report from the APSA Cancer Committee

BACKGROUND/PURPOSE

Rhabdomyosarcoma is the most common soft tissue sarcoma in children and young adults and requires multimodality treatment. The purpose of this review is to present an update on risk stratification as well as surgical and medical management strategies in pediatric rhabdomyosarcoma.

METHODS

A comprehensive review of the current literature on pediatric rhabdomyosarcoma, including the most recent Children's Oncology Group studies and several international collaboratives, was performed by the authors and key findings were summarized in the manuscript.

RESULTS

FOXO1 fusion status is a stronger prognostic factor than histology and is now used for risk stratification in treatment protocols. For assessment of regional nodal involvement, FDG-PET-CT shows poor sensitivity and specificity to detect histologically confirmed nodal metastasis. Thus, surgical assessment of regional lymph nodes is required for rhabdomyosarcoma of the extremities or trunk as well as paratesticular rhabdomyosarcoma in patients ≥10 years of age, although adherence to surgical guidelines remains poor. Hemiscrotectomy performed for scrotal violation in paratesticular rhabdomyosarcoma has not shown an improvement in event free survival and is not recommended.

CONCLUSIONS

Surgical and medical treatment strategies for rhabdomyosarcoma in children continue to evolve. This review provides current evidence-based treatment standards with an emphasis on surgical care.

TYPE OF STUDY

Review.

LEVEL OF EVIDENCE

Level IV.

Quantitative Musculoskeletal Tumor Imaging

The role of quantitative magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) techniques continues to grow and evolve in the evaluation of musculoskeletal tumors. In this review we discuss the MRI quantitative techniques of volumetric measurement, chemical shift imaging, diffusion-weighted imaging, elastography, spectroscopy, and dynamic contrast enhancement. We also review quantitative PET techniques in the evaluation of musculoskeletal tumors, as well as virtual surgical planning and three-dimensional printing.

Utility of [18F] Fluoro-Deoxyglucose Positron Emission Tomography/Computed Tomography for Staging and Therapy Response Evaluation in Pediatric Rhabdomyosarcoma: A Case Series and Literature Review

Background: The role of [¹⁸F] fluoro-deoxyglucose [[¹⁸F] FDG] positron emission tomography (PET)/computed tomography (CT) in pediatric rhabdomyosarcoma (RMS) is not well-established. This manuscript explores the role of staging and therapy response evaluation of PET/CT in a series of patients with RMS.

Methods: Thirteen consecutive patients with pathologically proven RMS underwent baseline PET/CT scan and a second PET/CT for evaluation of therapy response. Maximum standardized uptake value (SUV_max), mean standardized uptake value (SUV_mean), highest standardized uptake peak value (SUV_peak), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were obtained from baseline PET/CT and were used as potential predictors for evaluation of metabolic treatment response.

Results: On baseline PET/CT, most RMSs are located in the pelvic cavity, and upper arms ranked second. The primary lesions were large and showed invasion to the surrounding tissues. Lymph node metastases were seen in eight patients, and eight patients showed distant metastasis to the lung, liver, and bone. The median SUV_max, SUV_mean, and SUV_peak of primary sites were 7.1, 4.0, and 5.9, respectively. The median MTV and TLG were 196.6 cm³ and 780.2, respectively. After therapy, six patients received complete metabolic response (CMR) and non-CMR occurred in seven patients on the second PET/CT. SUV_max, SUV_peak, MTV, and TLG in patients with CMR were significantly lower than those in patients with non-CMR.

Conclusions: Primary sites and metastatic lesions of RMS demonstrate increased glycolytic activity, which may allow them to be imaged using [¹⁸F] FDG PET/CT. Metabolic parameters derived from the baseline PET/CT have potential value for predicting CMR to therapy in pediatric RMS.

Pediatric rhabdomyosarcoma with bone marrow metastasis

BACKGROUND

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of adolescence and childhood. Although most patients with localized RMS are cured, outcome of those with metastatic disease remains unsatisfactory. RMS with bone marrow (BM) metastasis accounts for approximately 6% of all cases with RMS and has a 3-year event-free survival of 14%. Our study aims to describe our institution's experience of patients with metastatic RMS with BM involvement.

