Urogenital tumours in childhood

Bilateral Nephroblastomatosis With a Unilateral Wilms Tumor: A Case Report Highlighting Imaging Characteristics

Nephrogenic rests (NRs) are foci of embryonic nephrogenic cells that persist beyond the 36th week of gestation. They are precursor lesions of Wilms tumor and are found incidentally in approximately 1% of infants. The term nephroblastomatosis (NBS) is utilized when nephrogenic rests extensively or multifocally affect the kidneys. We report a case of a left nephroblastoma with bilateral nephroblastomatosis, treated with neoadjuvant chemotherapy followed by a left nephrectomy, highlighting the imaging features of nephrogenic rests on ultrasound, CT, and MRI, and the potential possibilities of distinguishing nephroblastomas from nephrogenic rests in one hand, and the possibilities of distinguishing active nephrogenic rests from inactive ones in the other hand. We furthermore discuss the role of histology in making those distinctions, and the role of chemotherapy in reducing nephrogenic rests' size and cellularity.

Diagnostic journey and multimodal management of a rare urogenital rhabdomyosarcoma with rectovaginal fistula in an adolescent: a case report

Introduction and importance

Rhabdomyosarcoma is a malignant tumour that originates from immature muscle cells and belongs to the category of soft-tissue sarcomas. It is predominantly diagnosed in children under the age of 6. This condition can manifest within the genitourinary tract and may exhibit non-specific symptoms such as changes in bowel habits and fever. Early detection and a comprehensive, multidisciplinary approach are essential to achieving more favourable outcomes. This report highlights an uncommon case of urogenital rhabdomyosarcoma in a 15-year-old girl, in addition to the presence of a rectovaginal fistula.

Case presentation

A 15-year-old girl with presented with fever, altered bowel habits, and a lump in her lower abdomen, abdominal discomfort, and incomplete bowel evacuation. She also had faecal discharge from the vagina. Diagnostic imaging and biopsy confirmed urogenital rhabdomyosarcoma with a rectovaginal fistula. The patient is currently undergoing induction chemotherapy and is scheduled for radiation therapy and surgery.

Clinical discussion

Rhabdomyosarcoma is a rare paediatric oncologic concern due to its aggressive nature and potential metastasis. The presentation varies based on age, tumour location, and metastasis presence. This patient presented with altered bowel habits, a pelvic mass and unusual feculent discharge, suggesting a rectovaginal fistula. Diagnostic imaging confirmed the diagnosis, and induction chemotherapy led to a positive response and reduced tumour size.

Conclusion

Urogenital rhabdomyosarcoma is an aggressive malignancy with non-specific symptoms, making early diagnosis challenging. An accurate diagnosis requires high suspicion, imaging, and a biopsy. Multidisciplinary management, including surgery, chemotherapy, and radiation therapy, improves outcomes and improves paediatric patients' prognosis and quality of life.

MRI Characteristics of Pediatric and Young-Adult Renal Cell Carcinoma: A Single-Center Retrospective Study and Literature Review

Pediatric renal cell carcinoma (RCC) is a rare malignancy. Magnetic resonance imaging (MRI) is the preferred imaging modality for assessment of these tumors. The previous literature has suggested that cross-sectional-imaging findings differ between RCC and other pediatric renal tumors and between RCC subtypes. However, studies focusing on MRI characteristics are limited. Therefore, this study aims to identify MRI characteristics of pediatric and young-adult RCC, through a single-center case series and literature review. Six identified diagnostic MRI scans were retrospectively assessed, and an extensive literature review was conducted. The included patients had a median age of 12 years (63-193 months). Among other subtypes, 2/6 (33%) were translocation-type RCC (MiT-RCC) and 2/6 (33%) were clear-cell RCC. Median tumor volume was 393 cm³ (29-2191 cm³). Five tumors had a hypo-intense appearance on T2-weighted imaging, whereas 4/6 were iso-intense on T1-weighted imaging. Four/six tumors showed well-defined margins. The median apparent diffusion coefficient (ADC) values ranged from 0.70 to 1.20 × 10^-3 mm²/s. In thirteen identified articles focusing on MRI characteristics of MiT-RCC, the majority of the patients also showed T2-weighted hypo-intensity. T1-weighted hyper-intensity, irregular growth pattern and limited diffusion-restriction were also often described. Discrimination of RCC subtypes and differentiation from other pediatric renal tumors based on MRI remains difficult. Nevertheless, T2-weighted hypo-intensity of the tumor seems a potential distinctive characteristic.

