State of the art in germ cell tumor imaging

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.

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.

Seminoma in a Transverse Testicular Ectopia: A Rare Case Report

Transverse testicular ectopia (TTE) is an extremely rare congenital anomaly of the testis, characterized by migration of one testis toward the contrary hemiscrotum. TTE is usually associated with other testicular abnormalities such as persistent Mullerian duct syndrome, hypospadias, true hermaphroditism, and scrotal anomalies. Testicular sonography is the main initial diagnostic modality, followed by magnetic resonance imaging of the scrotum. These imaging modalities are important for determination of TTE and characterization of the testicular lesions. This case report provides the high-resolution ultrasonography, Doppler ultrasonography, magnetic resonance imaging, and diffusion-weighted imaging findings of a young man with seminoma in the transverse testicular ectopia. In addition, data on tumor stiffness, obtained with point shear-wave sonoelastography, are presented.

Overview of ultrasound applications for assessing scrotal disorders

The scrotum may be affected by a plethora of different disorders such as infections, vasculopathies, trauma, and manifestations of primary and secondary malignant masses. In addition to the patient's medical history and clinical examination, ultrasound represents the imaging modality of choice to assess scrotal disorders. Time-consuming contrast-enhanced ultrasound and elastography can provide further information to distinguish between benign and malignant testicular mass lesions. The following invited Special Communication gives a comprehensive overview of differential diagnoses of the scrotum and their corresponding sonomorphologic correlates based on representative cases of the Interdisciplinary Ultrasound Center of the University Hospital Munich.

Impact of increased aspartate aminotransferase to alanine aminotransferase (De Ritis) ratio in prognosis of testicular cancer

Purpose

Imaging studies can show metastasis in testicular cancer (TCa); however, a test for risk of metastasis in TCa has not been described. The ratio of aspartate aminotransferase to alanine aminotransferase, also called the De Ritis ratio (DRR), is used for many other malignancies. We aimed to evaluate the association between preoperatively assessed DRR and prognosis in patients with TCa.

Materials and Methods

One hundred twenty-eight patients with TCa were enrolled in a retrospective study between March 2007 and January 2017. Clinical, biochemical, and pathological data were recorded. Univariate and multivariate logistic regression analyses were used. The prognostic value of DRR and the threshold value were assessed by use of receiver operating characteristic curves. Significance was defined as p<0.05.

Results

Mean follow-up was 37±9.7 months. There were 45 and 73 TCa patients with and without lymph node metastasis, respectively. Lung metastases and other solid organ metastases occurred in 14 and 4 patients, respectively. The optimal DRR threshold was 1.30 for both retroperitoneal lymph node involvement and metastasis. DRR was determined as an independent prognostic factor for retroperitoneal lymph node involvement and organ metastasis in univariate and multivariate analyses (p<0.001, p=0.006 and p=0.002, p=0.047, respectively).

Conclusions

A preoperative DRR greater than 1.30 may be an independent risk factor for retroperitoneal lymph node involvement and organ metastases in patients with TCa.

Serum Levels of MicroRNA371a-3p: A Highly Sensitive Tool for Diagnosing and Staging Testicular Germ Cell Tumours: A Clinical Case Series

INTRODUCTION

MicroRNA (miR)371a-3p was suggested to be a sensitive and specific new serum biomarker of germ cell tumours (GCTs); however, its clinical usefulness remains unproven.

PATIENTS, METHODS

In 312 consecutive cases with various testicular diseases, serum levels of miR371a-3p were measured. Measurement results became available only after completion of treatment. Five patients with testicular seminoma were selected for review because of unanticipated clinical courses.

RESULTS

In each two patients, elevated miR levels heralded undetected primary testicular GCT and metastases despite inconclusive radiological findings. In one case, a normal miR371a-3p level correctly pointed to the absence of metastases contrary to clinical assessment. In all cases, knowledge about the miR371a-3p levels would have altered the clinical management.

CONCLUSIONS

These cases highlight the exceptional usefulness of the new GCT biomarker. In contrast to classical markers, miR371a-3p can identify primary testicular GCT. The marker can aid in clinical decision making in cases with ambiguous clinical findings.

Testicular Seminoma and Its Mimics: From the Radiologic Pathology Archives

Testicular seminoma is the most common malignant tumor of the testis. It classically manifests as a painless mass. Radiologic evaluation with high-frequency ultrasonography (US) is critical for diagnosis. Seminomas are usually homogeneously hypoechoic masses at US. In challenging cases, magnetic resonance (MR) imaging may help confirm that a mass is intratesticular and provide data for local staging. Computed tomography (CT) provides valuable information for staging, including the presence and size of retroperitoneal lymph nodes. Testicular seminoma is treated with radical inguinal orchiectomy and is highly curable even at advanced stages of disease. Several neoplastic and nonneoplastic conditions may mimic testicular seminoma at imaging. Benign mimics include segmental infarction, hematoma, infection, epidermoid cyst, adrenal rests, sarcoidosis, splenogonadal fusion, and sex cord-stromal tumors. Malignant mimics include nonseminomatous germ cell tumors, lymphoma, and metastases. These conditions are individually reviewed with emphasis on features that allow differentiation from seminoma. Spermatocytic tumor, formerly known as spermatocytic seminoma, accounts for only 1% of testicular tumors. It is distinct from classic seminoma, with unique histologic, molecular, and genetic features. It affects an older patient population than classic seminoma and demonstrates indolent clinical behavior. Radiologists serve a key role in diagnosis, staging, and surveillance of patients with seminoma. A thorough knowledge of related clinical, radiologic, and pathologic findings will help the radiologist contribute to high-quality interdisciplinary care of affected patients.