METHODS

This was a single-institution retrospective study from Memorial Sloan Kettering Kids, a tertiary pediatric oncology center. Patients with RMS who were diagnosed with BM metastasis between 1998 and 2018 were identified from pathology reports.

RESULTS

For patients with RMS and BM positivity at diagnosis (N = 27), the median survival was 1.5 years. The 1-, 2-, and 3-year overall survival (OS) were 81%, 32%, and 20%, respectively. There is one long-term (defined as >4 year) survivor who is still alive 14.9 years after diagnosis despite two metastatic recurrences. An Oberlin status of 4 that included BM metastasis portended a 3-year OS of 0%.

CONCLUSIONS

Although most patients will respond to initial therapy, BM metastasis at the time of diagnosis lends a near-fatal diagnosis in pediatric patients with RMS. Novel therapies are desperately needed to consolidate their initial remission.

The impact of 18F-FDG PET on initial staging and therapy planning of pediatric soft-tissue sarcoma patients

BACKGROUND

Soft-tissue sarcomas in children are a histologically heterogenous group of malignant tumors accounting for approximately 7% of childhood cancers. There is a paucity of data on the value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) for initial staging and whether PET influenced management of these patients.

OBJECTIVE

The aim of this analysis is to assess the use of ¹⁸F-FDG PET exclusively, and as a supplement to cross-sectional imaging in comparison to typical imaging protocols (CT and magnetic resonance imaging [MRI]) for initial staging as well as therapy planning in pediatric soft-tissue sarcoma patients.

MATERIALS AND METHODS

The list of ¹⁸F-FDG PET/CT performed for soft-tissue sarcoma between March 2007 and October 2017 was obtained from the Hospital Information System database. Twenty-six patients who had received ¹⁸F-FDG PET, MRI and/or CT at initial diagnosis were included in the study. ¹⁸F-FDG PET and concurrent diagnostic CT and MRI at initial staging were independently reviewed to note the number of primary and metastatic lesions detected by each modality. A chart review was conducted to collect information on final diagnosis, staging and treatment plan.

RESULTS

During the study period, 26 patients (15 females) ages 1.3-17.9 years (median age: 6 years) had received ¹⁸F-FDG PET/CT at initial diagnosis of soft-tissue sarcoma. Diagnostic CT was available for comparison in all 26 patients and MRI was available in 18 patients. The mean interval between cross-sectional imaging and ¹⁸F-FDG PET was 5.9 days (range: 0-30 days). All 26 primary lesions were equally detected by ¹⁸F-FDG PET compared to CT and MRI. From 84 metastatic lesions, 16 were detected by PET as well as CT and MRI, 12 by ¹⁸F-FDG PET only (included mainly lymph node metastases) and 56 by CT and MRI only (included mainly lung metastases). ¹⁸F-FDG PET changed therapy planning in 5 patients out of 26 (19%) by showing additional lesions not detected by CT and MRI.

CONCLUSION

¹⁸F-FDG PET proved to be a valuable tool for precise initial staging of pediatric soft-tissue sarcoma patients, especially in detecting lymph node metastasis, and could be included in their initial work-up. Given the relative rarity and heterogeneity of this group of tumors, additional investigations are required to definitely establish a role for ¹⁸F-FDG PET in the initial staging and therapy planning of soft-tissue sarcoma in the pediatric population.

Applications of PET-MRI in musculoskeletal disease

New integrated PET-MRI systems potentially provide a complete imaging modality for diagnosis and evaluation of musculoskeletal disease. MRI is able to provide excellent high-resolution morphologic information with multiple contrast mechanisms that has made it the imaging modality of choice in evaluation of many musculoskeletal disorders. PET offers incomparable abilities to provide quantitative information about molecular and physiologic changes that often precede structural and biochemical changes. In combination, hybrid PET-MRI can enhance imaging of musculoskeletal disorders through early detection of disease as well as improved diagnostic sensitivity and specificity. The purpose of this article is to review emerging applications of PET-MRI in musculoskeletal disease. Both clinical applications of malignant musculoskeletal disease as well as new opportunities to incorporate the molecular capabilities of nuclear imaging into studies of nononcologic musculoskeletal disease are discussed. Lastly, we discuss some of the technical considerations and challenges of PET-MRI as they specifically relate to musculoskeletal disease.

