MR imaging of scrotal tumors and pseudotumors

Diffusion tensor imaging and fiber tractography of the normal epididymis

PURPOSE

To evaluate the feasibility of diffusion tensor imaging (DTI) and fiber tractography (FT) of the normal epididymis and to determine normative apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values.

METHODS

Twenty-eight healthy volunteers underwent MRI of the scrotum, including DTI on a 3.0 T system. For each anatomic part of the epididymis (head, body and tail) free-hand regions of interest were drawn and the mean ADC and FA were measured by two radiologists in consensus. Parametric statistical tests were used to determine intersubject differences in ADC and FA between the anatomic parts of each normal epididymis and between bilateral epididymides. Fiber tracts of the epididymis were reconstructed using the MR Diffusion tool.

RESULTS

The mean ADC and FA of the normal epididymis was 1.31 × 10-3 mm2/s and 0.20, respectively. No differences in ADC (p = 0.736) and FA (p = 0.628) between the anatomic parts of each normal epididymis were found. Differences (p = 0.020) were observed in FA of the body between the right and the left epididymis. FT showed the fiber tracts of the normal epididymis. Main study's limitations include the following: small number of participants with narrow age range, absence of histologic confirmation and lack of quantitative assessment of the FT reconstructions.

CONCLUSION

DTI and FT of the normal epididymis is feasible and allow the noninvasive assessment of the structural and geometric organization of the organ.

Paratesticular fibrous pseudotumour: a rare cause of an intrascrotal mass

This report describes a boy in his early adolescence who was referred to a urologist with a large, painless right scrotal mass. Following a thorough workup, the patient underwent surgical removal of the mass, which was revealed to be a paratesticular fibrous pseudotumour (PFP) on histopathological analysis. This diagnosis is rare and can often prove difficult to distinguish from a malignant lesion within the scrotum. We have conducted a review of the current literature surrounding PFP to compliment the case discussion.

Multimodal ultrasound diagnosis of epididymo-orchitis with secondary testicular infarction: A case report

We report a case of a 48-year-old man with testicular infarction caused by epididymo-orchitis (EO). Multimodal ultrasound showed extensive necrosis of the testis, and the patient underwent right orchiectomy. Postoperative pathology confirmed extensive necrosis of the testis. After 3 months of follow-up, the examination of scrotal ultrasound showed that the left testis and epididymis had no obvious abnormality.

Extratesticular masses focusing on MRI findings

Scrotal masses, whether cystic or solid lesions, are routinely evaluated using ultrasonography. Magnetic resonance imaging (MRI) may be used for further investigation in cases with atypical findings, difficult diagnoses, large masses, and/or unclear relationships with the surrounding tissues. Scrotal solid masses are divided into intra- and extra-testicular masses. A staggering 90% of the intratesticular masses are malignant, whereas 75% of extratesticular masses are benign. Extratesticular masses are less common than intratesticular masses; however, some extratesticular masses present characteristic MRI findings. Familiarity with these specific MRI features of extratesticular masses is beneficial to radiologists, as appropriate diagnoses can help avoid unnecessary invasive treatments such as orchiectomy. In this review, we describe fibrous pseudotumors, polyorchidism, adenomatoid tumors, and scrotal leiomyoma as benign paratesticular masses, focusing on their characteristic imaging features on MRI. Although these tumors are extremely rare, their MRI findings are distinctive, and accurate diagnoses can prevent unnecessary orchiectomy. In addition, to demonstrate the pitfalls of diagnosing extratesticular masses, we present a case of seminoma misidentified as extratesticular masses due to large extensions outside the testis. Spermatic cord sarcoma, including rhabdomyosarcoma, leiomyosarcoma, and liposarcoma, and metastasis to the spermatic cord are described as malignant extratesticular masses. This review focused on extratesticular masses and elaborates the imaging findings that can aid in the accurate diagnosis using MRI.

Soft-Tissue Sarcomas of the Genitourinary Tract with Radiologic-Pathologic Correlation

Genitourinary tract soft-tissue sarcomas are rare neoplasms with varied pathologic and clinical features. While some of these tumors may be aggressive high-grade malignancies, others are low grade with a relatively better prognosis. Given that the grade and extent of the disease are important prognostic factors in these tumors, timely diagnosis is crucial. Unfortunately, most imaging features of these malignancies are not pathognomonic, and various histologic subtypes do not manifest with typical classic imaging features. Therefore, reliable differentiation of the various histologic tumor types is not always possible based solely on the radiologic manifestations. Imaging findings need to be considered in the context of clinical history in corroboration with radiologic-pathologic correlation. The authors discuss the specific imaging and pathologic characteristics of various genitourinary tract soft-tissue sarcomas, emphasizing diagnostic difficulties and differential diagnoses. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Paratesticular Ewing's sarcoma

This case report follows a 23-year-old man who presented with a painful right scrotal mass which was found to be a paratesticular vascular solid mass on ultrasound, and after uncomplicated orchiectomy, was revealed to be a high-grade extraskeletal Ewing's sarcoma. Diagnosis leading up to the orchiectomy was primarily clinical with only ultrasound used in identification and characterization of the paratesticular mass. Paratesticular masses are more commonly benign, and ultrasound is the first modality, with computed tomography and magnetic resonance imaging providing more definitive findings. We discuss imaging findings and histopathology of this rare tumor with an uncommon presentation.