Embryonal Rhabdomyosarcoma of Prostate in Adult: A Rare Case Report

Rhabdomyosarcoma is the fifth most common type of soft tissue solid tumor in children and the most common in the last two decades. Rhabdomyosarcoma of the urogenital organ is a rare mesenchymal tumor, covering 22% of all Rhabdomyosarcoma cases. The two most common histologic types are alveolar and embryonal, whereas botryoid and spindle cells are rarely found. We reported a case of embryonal Rhabdomyosarcoma of the prostate. In this study, we improved the understanding of Embryonal Rhabdomyosarcoma of the prostate on 23 years old male who had a history of swelling in the perineal area and a history of falling from a height in the groin area 5 months before. The patient complains of the difficulty of urinating and hematuria one month after falling. We underwent drainage of the swelling area, found pus 100cc and took a sample for pathological examination. The result was embryonal rhabdomyosarcoma. Prostate volume was 122cc, PSA 5,32 and PSAD 0,04. The CT scan result was solid mass size 15x8x18 cm at perineum enhance to the pelvic cavity, push the bladder to the superior, rectum to posterior, and urethra posterior to the left side. We diagnosed this patient as Embryonal Rhabdomyosarcoma prostate T2bG1N0M0 (stage 3) group 3 and intermediate-risk group. The patient underwent VAC chemotherapy based on D.9803 (IRS V) protocol and planned radiotherapy, but it stopped at halfway because of profuse bleeding. Embryonal Rhabdomyosarcoma is an aggressive tumor, especially in adults. However, there was limited evidence and guideline to diagnose and manage the disease.

CT-Based Radiomics to Differentiate Pelvic Rhabdomyosarcoma From Yolk Sac Tumors in Children

Background

The purpose of this study was to investigate the role of CT radiomics features combined with a support vector machine (SVM) model in potentially differentiating pelvic rhabdomyosarcoma (RMS) from yolk sac tumors (YSTs) in children.

Methods

A total of 94 patients with RMS (n = 49) and YSTs (n = 45) were enrolled. Non-enhanced phase (NP), arterial phase (AP), and venous phase (VP) images were retrieved for analysis. The volumes of interest (VOIs) were constructed by segmenting tumor regions on CT images to extract radiomics features. Datasets were randomly divided into two sets including a training set and a test set. In the training set, the least absolute shrinkage and selection operator (LASSO) algorithm was used to screen out the optimal radiomics features that could distinguish RMS from YSTs, and the features were combined with the SVM algorithm to build the classifier model. In the testing set, the areas under the receiver operating characteristic (ROC) curves (AUCs), accuracy, specificity, and sensitivity of the model were calculated to evaluate its diagnostic performance. The clinical factors (including age, sex, tumor site, tumor volume, AFP level) were collected.

Results

In total, 1,321 features were extracted from the NP, AP, and VP images. The LASSO regression algorithm was used to screen out 23, 26, and 17 related features, respectively. Subsequently, to prevent model overfitting, the 10 features with optimal correlation coefficients were retained. The SVM classifier achieved good diagnostic performance. The AUCs of the NP, AP, and VP radiomics models were 0.937 (95% CI: 0.862, 0.978), 0.973 (95% CI: 0.913, 0.996), and 0.855 (95% CI: 0.762, 0.922) in the training set, respectively, which were confirmed in the test set by AUCs of 0.700 (95% CI: 0.328, 0.940), 0.800 (95% CI: 0.422, 0.979), and 0.750 (95% CI: 0.373, 0.962), respectively. The difference in sex, tumor volume, and AFP level were statistically significant (P < 0.05).

Conclusions

The CT-based radiomics model can be used to effectively distinguish RMS and YST, and combined with clinical features, which can improve diagnostic accuracy and increase the confidence of radiologists in the diagnosis of pelvic solid tumors in children.