LEVEL OF EVIDENCE

5 TECHNICAL EFFICACY: Stage 3 J. Magn. Reson. Imaging 2018;48:27-47.

PET in the Diagnostic Management of Soft Tissue Sarcomas of Musculoskeletal Origin

Soft tissue sarcomas (STSs) account for less than 1% of adult solid tumors and about 7% of pediatric malignancies, causing 2% of cancer-related deaths. With the advent of PET-computed tomography (CT), the value of (18) fluorine-2-fluoro-2-deoxy-d-glucose (FDG) PET imaging to improve the management of STSs has been explored. FDG PET imaging has been found useful in restaging and treatment response assessment. This article reviews current knowledge and application of FDG PET-CT in initial diagnosis, staging, restaging, treatment response monitoring, and prognosis, with a brief overview of the most common histologic subtypes of STS.

Importance of whole-body imaging with complete coverage of hands and feet in alveolar rhabdomyosarcoma staging

BACKGROUND

Alveolar rhabdomyosarcoma commonly arises in the extremities and is characterized by aggressive biology and high frequency of metastases. Whole-body imaging is increasingly employed in pediatric oncology but not recommended as standard in the staging of soft-tissue sarcomas.

OBJECTIVE

After observing patients with a large symptomatic alveolar rhabdomyosarcoma lesion and a smaller silent lesion in the more distal part of an extremity we sought to estimate the frequency of this constellation.

MATERIALS AND METHODS

We retrospectively evaluated the data of prospectively registered paediatric patients (age <21 years) with alveolar rhabdomyosarcoma in the SoTiSaR (Soft Tissue Sarcoma Registry) of the Cooperative Weichteilsarkom Studiengruppe (CWS) 09/2011-04/2015 with regard to whole-body imaging.

RESULTS

Seventy-five patients were eligible. Images of 57 patients had been submitted for reference consultation, including 80 whole-body examinations in 36 patients. Among them were 5 patients (14%, 95% confidence interval 3-25%) who had been diagnosed because of a symptomatic lesion while an additional silent lesion in the distal part of an extremity had remained unnoticed and had only been detected by later whole-body imaging. It is noteworthy that in 42 (53%) of all 80 whole-body examinations, the hands and feet had been only partially covered or completely excluded.

CONCLUSION

In alveolar rhabdomyosarcoma silent lesions can be overlooked when the distal parts of the limbs are not thoroughly examined and not completely covered by imaging. Missing them influences treatment decisions and prognosis. Our results should be considered when evaluating the potential role of whole-body imaging in rhabdomyosarcoma.

Precision Medicine and PET-Computed Tomography in Pediatric Malignancies

Fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) PET-computed tomography (CT) plays a significant role in diagnosis, staging, therapy selection, and therapy assessment of multiple pediatric malignancies and facilitating precision medicine delivery in pediatric patients. In patients with Hodgkin lymphoma, interim fludeoxyglucose ¹⁸F-FDG PET/CT is highly sensitive and specific for predicting survival and multiple trials with FDG PET/CT-based adaptive therapies are currently ongoing. It is superior to iodine-131 metaiodobenzylguanidine (¹³¹I-MIBG) scintigraphy and bone scintigraphy for detecting metastases in neuroblastoma patients and sarcoma patients. It may predict histologic differentiation and neoadjuvant therapy assessment in Wilms tumor.

Paediatric nuclear medicine imaging

BACKGROUND

Nuclear medicine imaging explores tissue viability and function by using radiotracers that are taken up at cellular level with different mechanism. This imaging technique can also be used to assess blood flow and transit through tubular organs. Nuclear medicine imaging has been used in paediatrics for decades and this field is continuously evolving.

SOURCES OF DATA

The data presented comes from clinical experience and some milestone papers on the subject.