Visualizing the early-stage testicular torsion by dual-modal photoacoustic and ultrasound imaging

Delayed treatment of testicular torsion (TT) can lead to permanent loss of reproductive capacity. Photoacoustic imaging (PAI) and ultrasound imaging (USI) was tested for detecting TT at early stage in mice based on PAI-obtained oxygen saturation (sO₂), and USI-collected color pixel density (CPD), peak systolic velocity (PSV) and resistance index (RI). For complete TT, both CPD (9.08 % ± 3.084 to almost zero) and sO₂ data (70.09 % ± 1.656-59.84 % ± 1.427) showed an significant change 2 h post-torsion. For incomplete TT, sO₂ data exhibited a strong time relationship (Mean values: 6 h, 64.83 % ± 1.898; 12 h, 60.67 % ± 3.555; 24 h, 57.85 % ± 3.575; P < 0.05). However, USI-collected CPD, PSV or IR data from the same TT models showed no significant difference. This study indicated that USI and PAI could identify complete TT. Meanwhile, PAI has shown great potential in the diagnosis of incomplete TT within 24 h based on time-related sO₂ map.

Imaging of pediatric testicular tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper

Primary intratesticular tumors are uncommon in children, but incidence and risk of malignancy both sharply increase during adolescence. Ultrasound is the mainstay for imaging the primary lesion, and cross-sectional modalities are often required for evaluation of regional or distant disease. However, variations to this approach are dictated by additional clinical and imaging nuances. This paper offers consensus recommendations for imaging of pediatric patients with a known or suspected primary testicular malignancy at diagnosis and during follow-up.

Benign Paratesticular Fibrous Pseudotumor in a Young Male: A Case Report

Paratesticular fibrous pseudotumor (PFPs) is an uncommon intra-scrotal mass that originated from tunica vaginalis and resulted in a reactive fibrous proliferation after a history of inflammation, infection, trauma, or hydrocele. We report here on a case of a 17-year-old man with a mass in the hemiscrotum that was found to be PFP in the orchidectomy specimen pathologic examination. The diagnosis of PFPs, before and during the operation, can be complicated despite it being a benign tumor. Radical orchidectomy is usually performed for these types of lesions. A frozen section intraoperatively is essential to avoid unnecessary radical orchidectomy and preserve testicle.

Gamut of Extratesticular Scrotal Masses: Anatomic Approach to Sonographic Differential Diagnosis

The commonly taught tenet that intratesticular lesions are always malignant and extratesticular scrotal lesions are always benign is a simplistic statement that erroneously minimizes the significance of extratesticular scrotal masses and their diagnosis. Yet, disease in the extratesticular space is commonly encountered by clinicians and radiologists and is often a source of uncertainty in diagnosis and management. Given the embryologically rooted complex anatomy of this region, a wide range of pathologic conditions is possible. Radiologists may not be familiar with some of these conditions; further, many of these lesions can have a specific sonographic appearance, allowing accurate diagnosis that can minimize surgical intervention. Lastly, malignancies can occur in the extratesticular space-although this is less common than in the testicles-and proper recognition of findings that warrant additional imaging or surgery is critical in optimizing outcomes. The authors present a compartmental anatomic framework for differential diagnosis of extratesticular scrotal masses and provide a comprehensive illustrative display of many of the pathologic conditions that can be encountered to familiarize radiologists with the sonographic appearances of these lesions. They also review management of these lesions and scenarios where US may not be definitive in diagnosis and selective use of scrotal MRI can be helpful. ^© RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Infarcts and ischemia in the abdomen: an imaging perspective with an emphasis on cross-sectional imaging findings

Infarcts and ischemia of abdominal organs may present with acute abdominal pain, and early diagnosis is crucial to prevent morbidity and mortality. Unfortunately, some of these patients present in poor clinical conditions to the emergency department, and imaging specialists are crucial for optimal outcomes. Although the radiological diagnosis of abdominal infarcts is often straightforward, it is vital to use the appropriate imaging modalities and correct imaging techniques for their detection. Additionally, some non-infarct-related abdominal pathologies may mimic infarcts, cause diagnostic confusion, and result in delayed diagnosis or misdiagnosis. In this article, we aimed to outline the general imaging approach, present cross-sectional imaging findings of infarcts and ischemia in several abdominal organs, including but not limited to, liver, spleen, kidneys, adrenals, omentum, and intestinal segments with relevant vascular anatomy, discuss possible differential diagnoses and emphasize important clinical/radiological clues that may assist radiologists in the diagnostic process.

Mesotheliomas and Benign Mesothelial Tumors: Update on Pathologic and Imaging Findings

A diverse spectrum of benign entities and malignant neoplasms originate from the monotonous mesothelium that lines the serosal membranes of the pleural, pericardial, and peritoneal cavities. The mesothelium of myriad sites shows a common origin from the lateral plate mesoderm; primary mesothelial tumors thus demonstrate similar pathogenesis, imaging findings, and treatment options. Significant changes have been made in the 2021 World Health Organization (WHO) classification schemata of the pleural and pericardial tumors on the basis of recent advances in pathology and genetics. While malignant mesotheliomas are biologically aggressive malignancies that occur primarily in patients exposed to asbestos with attendant poor survival rates, well-differentiated papillary mesothelial tumors and adenomatoid tumors charter a benign clinical course with an excellent prognosis. Mesothelioma in situ is a newly characterized entity represented by recurrent unexplained pleural effusions without any identifiable mass at imaging or thoracoscopy. Immunohistochemical markers based on BAP1, MTAP, CDKN2A, and TRAF7 gene mutations help differentiate diffuse mesotheliomas from benign mesothelial proliferations and localized mesotheliomas. Cross-sectional imaging modalities, including US, CT, MRI, and fluorine 18-fluorodeoxyglucose (FDG) PET/CT, permit diagnosis and play a major role in staging and assessing surgical resectability. Imaging studies are invaluable in providing noninvasive and quantitative assessment of tumor response in patients with unresectable disease. Owing to significant overlap in patient characteristics and pathomorphology, accurate diagnosis based on advanced histopathology techniques and genetic abnormalities is imperative for optimal management and prognostication. While patients with nonepithelioid pleural mesotheliomas benefit from immunotherapy, novel targeted therapies for CDKN2A-, NF2-, and BAP1-altered mesotheliomas are under consideration. ^© RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