Satisfaction of Search: Recurrent Wilms Tumor Mimicking Chest Port Granuloma on Chest Film

Wilms tumor (nephroblastoma) is the most common renal malignancy of childhood and typically presents as a painless abdominal mass. The high success rates of surgery and chemotherapy make recurrence of Wilms tumor uncommon. We report the case of a 5-year-old girl who underwent radical nephrectomy and chemotherapy for a Wilms tumor, but suffered a relapse of the tumor to the lung. The metastasis was initially detected as a density on chest radiograph that was, coincidentally, in the same location as a recently explanted chest port. The diagnosis of recurrent malignancy was thus obscured by the patient’s history as well as a correlating physical examination finding of a palpable mass at the site of the previously placed chest port. Moreover, the mass was not seen on lateral view, all of which suggested an alternative diagnosis of granulation tissue versus seroma rather than recurrent Wilms tumor. A high degree of clinical suspicion was necessary on the part of the clinician and radiologist to diagnose the relapse.

The role of imaging in the initial investigation of paediatric renal tumours

Imaging has a key role in the assessment of paediatric renal tumours, especially when the initial treatment approach is to proceed to standard chemotherapy without histological confirmation. In Europe, according to the International Society of Paediatric Oncology guidelines, core needle biopsy is not routinely done unless the child is older than 10 years. Between age 6 months and 9 years, the child is treated with a standard regimen of preoperative chemotherapy unless there are concerns about non-Wilms' tumour pathology. Atypical imaging findings could therefore stratify a child into a different treatment protocol, and can prompt the need for pretreatment histology. This review details the latest protocols and techniques used in the assessment of paediatric renal tumours. Important imaging findings are discussed, especially the features that might prompt the need for a pretreatment biopsy. Local radiology practices vary, but both MRI and CT are widely used as routine imaging tests for the assessment of paediatric renal tumours in Europe. Advances in imaging technology and MRI sequences are facilitating the development of new techniques, which might increase the utility of imaging in terms of predicting tumour histology and clinical behaviour. Several of these new imaging techniques are outlined here.

What MRI can tell us about neurogenic tumors and rhabdomyosarcoma

This review focuses on the MRI features of neurogenic tumors and rhabdomyosarcoma in children. Neurogenic tumors include those arising from a nerve sheath and neuroblastic tumors that arise from the sympathetic nervous system. Nerve sheath tumors can be benign or malignant and occur sporadically or in association with neurofibromatosis type 1. Neuroblastic tumors comprise a spectrum of tumors ranging from highly malignant neuroblastoma to the benign ganglioneuroma. These neurogenic tumors arise in typical locations within the chest, abdomen and pelvis and have distinctive and characteristic imaging features that should suggest their diagnosis. Rhabdomyosarcoma encompasses a variety of histological subtypes that exhibit varying degrees of aggressiveness and biological behavior. While some abdominal and pelvic locations are well known to give rise to rhabdomyosarcoma, this tumor can arise in any tissue in the body except bone. The paper reviews the MRI and clinical features of neurogenic tumors and rhabdomyosarcoma and the imaging findings that can aid in clinical management.

2-deoxy-2-(18F)fluoro-D-glucose positron emission tomography/computed tomography imaging in paediatric oncology

Positron emission tomography (PET) is a minimally invasive technique which has been well validated for the diagnosis, staging, monitoring of response to therapy, and disease surveillance of adult oncology patients. Traditionally the value of PET and PET/computed tomography (CT) hybrid imaging has been less clearly defined for paediatric oncology. However recent evidence has emerged regarding the diagnostic utility of these modalities, and they are becoming increasingly important tools in the evaluation and monitoring of children with known or suspected malignant disease. Important indications for 2-deoxy-2-(¹⁸F)fluoro-D-glucose (FDG) PET in paediatric oncology include lymphoma, brain tumours, sarcoma, neuroblastoma, Langerhans cell histiocytosis, urogenital tumours and neurofibromatosis type I. This article aims to review current evidence for the use of FDG PET and PET/CT in these indications. Attention will also be given to technical and logistical issues, the description of common imaging pitfalls, and dosimetric concerns as they relate to paediatric oncology.

Paediatric benign cystic monodermal testicular teratoma

We present a case of a painless progressively increasing mass in the left upper testis in a 5-year-old boy, which was detected by his father performing testicular examination after observing asymmetry of the scrotum. Clinical examination, tumour markers, ultrasound scan including colour Doppler studies, and finally inguinal exploration and histopathology were helpful in establishing the diagnosis of benign cystic monodermal testicular teratoma. Testicular teratoma should be considered in the differential diagnosis of any child presenting with non-traumatic painless progressive scrotal swelling. Inguinal radical orchiectomy is the traditional gold standard treatment for benign testicular teratoma in children. Testis-sparing surgery should be reserved for smaller testicular tumours known to be benign.