AREAS OF AGREEMENT

Nuclear medicine imaging is well-established in paediatric nephro-urology in the context of urinary tract infection, ante-natally diagnosed hydronephrosis and other congenital renal anomalies. Also, in paediatric oncology, I-123-meta-iodobenzyl-guanidine has a key role in the management of children with neuroblastic tumours. Bone scintigraphy is still highly valuable to localize the source of symptoms in children and adolescents with bone pain when other imaging techniques have failed. Thyroid scintigraphy in neonates with congenital hypothyroidism is the most accurate imaging technique to confirm the presence of ectopic functioning thyroid tissue.

AREAS OF CONTROVERSY

Radionuclide transit studies of the gastro-intestinal tract are potentially useful in suspected gastroparesis or small bowel or colonic dysmotility. However, until now a standardized protocol and a validated normal range have not been agreed, and more work is necessary. Research is ongoing on whether magnetic resonance imaging (MRI), with its great advantage of great anatomical detail and no ionizing radiations, can replace nuclear medicine imaging in some clinical context. On the other hand, access to MRI is often difficult in many district general hospitals and general anaesthesia is frequently required, thus adding to the complexity of the examination.

GROWING POINTS

Patients with bone pain and no cause for it demonstrated on MRI can benefit from bone scintigraphy with single photon emission tomography and low-dose computed tomography. This technique can identify areas of mechanical stress at cortical bone level, difficult to demonstrate on MRI, which can act as pain generators. Positron emission tomography (PET) is being tested in the staging, response assessment and at the end of treatment of several paediatric malignancies. PET is becoming more widely utilized in neurology in the pre-surgical assessment of some children with drug resistant epilepsy.

AREAS TIMELY FOR DEVELOPING RESEARCH

The use of PET/MRI scanners is very attractive as it combines benefits of MR imaging with the assessment of cellular viability and metabolism with PET in one examination. This imaging technique will allow important research on tumour in-vivo metabolism (possible applications include lymphomas, neuroblastomas, malignant germ cell tumours andbrain tumours), with the aim of offering a personalized biological profile of the tumour in a particular patient. Ground-breaking research is also envisaged in neurosciences, especially in epilepsy, using PET tracers that would enable a better identification of the epileptogenic focus, and in psychiatry, with the use of radiolabeled neurotransmitters. In paediatric nephro-urology, the identification of the asymptomatic child with ante-natally diagnosed hydronephrosis at risk of losing renal parenchymal function if left untreated is another area of active research involving radionuclide renography.

Nuclear Medicine in Pediatric and Adolescent Tumors

Nuclear medicine has an important role in the management of many cancers in pediatric age group with multiple imaging modalities and radiopharmaceuticals targeting various biological uptake mechanisms. 18-Flourodeoxyglucose is the radiotracer of choice especially in patients with sarcoma and lymphoma. (18)FDG-PET, for sarcoma and lymphomas, is proved to be superior to conventional imaging in staging and therapy response. Although studies are limited in pediatric population, (18)FDG-PET/CT has found its way through international guidelines. Limitations and strengths of PET imaging must be noticed before adapting PET imaging in clinical protocols. Established new response criteria using multiple parameters derived from (18)FDG-PET would increase the accuracy and repeatability of response evaluation. Current data suggest that I-123 metaiodobenzylguanidine (MIBG) remains the tracer of choice in the evaluation of neuroblastoma (NB) because of its high sensitivity, specificity, diagnostic accuracy, and prognostic value. It is valuable in determining the response to therapy, surveillance for disease recurrence, and in selecting patients for I-131 therapy. SPECT/CT improves the diagnostic accuracy and the interpretation confidence of MIBG scans. (18)FDG-PET/CT is an important complementary to MIBG imaging despite its lack of specificity to NB. It is valuable in cases of negative or inconclusive MIBG scans and when MIBG findings underestimate the disease status as determined from clinical and radiological findings. F-18 DOPA is promising tracer that reflects catecholamine metabolism and is both sensitive and specific. F-18 DOPA scintigraphy provides the advantages of PET/CT imaging with early and short imaging times, high spatial resolution, inherent morphologic correlation with CT, and quantitation. Regulatory and production issues currently limit the tracer's availability. PET/CT with Ga-68 DOTA appears to be useful in NB imaging and may have a unique role in selecting patients for peptide receptor radionuclide therapy with somatostatin analogues. C-11 hydroxyephedrine PET/CT is a specific PET tracer for NB, but the C-11 label that requires an on-site cyclotron production and the high physiologic uptake in the liver and kidneys limit its use. I-124 MIBG is useful for I-131 MIBG pretherapeutic dosimetry planning. Its use for diagnostic imaging as well as the use of F-18 labeled MIBG analogues is currently experimental. PET/MR imaging is emerging and is likely to become an important tool in the evaluation. It provides metabolic and superior morphological data in one imaging session, expediting the diagnosis and lowering the radiation exposure. Radioactive iodines not only detect residual tissue and metastatic disease but also are used in the treatment of differentiated thyroid cancer. However, these are not well documented in pediatric age group like adult patients. Use of radioactivity in pediatric population is very important and strictly controlled because of the possibility of secondary malignities; therefore, management of oncological cases requires detailed literature knowledge. This article aims to review the literature on the use of radionuclide imaging and therapy in pediatric population with thyroid cancer, sarcomas, lymphoma, and NB.