Ultrasound and Magnetic Resonance Imaging of Burned-Out Testicular Tumours: The Diagnostic Keys Based on 48 Cases

The spontaneous regression of testicular germ-cell tumours is a rare event whose mechanisms have yet to be elucidated. In the majority of published cases, tumour regression is concomitant with the metastatic development of the disease. Residual lesions, often referred to as burned-out testicular tumours (BOTTs), are difficult to diagnose due to the paucity of published data, especially in the field of imaging. The aim of this article is to describe the radiological signs of BOTTs on multimodal ultrasound and multiparametric MRI from a series of 48 patients whose diagnosis was confirmed histologically. The demographic, clinical and laboratory characteristics of the patients are studied, as well as the data of the imaging examinations, including conventional scrotal ultrasound, shear-wave elastography, contrast-enhanced ultrasound (CEUS) and multiparametric MRI. A total of 27 out of 48 patients were referred for investigation of primary testicular lesion following the discovery of retroperitoneal metastases, 18/48 patients were referred because of lesions suspected on an ultrasound that was performed for an infertility work-up, and 3/48 were referred because of scrotal clinical signs. Of these last 21 patients (infertility work-up/scrotal clinical sign), 6 were found to be metastatic on the extension work-up. Of the 48 orchiectomy specimens, tumour involution was complete in 41 cases, and a small active contingent remained in 7 cases, with 6 suspected upon advanced US and MRI. Typically, BOTTs appear on a conventional ultrasound as ill-delineated, hypoechoic and hypovascular nodular areas. Clustered microliths (60.4%) and macrocalcifications (35.4%) were frequent. Shear-wave elastography showed areas of focal induration (13.5 ± 8.4 vs. 2.7 ± 1.2 kPa for normal parenchyma, p < 0.01) in 92.5% of the patients for whom it was performed, and contrast ultrasonography demonstrated hypoperfusion of these lesions. Of the 42 MRIs performed, BOTTs corresponded to nodules on T2-weighted sequences (hyposignal) with significantly increased ADC values compared with healthy parenchyma (2 ± 0.3 versus 1.3 ± 0.3 × 10−3 mm2/s, p < 0.01) and an enhancement defect after injection. This enhancement defect overlapped the lesions visible on T2-weighted sequences in most cases. In the case of predominant partial regression, an enhanced portion after contrast injection was visible on MRI in all seven patients of our series, and in six of them a focal diffusion restriction zone was also present. Spontaneously involuted testicular germ-cell tumours have specific radiological signs, and all of the mentioned examinations contribute to this difficult diagnosis, even histologically, because there is no tumour cell left. These signs are similar whether the patient is initially symptomatic metastatic or whether the discovery is fortuitous on the occasion of an infertility work-up, and whatever the seminomatous or non-seminomatous nature of the germ-cell tumour, when this can be determined. The appearance of regressed germ-cell tumours is often trivialized, which can lead to the wrong diagnosis of an extra gonadal germ-cell tumour (in metastatic patients) or of scarring from an acute event such as trauma or infection, which is not recognized or forgotten. In our series, two patients had an unrecognized diagnosis in their history, with local and/or distant recurrence. An improvement in diagnosing burned-out tumours, combining advanced US and MRI, is necessary in order to optimize patient management, with special attention paid to asymptomatic patients, to prompt extension screening and orchiectomy with analysis of the whole testis. This may reveal a persistent viable tumour or lesions of germinal neoplasia in situ, which are precursors of testicular germ-cell tumours.

An Overview of the Role of Multiparametric MRI in the Investigation of Testicular Tumors

Simple Summary

Although conventional ultrasonography remains the primary imaging modality for the assessment of testicular tumors, multiparametric MRI of the scrotum, which combines morphologic and functional data, serves as a powerful adjunct. Based on the recommendations issued by the Scrotal and Penile Imaging Working Group of the European Society of Urogenital Radiology, scrotal MRI is strongly recommended after equivocal US findings. In cases of testicular masses, the main clinical indications are as follows: lesion characterization when sonographic findings are non-diagnostic, discrimination between germ-cell and non-germ-cell testicular tumors, local staging of testicular tumors in patients who are candidates for testis-sparing surgery, and preoperative histological characterization of testicular germ-cell tumors in selected cases. This article aims to provide an overview of the role of multiparametric MRI in the investigation of testicular tumors.

Abstract

Conventional ultrasonography represents the mainstay of testis imaging. In cases in which ultrasonography is inconclusive, scrotal MRI using a multiparametric protocol may be used as a useful problem-solving tool. MRI of the scrotum is primarily recommended for differentiating between benign and malignant testicular masses when sonographic findings are ambiguous. This technique is also accurate in the preoperative local staging of testicular tumors and, therefore, is recommended in patients scheduled for testis-sparing surgery. In addition, MRI may provide valuable information regarding the histological characterization of testicular germ-cell tumors, in selected cases. Scrotal MRI may also help in the differentiation between testicular germ-cell neoplasms and non-germ-cell neoplasms. Axial T1-weighted imaging, axial and coronal T2-weighted imaging, axial diffusion-weighted imaging, and coronal subtracted dynamic contrast-enhanced imaging are the minimum requirements for scrotal MRI. A variety of MRI techniques—including diffusion tensor imaging, magnetization transfer imaging, proton MR spectroscopy, volumetric apparent diffusion coefficient histogram analysis, and MRI-based radiomics—are being investigated for testicular mass characterization, providing valuable supplementary diagnostic information. In the present review, we aim to discuss clinical indications for scrotal MRI in cases of testicular tumors, along with MRI findings of common testicular malignancies.

The Diagnostic Value of the Added MR Imaging of the Scrotum in the Preoperative Workup of Sonographically Indeterminate Testicular Lesions—A Retrospective Multicenter Analysis

Background: The purpose of this study was to retrospectively analyze the diagnostic accuracy of magnetic resonance imaging (MRI) examinations of the scrotum in comparison with standard ultrasound (US) and histopathology. Methods: A retrospective multi-center analysis of MRI examinations of the scrotum performed between 06/2008 and 04/2021 was conducted. Results: A total of n = 113 patients were included. A total of 53 histopathologies were available, with 52.8% malignant and 50.9% benign findings. Related to histopathology, imaging was true negative, false negative, false positive, and true positive in 4.1%, 2.1%, 25.0% and 37.5% for standard ultrasound (US) and 9.1%, 1.8%, 25.5% and 43.6% for MRI. Sensitivity, specificity, positive predictive value and negative predictive value were 94.7%, 20.0%, 36.0% and 88.9% for US and 85.7%, 72.8%, 52.1% and 93.7% for MRI, respectively. Benign lesions were significantly smaller than malignant ones in standard US (p = 0.001), histopathology (p = 0.001) and MRI (p = 0.004). The size of malignant tumors did not differ significantly between histopathology and standard US (0.72) and between histopathology and MRI (p = 0.88). Conclusions: MRI shows good sensitivity and specificity for the estimation of testicular tumors in this collective. Benign lesions are significantly smaller than malignant ones. Both MRI and US can estimate the size of malignant tumors adequately.

Imaging of Pediatric Testicular and Para-Testicular Tumors: A Pictural Review

Pre- and post-pubertal testicular tumors are two distinct entities in terms of epidemiology, diagnosis and treatment. Most pre-pubertal tumors are benign; the most frequent are teratomas, and the most common malignant tumors are yolk-sac tumors. Post-pubertal tumors are similar to those found in adults and are more likely to be malignant. Imaging plays a pivotal role in the diagnosis, staging and follow-up. The appearance on ultrasonography (US) is especially helpful to differentiate benign lesions that could be candidates for testis-sparing surgery from malignant ones that require radical orchidectomy. Some specific imaging patterns are described for benign lesions: epidermoid cysts, mature cystic teratomas and Leydig-cell tumors. Benign tumors tend to be well-circumscribed, with decreased Doppler flow on US, but malignancy should be suspected when US shows an inhomogeneous, not-well-described lesion with internal blood flow. Imaging features should always be interpreted in combination with clinical and biological data including serum levels of tumor markers and even intra-operative frozen sections in case of conservative surgery to raise any concerns of malignity. This review provides an overview of imaging features of the most frequent testicular and para-testicular tumor types in children and the value of imaging in disease staging and monitoring children with testicular tumors or risk factors for testicular tumors.

Testicular tumors: discriminative value of conventional MRI and diffusion weighted imaging

To explore the feasibility of using conventional MRI features combined with apparent diffusion coefficient (ADC) values for the differential diagnosis of testicular tumors.A total of 63 patients with pathologically confirmed testicular tumors were enrolled in this study. In particular, there were 46 cases of malignant lesions and 17 cases of benign lesions. All patients underwent conventional magnetic resonance imaging (MRI) and diffusion weighted imaging. Multivariate logistic regression models and receiver operating characteristic curves were constructed to assess diagnostic accuracies.T2-homogeneity, intratumoral septa, and peritumoral infiltration were more common in the malignant group, and capsule sign was more common in the benign group (P < .05 for all). The mean ADC value of the malignant group was lower than that of the benign group (P < .05). When the ADC value ≤ 0.90 × 10-3 mm2/s, the diagnosis tended to be malignancy. The conventional MRI model could achieve better diagnostic accuracy than ADC values alone (P < .05). Compared with the conventional MRI model, the specificity and accuracy of the full model (ADC and conventional MRI model) increased by 9.8% and 3.2%, respectively. T2-homogeneity and T2-hypointensity were more common in seminoma and lymphoma, cystic changes were more common in nonseminomatous germ cell tumor (NSGCT), and intratumoral septa was more common in seminoma (P < .05 for all). The ADC value of NSGCT was larger than seminoma, and lymphoma was the smallest (P < .05 for all). Cystic changes, T2-hypointensity, intratumoral septa, and ADC value were independent factors for differentiating the seminoma, NSGCT, and lymphoma subgroups.A combination of conventional MRI features and ADC values can improve the diagnostic efficiency for differentiating benign and malignant testicular tumors, and can additionally distinguish different subtypes of malignant testicular tumors.

Ultrasonography of the scrotum: Revisiting a classic technique

Conventional US is the primary imaging modality for the evaluation of the scrotum, due to its high resolution, availability, cost-effectiveness and absence of ionizing radiation. Grayscale and color Doppler US provide a comprehensive assessment of scrotal diseases. The technique represents the mainstay for imaging of acute scrotum. US is highly accurate in the detection, localization and characterization of scrotal masses. Multiparametric US, including conventional US, contrast-enhanced US and tissue elastography has improved the diagnostic performance of the technique in the assessment of testicular diseases. MRI represents a valuable supplemental imaging tool for the investigation of scrotal pathology, mainly recommended in cases of indeterminate US findings. Recommendations recently issued by the European Society of Urogenital Radiology Scrotal and Penile Imaging Working Group (ESUR-SPIWG) refer to the use of scrotal sonography for the evaluation of pathologic entities, including testicular microlithiasis, small, non-palpable incidentally detected testicular masses, varicocele and scrotal trauma. In this review, the technical specifications for scrotal US and the normal sonographic findings are presented. Grayscale and color Doppler US findings of common acute scrotal diseases and scrotal masses are discussed. The complimentary role of multiparametric US and scrotal MRI is addressed. ESUR-SPIWG's guidelines are also reviewed.