Stage 1 embryonal rhabdomyosarcoma of the female genital tract: a retrospective clinical study of nine cases

Background

The aim of the study is to investigate the clinical features, treatments, and prognosis of stage 1 embryonal rhabdomyosarcoma of the female genital tract.

Methods

A retrospective analysis was performed on nine cases of stage 1 embryonal rhabdomyosarcoma of the female genital tract. Clinical characteristics, treatments, recurrence, and prognosis were analyzed.

Results

Of the nine patients with embryonal rhabdomyosarcoma, three originated from the vagina and six from the cervix. For the eight patients who initially received surgery, the median survival time was 88 months. As for the six patients that received adjuvant chemotherapy, five of them who received six or more cycles of treatment achieved tumor-free survival and the survival time ranged from 9 to 228 months. The remaining patient, who declined further treatment after two cycles of chemotherapy, relapsed 11 months following the surgery and died 3 months later. Out of the nine patients, only one was initially treated with chemotherapy, and achieved complete remission, but relapsed 21 months later. After a combination of surgery and chemotherapy, this patient remained tumor-free for total of 117 months.

Conclusions

Patients with early stage embryonal rhabdomyosarcoma of the female genital tract have good prognosis, and the combination of surgery and chemotherapy can lead to better outcomes.

Rhabdomyosarcoma

A malignant tumor of striated muscle origin, rhabdomyosarcoma (RMS) is a childhood tumor that has benefited from nearly 30 years of multimodality therapy, culminating in a >70% overall 5-year survival. Prognosis for RMS is dependent on primary tumor site, age, completeness of resection, presence and number of metastatic sites, histology, and biology of the tumor cells. Multimodality treatment is based on risk stratification according to pre-treatment stage, postoperative group, histology, and site. Unique to RMS is the concept of postoperative clinical grouping that assesses the completeness of disease resection and takes into account lymph node evaluation at both the regional and metastatic basins. At all sites, if complete operative resection of disease is accomplished, including microscopic disease, survival is improved. Therefore, the surgeon plays a vital role in determining risk stratification for treatment, local control of the primary tumor and overall outcome for the patient with RMS.

Detection of lymph node metastases in pediatric and adolescent/young adult sarcoma: Sentinel lymph node biopsy versus fludeoxyglucose positron emission tomography imaging-A prospective trial

BACKGROUND

Lymph node metastases are an important cause of treatment failure for pediatric and adolescent/young adult (AYA) sarcoma patients. Nodal sampling is recommended for certain sarcoma subtypes that have a predilection for lymphatic spread. Sentinel lymph node biopsy (SLNB) may improve the diagnostic yield of nodal sampling, particularly when single-photon emission computed tomography/computed tomography (SPECT-CT) is used to facilitate anatomic localization. Functional imaging with positron emission tomography/computed tomography (PET-CT) is increasingly used for sarcoma staging and is a less invasive alternative to SLNB. To assess the utility of these 2 staging methods, this study prospectively compared SLNB plus SPECT-CT with PET-CT for the identification of nodal metastases in pediatric and AYA patients.

METHODS

Twenty-eight pediatric and AYA sarcoma patients underwent SLNB with SPECT-CT. The histological findings of the excised lymph nodes were then correlated with preoperative PET-CT imaging.