The Value of Contrast-Enhanced Ultrasound (CEUS) in Differentiating Testicular Masses: A Systematic Review and Meta-Analysis

Ultrasound (US) still represents the mainstay of scrotal imaging. However, contrast-enhanced ultrasound (CEUS) is a relatively novel, but increasingly utilized diagnostic modality. In consequence, we performed a systematic review (SR) and pooled meta-analysis to investigate the diagnostic performance of CEUS in the evaluation of testicular masses (TM). A SR up to June 2021 was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The diagnostic performance of CEUS was evaluated basing on two different endpoints: neoplastic vs. non-neoplastic and malignant vs. benign TM. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) from eligible studies were pooled and summary receiver operating characteristic (SROC) curves were constructed for each endpoint. Overall, six qualified studies were deemed suitable for this meta-analysis. Diagnostic performance of CEUS showed an accuracy of 0.96 in detecting neoplastic masses (sensitivity of 0.89, PPV of 0.85, specificity of 0.62, and NPV of 0.69) and an accuracy of 0.96 in detecting malignant masses (sensitivity of 0.86, PPV of 0.73, specificity of 0.87, and NPV of 0.91). Taken together, CEUS may represent a promising minimally invasive diagnostic tool for characterization of TM, since it allows clinicians to identify neoplastic lesions and exclude malignant tumor.

Unusual Presentation of a Testicular Lymphoma Mimicking a Missed Testicular Torsion: A Case Report

Testicular lymphoma is an uncommon testicular tumor that usually presents as a painless mass. It usually shows hypervascularity on color Doppler ultrasound (US) and a mild enhancement on enhanced CT or MRI. We present an unusual case of a testicular lymphoma mimicking a missed testicular torsion in a 67-year-old male patient with right scrotal swelling and intermittent pain for 2 months. Color Doppler US demonstrated the absence of vascularity in the enlarged right testis, and the initial diagnosis was a missed testicular torsion. CT demonstrated a poorly enhancing mass rather than a missed testicular torsion with enhanced small nodular foci at the periphery. The final pathological diagnosis was testicular lymphoma.

Sclerosing liposarcoma of epididymis: Role of chemical shift magnetic resonance imaging

Sclerosing liposarcoma of epididymis is a rare extratesticular scrotal tumor with variable prognosis. Ultrasonography is the initial imaging modality of choice for the evaluation of scrotal mass and helps to differentiate testicular and extratesticular masses, thereby narrowing down the differential diagnosis. Magnetic resonance imaging with its excellent soft tissue resolution can help in the further characterization of the nature of the tumor. In this case report, we highlight the role of chemical shift imaging in making a confident preoperative diagnosis of liposarcoma thereby guiding optimal and timely management.

Scrotal leiomyoma: An uncommon cause of chronic scrotal swelling

Leiomyoma is a benign tumor that arises from smooth muscle. It may be encountered at any part of the body especially the uterus. However, scrotal localization is very uncommon, hence it often requires radiologic and pathology correlation to establish an accurate diagnosis and make optimal decisions for subsequent treatment. We present a case of an 82-years-old male, presenting with a left scrotal mass. Ultrasound and MRI demonstrated a left paratesticular mass. Surgery was then indicated and pathology results were consistent with a scrotal leiomyoma.

Identifying the deceiver: the non-neoplastic mimickers of genital system neoplasms

Tumors of the genital system are common and imaging is of crucial importance for their detection and diagnosis. Several non-neoplastic diseases may mimic these tumors and differential diagnosis may be difficult in certain cases. Misdiagnosing non-neoplastic diseases as tumor may prompt unnecessary medical treatment or surgical interventions. In this article, we aimed to present the imaging characteristics of non-neoplastic diseases of the male and female genital systems that may mimic neoplastic processes. Increasing awareness of the imaging specialists to these entities may have a severe positive impact on the management of these patients.

When to ask for an MRI of the scrotum

Background

Multiparametric MRI (mpMRI) of the scrotum has been established as a useful second‐line diagnostic tool for the investigation of scrotal diseases. Recently, recommendations on clinical indications for scrotal MRI were issued by the Scrotal and Penile Imaging Working Group of the European Society of Urogenital Radiology.

Objective

To update current research on when to ask for an MRI of the scrotum.

Methods

PubMed database was searched for original articles and reviews published during 2010–2021.

Results

Eighty‐three articles fulfilled the search criteria. Scrotal MRI is mainly recommended after inconclusive US findings or inconsistent with the clinical examination and should be asked in the following cases: differentiation between intratesticular and paratesticular lesions (in rare cases of uncertain US findings), characterization of paratesticular and intratesticular lesions (when US findings are indeterminate), discrimination between germ cell and sex cord‐stromal testicular tumors, local staging of testicular malignancies (in patients planned for testis‐sparing surgery), differentiation between seminomas and non‐seminomatous tumors (when immediate chemotherapy is planned and orchiectomy is delayed), assessment of acute scrotum and scrotal trauma (rarely needed, in cases of non‐diagnostic US findings) and detection and localization of undescended testes (in cases of inconlusive US findings). Although preliminary data show promising results in the evaluation of male infertility, no established role for mpMRI still exists.

Conclusion

Multiparametric MRI of the scrotum, by assessing morphologic and functional data represents a valuable problem‐solving tool, helping to improve our understanding on the nature of scrotal pathology and the process of spermatogenesis. The technique may improve patient care and reduce the number of unnecessary surgical procedures.