RESULTS

A median of 2.4 sentinel nodes were sampled per patient. No wound infections or chronic lymphedema occurred. SLNB identified tumors in 7 of the 28 patients (25%), including 3 patients who had normal PET-CT imaging of the nodal basin. In contrast, PET-CT demonstrated hypermetabolic regional nodes in 14 patients, and this resulted in a positive predictive value of only 29%. The sensitivity and specificity of PET-CT for detecting histologically confirmed nodal metastases were only 57% and 52%, respectively.

CONCLUSIONS

SLNB can safely guide the rational selection of nodes for biopsy in pediatric and AYA sarcoma patients and can identify therapy-changing nodal disease not appreciated with PET-CT. Cancer 2017;155-160. © 2016 American Cancer Society.

Rhabdomyosarcoma in adults: new perspectives on therapy

OPINION STATEMENT

Rhabdomyosarcoma (RMS) is well known as a pediatric disease. Most of the knowledge, like biology, genetics, and treatments of this disease, comes from studies done in that age group. The two subtypes of RMS, embryonic RMS and alveolar RMS, that affect mainly the pediatric population are well described in the literature and that has had an impact on the improvement in overall survival during the past 20 years. RMS in the adult population has a low incidence, therefor the study of RMS in this group is challenging. Pleomorphic RMS is the subtype that mainly affects adults and its biology and genetics are not yet completely understood and described. The risk factors for this tumor and the differences among adults and children is also poorly understood. The treatments for adults that have RMS are not standardized having an impact on the overall survival. Pleomorphic RMS has, compared to other adult sarcomas, poor overall survival. Adult patients with RMS have poor prognosis. The standardization of treatments for the adult population is necessary as maybe new treatments for this specific group. There are new treatment options that are being studied mostly in pediatrics and young adults. Immunotherapy is currently proposed as an important treatment possibility including different techniques like vaccination, antigen-mediated therapy, and immune checkpoints. Even if we have a better understanding of RMS, there are still unanswered questions. The improvements seen in the pediatric population are encouraging, but there is still the need to enhance better therapies for adults with RMS.

Orbital tumours and tumour-like lesions: exploring the armamentarium of multiparametric imaging

Although the orbit is a small anatomical space, the wide range of structures present within it are often the site of origin of various tumours and tumour-like conditions, both in adults and children. Cross-sectional imaging is mandatory for the detection, characterization, and mapping of these lesions. This review focuses on multiparametric imaging of orbital tumours. Each tumour is reviewed in relation to its clinical presentation, compartmental location, imaging characteristics, and its histological features. We herein describe orbital tumours as lesions of the globe (retinoblastoma, uveal melanoma), optic nerve sheath complex (meningioma, optic nerve glioma), conal-intraconal compartment (hemangioma), extraconal compartment (dermoid/epidermoid, lacrimal gland tumours, lymphoma, rhabdomysarcoma), and bone and sinus compartment (fibrous dysplasia). Lesions without any typical compartmental localization and those with multi-compartment involvement (veno-lymphatic malformation, plexiform neurofibroma, idiopathic orbital pseudotumour, IgG4 related disease, metastases) are also reviewed. We discuss the role of advanced imaging techniques, such as MR diffusion-weighted imaging (DWI), diffusion tensor imaging, fluoro-2-deoxy-D-glucose positron emission tomography CT (FDG-PET CT), and positron emission tomography MRI (MRI PET) as problem-solving tools in the evaluation of those orbital masses that present with non-specific morphologic imaging findings. Main messages/Teaching points • A compartment-based approach is essential for the diagnosis of orbital tumours. • CT and MRI play a key role in the work-up of orbital tumours. • DWI, PET CT, and MRI PET are complementary tools to solve diagnostic dilemmas. • Awareness of salient imaging pearls and diagnostic pitfalls avoids interpretation errors.

Combined positron emission tomography/computed tomography (PET/CT) for imaging of orbital tumours and tumours extending into the orbit

OBJECTIVE

To assess clinical and radiological performance of combined positron emission tomography/computed tomography (PET/CT) in patients with secondary and primary intraorbital tumours.