The potential role of MR based radiomic biomarkers in the characterization of focal testicular lesions

How to differentiate with MRI-based techniques testicular germ (TGCTs) and testicular non-germ cell tumors (TNGCTs) is still under debate and Radiomics may be the turning key. Our purpose is to investigate the performance of MRI-based Radiomics signatures for the preoperative prediction of testicular neoplasm histology. The aim is twofold: (i), differentiating TGCTs and TNGCTs status and (ii) differentiating seminomas (SGCTs) from non-seminomatous (NSGCTs). Forty-two patients with pathology-proven testicular neoplasms and referred for pre-treatment MRI, were retrospectively enrolled. Thirty-two out of 44 lesions were TGCTs. Twelve out of 44 were TNGCTs or other histologies. Two radiologists segmented the volume of interest on T2-weighted images. Approximately 500 imaging features were extracted. Least Absolute Shrinkage and Selection Operator (LASSO) was applied as method for variable selection. A linear model and a linear support vector machine (SVM) were trained with selected features to assess discrimination scores for the two endpoints. LASSO identified 3 features that were employed to build fivefold validated linear discriminant and linear SVM classifiers for the TGCT-TNGCT endpoint giving an overall accuracy of 89%. Four features were employed to build another SVM for the SGCT-SNGCT endpoint with an overall accuracy of 86%. The data obtained proved that T2-weighted-based Radiomics is a promising tool in the diagnostic workup of testicular neoplasms by discriminating germ cell from non-gem cell tumors, and seminomas from non-seminomas.

Imaging of Scrotal Tumors

음낭 종양은 고환, 부고환, 정삭, 고환막 등에서 발생하며 악성 가능성을 평가하는데 가장 중요한 요소는 병변의 위치이다. 추가적인 영상 소견과 임상 정보를 종합하여 효과적으로 진단 할 수 있다. 초음파검사는 표재성 기관인 음낭을 관찰하기 용이하며, 우수한 영상 품질을 바탕으로 병변의 유무뿐만 아니라 위치와 성상까지 확인 가능하다. 초음파검사로 감별이 어려울 경우에는 자기공명영상을 이용하여 지방, 출혈, 섬유화, 조영증강 등 추가적인 종양의 특징을 확인하는 것이 진단에 도움이 된다. 전산화단층촬영은 고환암의 병기결정이나 복강 내 미하강고환의 위치를 탐색하는데 유용하다. 본 종설에서는 고환 내외에서 발생하는 음낭 종양의 영상 소견을 살펴보고자 한다.

Scrotal leiomyoma: a rare cause of scrotal swelling

Background

Leiomyomas are benign smooth muscle tumours predominantly found in the uterus. Rarely, they may be located in the ovaries, scrotum, bladder, lungs, vascular structures and spermatic cord.

Case presentation

We managed a 39-year-old man who presented with a year history of progressive right-sided hemiscrotal swelling. The right scrotal mass was excised, and histology showed scrotal leiomyoma.

Conclusion

Scrotal leiomyoma is very rare and challenging to diagnose pre-operatively as a cause of scrotal swelling, but it is amenable to surgical excision.

Proton MR Spectroscopy in Assessing the Biochemical Milieu of Human Testes

Proton magnetic resonance spectroscopy (MRS), considered a connection between metabolism and anatomic and functional information provided by standard MRI, gives information on various tissue metabolites and their pathologic changes. Recently, proton MRS has been added as an adjunct tool to the multiparametric protocol of scrotal MRI, providing a new insight into the extremely complex biochemical milieu of normal and abnormal testes. This article reviews proton MR spectra of normal testes, showing age and bilateralism dependence. Disturbances of various metabolic pathways in testes of infertile men resulting in alterations of metabolite peaks are discussed. Preliminary data on proton MR spectra of testicular mass lesions are presented. LEVEL OF EVIDENCE: 5. TECHNICAL EFFICACY STAGE: 5.

Diagnostic clues, pitfalls, and imaging characteristics of '-celes' that arise in abdominal and pelvic structures

'-Celes' is an ancient Greek language suffix that means 'tumor,' 'hernia,' 'swelling,' or 'cavity.' There are many '-celes' in the abdomen and pelvis that may be encountered during routine imaging interpretation, including santorinicele, choledochocele, ureterocele, lymphocele, mucocele, rectocele, cystocele, peritoneocele, varicocele, spermatocele, hydrocele, hematocele, pyocele and syringocele. Most '-celes' are detected incidentally at imaging for other clinical indications, but some deserve more attention due to a range of clinical symptoms or functional disorder that can adversely affect patient quality of life. The objective of this article was to address all of the '-celes' that a general radiologist and abdominal radiologist should know and be able to recognize. Imaging characteristics, diagnostic clues, and pitfalls have been provided to improve diagnostic accuracy and patient outcomes.

Imaging of scrotal masses

Testicular cancer is responsible for approximately 0.1% of all cancer deaths in the USA, and seminoma is the most common type of testicular tumor. Ultrasonography is the primary imaging modality for accessing testicular and extratesticular lesions, while magnetic resonance imaging can be used for problem solving in lesion characterization in certain cases. CT imaging is usually performed for retroperitoneal staging of testicular cancer metastasis and follow-up after treatment. Extratesticular masses are common, yet rarely malignant. Imaging plays an important role in primary diagnosis of testicular cancer and differentiating it from common non-neoplastic findings. The purpose of this article is to review various imaging findings in testicular and extratesticular masses.

Role of MRI in Staging of Penile Cancer

Penile cancer is one of the male-specific cancers. Accurate pretreatment staging is crucial due to a plethora of treatment options currently available. The 8^th edition American Joint Committee on Cancer-Tumor Node and Metastasis (AJCC-TNM) revised the staging for penile cancers, with invasion of corpora cavernosa upstaged from T2 to T3 and invasion of urethra downstaged from T3 to being not separately relevant. With this revision, MRI is more relevant in local staging because MRI is accurate in identifying invasion of corpora cavernosa, while the accuracy is lower for detection of urethral involvement. The recent European Urology Association (EAU) guidelines recommend MRI to exclude invasion of the corpora cavernosa, especially if penis preservation is planned. Identification of satellite lesions and measurement of residual-penile-length help in surgical planning. When nonsurgical treatment modalities of the primary tumor are being considered, accurate local staging helps in decision-making regarding upfront inguinal lymph node dissection as against surveillance. MRI helps in detection and extent of inguinal and pelvic lymphadenopathy and is superior to clinical palpation, which continues to be the current approach recommended by National Comprehensive Cancer Network (NCCN) treatment guidelines. MRI helps the detection of "bulky" lymph nodes that warrant neoadjuvant chemotherapy and potentially identify extranodal extension. However, tumor involvement in small lymph nodes and differentiation of reactive vs. malignant lymphadenopathy in large lymph nodes continue to be challenging and the utilization of alternative contrast agents (superparamagnetic iron oxide), positron emission tomography (PET)-MRI along with texture analysis is promising. In locally recurrent tumors, MRI is invaluable in identification of deep invasion, which forms the basis of treatment. Multiparametric MRI, especially diffusion-weighted-imaging, may allow for quantitative noninvasive assessment of tumor grade and histologic subtyping to avoid biopsy undersampling. Further research is required for incorporation of MRI with deep learning and artificial intelligence algorithms for effective staging in penile cancer. Level of Evidence: 5 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:1612-1629.