METHODS

14 adults with secondary and 1 child with primary orbital masses underwent combined whole-body PET/CT. Radiopharmaceutical tracers applied were (18F)-fluorodeoxyglucose, (18F)-fluoroethylcholine (FEC) and (68Ga)-DOTATATE. Histopathology and/or all conventional radiographic work-up and clinical course served as standard of reference. Descriptive statistics and Fisher's exact test were used for analysis.

RESULTS

PET/CT detected all orbital masses. All 15 patients had malignant disease. Local osseous infiltration was correctly identified in 11 patients. Lymph node metastases were present in two of eight patients (25%) with haematogenous orbital metastases and in five of six patients (83%) with infiltrative carcinoma (p=0.05). Further distant metastases were present in all eight patients suffering from orbital metastases, but only one patient with infiltrative carcinoma (17%) presented with disseminated disease (p=0.003). In one metastasis, PET/CT excluded vital orbital tumour tissue after radiation therapy. Local recurrence was detected in another patient suffering from prostate cancer.

CONCLUSION

PET/CT is a sensitive tool for the detection and localisation of orbital masses, enabling assessment of both morphology and cell metabolism. Detailed imaging of the head and neck region with a small field-of-view should be performed when suspecting lymphatic metastases. As metastatic disease to the orbit is associated with advanced disease, focus should be laid on whole-body imaging for staging of these patients. Different radiopharmaceutical tracers can be applied to distinguish the origin of orbital metastases.

Alveolar rhabdomyosarcoma confined to the bone marrow with no identifiable primary tumour using FDG-PET/CT

Background

Rhabdomyosarcoma (RMS), a malignant tumour of mesenchymal origin which can occur at various sites in the body, is one of the most common soft tissue sarcomas in both children and adolescents, but is rare in adults with a prevalence of less than 1 %. The alveolar subtype of rhabdomyosarcoma (ARMS) is typically characterized by a specific reciprocal chromosomal translocation involving the PAX3 and FKHR or PAX7 and FKHR genes, respectively. ARMS is most frequently seen in childhood, and typically affects the sinuses and soft tissue of the extremities, with approximately 23 % exhibiting metastasis to the marrow. Non-invasive F-18-fluorodeoxyglucose positron-emission tomography (FDG-PET) scans have a high ability to detect lymph nodes, bone, and bone marrow involvement in patients with metastatic RMS, often with higher sensitivity and specificity compared with conventional modalities.

Case presentation

Here, we report an unusual case of ARMS confined to the bone marrow in an older adult that lacked an identifiable primary tumour using FDG-PET/CT and mimicked a haematological disease with pancytopenia but without abnormal findings by FDG-PET/CT. The patient was initially treated with topotecan/cyclophosphamide and subsequently switched to vinorelbine. Due to severe toxicity the treatment was discontinued, however after 7-months follow-up, the patient is still alive with an improved general state of health and only a mild pancytopenia with no need for blood transfusions.

Conclusion

Rhabdomyosarcoma can be limited to the bone marrow with no identifiable primary tumour. This case shows that the use of a bone marrow biopsy in suspected malignancies affecting the bone marrow is irreplaceable.

Current management of paratesticular rhabdomyosarcoma

OBJECTIVES

Paratesticular rhabdomyosarcoma accounts for 7-10% of genitourinary rhabdomyosarcoma tumors and is the 3rd most common after RMS of the prostate and bladder. Though most (60%-80%) patients with paratesticular rhabdomysarcoma present with localized disease, assessment of systemic disease is vital. The treatment of paratesticular rhabdomyosarcoma has evolved over several decades; the current standard of care is multimodal treatment including surgery, chemotherapy, and radiation. We give insight into the evolution of treatment, present the oncologic outcomes of seminal studies, and summarize the current recommendations for the management of these patients.

METHODS

A comprehensive search of the literature on the electronic databases PubMed was conducted for management of paratesticular rhabdomyosarcoma. Case reports were excluded, clinical trials from all the oncologic society were reviewed and relevant articles are included in the review.

RESULTS

The treatment regimen is based on following principles: (1) local control of the primary site with radical orchiectomy and (2) assessment of local control and distant sites. Further treatment is directed according to disease stage, histology, and age of the patient. The goal of treatment is to achieve cure or maximum tumor control while minimizing toxicity.