MRI findings of an atypical testicular epidermoid cyst: A case report

INTRODUCTION

Typical testicular epidermoid cysts (TECs) manifestate as a target sign or onion skin sign on ultrasonography and magnetic resonance (MR) imaging. Clinicians are increasingly aware of the imaging characteristics of typical TECs, which allow accurate diagnosis and successful treatment while preserving the testicle, but atypical TECs are likely to be misdiagnosed as a malignant intratesticular neoplasm, leading to complete testicular resection.

PATIENT CONCERNS

A 26 year-old male patient complained of a painless enlargement of the left testicle that had been present for 1 month. The patient had no recent medical history of scrotal trauma or systemic infection.

DIAGNOSIS

A round 48 mm × 45 mm × 43 mm mass was seen inside the left testicle. T2-weighted images of the lesion showed a thin hypointense capsule. T1-weighted images of the lesion showed a hyperintense nodule on the cyst wall, which appeared hypointense on T2-weighted and SPAIR images. After Gd-DTPA injection, the lesion was not enhanced; however, the nodule was enhanced on THRIVE images. These manifestations were consistent with a benign intratesticular lesion, and MR imaging diagnosed atypical TEC, which was confirmed by pathology after surgery.

INTERVENTIONS

The patient was treated with organ-sparing surgery with testicular enucleation.

OUTCOMES

The patient was re-examined with ultrasonography 3 months after surgery. The left residual testicular tissue appeared normal, and reproductive function was preserved.

CONCLUSION

Urologists must be aware of the clinical and MR imaging characteristics of atypical TECs and the utility of preoperative MR imaging for the diagnosis of testicular lesions to ensure that organ-sparing surgery is performed rather than unnecessary orchiectomy.

Leydig Cell Hyperplasia Mimicking a Testicular Tumour in a Patient with Klinefelter Syndrome

Background

Klinefelter syndrome (KS) is the most common sex-chromosomal disorder in males. Frequently under-recognized, it occurs in 1 in 500-600 male births. It is caused by the inheritance of at least one additional X chromosome from either parent. Patients often have uncommon or atypical malignancies.

Patient

We describe the case of a 35-year-old man with 47XXY KS and previous cryptorchidism, presenting with a painful testicular mass. Histology confirmed Leydig cell hyperplasia.

Discussion

Cryptorchidism is an established risk factor for testicular tumours and occurs six times more commonly in KS than in the general population. Despite this, large epidemiological studies have shown a reduced burden of testicular cancer in these patients. The presentation of a hypoechoic lesion on ultrasound will prompt consideration of testicular tumours, however orchalgia represents an atypical presentation. In patients with KS, Leydig cell hyperplasia is a much more common entity and should be considered early in the differential diagnosis.

LEARNING POINTS

The differential diagnosis of a testicular mass in Klinefelter syndrome includes malignancy and nodular Leydig cell hyperplasia.Diagnosis can be challenging, both radiologically and histologically.Orchalgia is atypical in Leydig cell hyperplasia.

Testicular epidermoid cysts: a reevaluation

Background

Testicular epidermoid cysts (TECs) are rare benign testicular neoplasms. As TECs are rarely associated with germ cell tumours (GCTs), the understanding of biological behaviour and clinical management of TEC is unresolved.

Methods

We retrospectively searched the files of patients treated for testicular neoplasms and germ cell cancer in the time from 2000 to 2017. Those with TEC were subjected to closer review looking to clinical and histological features, and to results from imaging with ultrasonography (US), contrast enhanced sonography (CEUS) and magnetic resonance imaging (MRI).

Results

Among 589 patients undergoing surgery for testicular tumour, nine simple TECs were identified (1.5, 95% confidence intervals 0.53–2.50%). Median age was 26 years. Imaging revealed sharply demarcated roundish lesions with avascular central areas. Eight patients underwent testis-sparing excision with no recurrence ensuing. One had orchiectomy because of large size of the mass. Histologically, TECs consisted of cornifying squamous cell epithelium and no accompanying germ cell neoplasia in situ. Two additional cases (0.3% of all) required orchiectomy because these TECs were associated with ipsilateral GCT.

Conclusions

TEC is usually a benign lesion that can safely be diagnosed with US, CEUS and MRI due to its roundish shape and its avascular centre. Histologically, this TEC corresponds to the prepubertal-type teratoma unrelated to germ cell neoplasia in situ of the 2016 WHO classification. The other subtype of TEC that is associated with invasive GCT represents a teratoma of postpubertal-type. From a clinical point of view it could be easier to differentiate between a “simple TEC” which is benign (prepubertal type) and a “complex TEC” which is malignant because of its association with invasive GCT.

A case of primary testicular lymphoma with continuous spread along the gonadal vein and spermatic cord

Primary testicular lymphoma (PTL) is a rare form of non-Hodgkin's lymphoma more prevalent in males aged over 60 years old. PTL has a tendency to disseminate to systemic extranodal sites, however there has been a rare continuous spread involving the gonadal vein and spermatic cord. This method of dissemination has been described in 3 previous cases, and this case report presents another such case where such spread was noted, in a patient with a previous history of seminoma. Knowledge of this method of spread may increase the index of suspicion of PTL on cross-sectional imaging.