CONCLUSIONS

With the changing landscape in the management of paratesticular rhabomyosarcoma, significant improvement is evident in the oncologic outcomes. Further advance in genomic testing would lead us to tailor treatment based on individual risk factors and minimize long-term side effects.

[Embryonal paratesticular rhabdomyosarcoma: a case report and a literature review]

Paratesticular rhabdomyosarcoma is a rare tumor. Multimodality treatment should involve surgery, radiotherapy and chemotherapy, which are indicated according to risk groups. Risk group stratification depends on pretreatment staging and definitive histology. Patients older than 10years or those with suspected lymph nodes on imaging have higher incidence of lymph node involvement. Prognosis is excellent for localized tumors, survival rates exceed 90%. We report a case of embryonal paratesticular rhabdomyosarcoma treated in our institution.

Value of FDG PET/CT in Patient Management and Outcome of Skeletal and Soft Tissue Sarcomas

Fluorodeoxyglucose (FDG)-PET/computed tomography (CT) has been increasingly used in bone and soft tissue sarcomas and provides advantages in the initial tumor staging, tumor grading, therapy assessment, and recurrence detection. FDG-PET/CT metabolic parameters are reliable predictors of survival in sarcomas and could be implemented in risk stratification models along with other prognostic factors in these patients.

An emerging evidence base for PET-CT in the management of childhood rhabdomyosarcoma: systematic review

INTRODUCTION

Rhabdomyosarcoma (RMS) management depends on risk stratification at diagnosis and treatment response. Assessment methods include CT, MRI, bone scintigraphy, histological analysis and bone marrow biopsy. Advanced functional imaging (FI) has potential to improve staging accuracy and management strategies.

METHODS AND ANALYSIS

We conducted a systematic review (PROSPERO 2013:CRD42013006128) of diagnostic accuracy and clinical effectiveness of FI in histologically proven paediatric RMS. PRISMA guidance was followed. We searched 10 databases to November 2013. Studies with ≥10 patients with RMS which compared positron emission tomography (PET), PET-CT or diffusion-weighted imaging (DWI) MRI to conventional imaging at any treatment stage were included. Study quality was assessed. Limited, heterogeneous effectiveness data required narrative synthesis, illustrated by plotting sensitivity and specificity in receiver operating curve (ROC) space.

RESULTS

Eight studies (six PET-CT, two PET) with 272 RMS patients in total were included. No DWI-MRI studies met inclusion criteria. Pooled estimates were not calculated due to sparseness of data. Limited evidence indicated initial PET-CT results were predictive of survival. PET-CT changed management of 7/40 patients. Nodal involvement PET-CT: sensitivity ranged from 80% to 100%; specificity from 89% to 100%. Distant metastatic involvement: PET-CT sensitivity ranged from 95% to 100%; specificity from 80% to100%. Data on metastases in different sites were sparse. Limited data were found on outcome prediction by PET-CT response.

DISSEMINATION AND ETHICS

PET/PET-CT may increase initial staging accuracy in paediatric RMS, specifically in the detection of nodal involvement and distant metastatic spread. There is a need to further assess PET-CT for this population, ideally in a representative, unbiased and transparently selected cohort of patients.

Hybrid Imaging in Oncology

In oncology various imaging modalities play a crucial role in diagnosis, staging, restaging, treatment monitoring and follow up of various cancers. Stand-alone morphological imaging like computerized tomography (CT) and magnetic resonance imaging (MRI) provide a high magnitude of anatomical details about the tumor but are relatively dumb about tumor physiology. Stand-alone functional imaging like positron emission tomography (PET) and single photon emission tomography (SPECT) are rich in functional information but provide little insight into tumor morphology. Introduction of first hybrid modality PET/CT is the one of the most successful stories of current century which has revolutionized patient care in oncology due to its high diagnostic accuracy. Spurred on by this success, more hybrid imaging modalities like SPECT/CT and PET/MR were introduced. It is the time to explore the potential applications of the existing hybrid modalities, developing and implementing standardized imaging protocols and train users in nuclear medicine and radiology. In this review we discuss three existing hybrid modalities with emphasis on their technical aspects and clinical applications in oncology.