MR imaging of paratesticular bilateral leiomyoma: A case report

Paratesticular leiomyoma is a rare benign neoplasm that may arise from smooth muscle cells contained in either the epididymis, the spermatic cord, or the tunica albuginea. Usually patients present a palpable, asymptomatic mass, with a higher prevalence among the fourth and fifth decade of life. In this case report we describe a 57-year-old man with bilateral scrotal palpable masses evaluated with ultrasound and magnetic resonance imaging that were suggestive for leiomyoma. The lesions were surgically removed and pathology revealed no signs of malignancy confirming the diagnostic hypothesis of leiomyoma. Ultrasound is considered the imaging modality of choice for the initial evaluation of testicular masses since it allows an accurate localization (ie testicular vs paratesticular) and can identify signs of malignancy. Magnetic resonance imaging is less frequently performed but can considerably improve lesion characterization.

MRI of testicular malignancies

Although testicular carcinoma represents approximately only 1% of solid neoplasms in men, it is the most common malignancy between young men. The two main histologic categories are testicular germ cell tumors (TGCTs), including seminomas and nonseminomas, accounting for 90-95% of testicular neoplasms and sex cord-stromal tumors. Scrotal MRI, including a multiparametric protocol, has been proposed as a valuable supplemental imaging technique in the investigation of testicular pathology. Recently, the Scrotal and Penile Imaging Working Group appointed by the board of the European Society of Urogenital Radiology has produced recommendations on when to perform scrotal MRI. Regarding intratesticular masses, MRI of the scrotum may be used for their characterization, when US findings are indeterminate and for local staging of TGCTs, when organ-sparing surgery is planned. Differentiation between seminomas and nonseminomas is possible based on MRI features, when clinically needed. Scrotal MRI may also help in differentiating between TGCTs and nongerm cell tumors. Functional information based on diffusion-weighted imaging and dynamic contrast-enhanced MRI data improve testicular mass lesion characterization. Preliminary observations on diffusion tensor imaging, magnetization transfer imaging, and proton MR spectroscopy bring about new data in the understanding of testicular microstructure and pathophysiology.

Paratesticular sarcomas: a case series and literature review

Paratesticular soft tissue tumours are remarkably rare entities, with malignant subtypes accounting for approximately 30%. Due to the paucity of cases, a consensus on the best treatment has not yet been reached, presenting a diagnostic and therapeutic challenge for clinicians. Although rare, three such cases presented to the care of our institution serving a population of approximately 400,000 in the space of 13 months. These were three gentlemen, aged 54, 82 and 86 years old, presenting with left sided testicular swellings. Ultrasound in each case confirmed an extratesticular mass. Only the second gentleman complained of associated pain, however he had experienced scrotal trauma in the preceding weeks. Only one patient had suspicions of metastatic disease, with a 9 mm pulmonary nodule on computed tomography. All patients underwent a radical inguinal orchidectomy with high ligation of the spermatic cord, in keeping with best accepted guidelines. Histology confirmed a well-differentiated liposarcoma, a dedifferentiated liposarcoma and a leiomyosarcoma respectively, all high grade. One gentleman returned to theatre for re-excision of margins. Our case series emphasises the need for full multidisciplinary team specialist sarcoma input, as well as radical resection with judicious margins in order to reduce the risk of local recurrence, in the treatment of these rare tumours.

Sonographically indeterminate scrotal masses: how MRI helps in characterization

Magnetic resonance imaging (MRI) of the scrotum represents a useful supplemental imaging technique in the characterization of scrotal masses, particularly recommended in cases of nondiagnostic ultrasonographic findings. An accurate characterization of the benign nature of scrotal masses, including both intratesticular and paratesticular ones may improve patient management and decrease the number of unnecessary radical surgical procedures. Alternative treatment strategies, including follow-up, lesion biopsy, tumor enucleation, or organ sparing surgery may be recommended. The aim of this pictorial review is to present how MRI helps in the characterization of sonographically indeterminate scrotal masses and to emphasize the key MRI features of benign scrotal masses.

Lesions Without Borders: Scrotal Lesions That Involve Both the Intratesticular and Extratesticular Regions

OBJECTIVE

Differentiation of scrotal lesions is often dictated by whether they are intraor extratesticular. However, these regions are not entirely isolated, and disease processes can span both spaces. We review a variety of lesions that can involve both regions, describe the relevant anatomy, and illustrate their imaging appearances.

CONCLUSION

Identification of involvement of both intra- and extratesticular regions by a single process can narrow the differential considerations and help arrive at the correct diagnosis.

MR Imaging of the Testicular and Extratesticular Tumors: When Do We Need?

Testicular ultrasound is typically the first-line imaging examination in evaluating scrotal pathology. However, MR imaging can often provide valuable additional information, especially when ultrasound and/or clinical examinations are inconclusive. This is particularly evident when encountering testicular or paratesticular lesions, where accurate localization and characterization are paramount for management and prognosis. After reviewing normal scrotal anatomy as seen on MR imaging and offering a sample imaging protocol, the article describes specific indications for scrotal MR imaging and highlights imaging findings unique to various benign and malignant causes.

Well-differentiated papillary mesothelioma of tunica vaginalis testis of unknown malignant potential: Sonographic appearance

Paratesticular mesothelioma is a rare differential diagnosis in the presence of scrotal hydrocele. A 17-year-old boy presented with a 3-year history of progressive hydrocele. Sonography revealed a large left paratesticular mass within the hydrocele. Serum tumor markers were negative. Left hydrocelectomy was performed and pathological analysis of the epididymal mass revealed a well-differentiated papillary mesothelioma. We discuss the sonographic and pathological findings of this rare neoplasm.