Testicular ultrasound underestimates the size of small testicular masses: a radiologic-pathologic correlation study

Optimal imaging techniques across the spectrum of testicular cancer

Over the years, several imaging techniques have been used in the diagnosis and management of testicular cancer. We compartmentalize disease stages into preorchiectomy, stage 1, initial stage 2 and 3 and postchemotherapy stage 2 and 3. We then elaborate on various imaging modalities that are relevant to each of these stages. We also describe evolving imaging tools that have shown promise. We attempt to provide a comprehensive review of these techniques over the spectrum of testicular cancer.

Discriminating Malignant from Benign Testicular Masses Using Multiparametric Magnetic Resonance Imaging-A Prospective Single-Center Study

Objective: The objective of this study was to prospectively assess the extent to which magnetic resonance imaging (MRI) can differentiate malignant from benign lesions of the testis. Materials and Methods: All included patients underwent multiparametric testicular MRI, including diffusion-weighted imaging (DWI) and subtraction dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). Subsequently, all patients underwent a histopathological examination via orchiectomy or testicular biopsy/partial resection. The Kolmogorov-Smirnov test, t-test, Mann-Whitney U test, Fisher's exact test, and logistic regression were applied for statistical analysis. Results: We included 48 male patients (median age 37.5 years [range 18-69]) with testicular tumors. The median tumor size on MRI was 2.0 cm for malignant tumors and 1.1 cm for benign tumors (p < 0.05). A statistically significant difference was observed for the type (type 0-III curve, p < 0.05) and pattern of enhancement (homogeneous, heterogeneous, or rim-like, p < 0.01) between malignant and benign tumors. The minimum apparent diffusion coefficient (ADC) value was 0.9 for benign tumors and 0.7 for malignant tumors (each ×103 mm2/s, p < 0.05), while the mean ADC was 0.05. The mean ADC value was significantly lower for malignant tumors; the mean ADC value was 1.1 for benign tumors and 0.9 for malignant tumors (each ×103 mm2/s, p < 0.05). The sensitivity, specificity, positive predictive value, and negative predictive value of multiparametric MRI for differentiating malignant from benign testicular lesions were 94.3%, 76.9%, 91.7%, and 83.3%, respectively. The surgical procedures performed included orchiectomy (n = 33; 71.7%) and partial testicular resection (n = 11; 23.9%). Histopathology (HP) revealed malignancy in 35 patients (72.9%), including 26 with seminomas and 9 with non-seminomatous germ cell tumors (NSGCTs). The HP was benign in 13 (27.1%) patients, including 5 with Leydig cell tumors. Conclusions: Malignant and benign tumors differ in MRI characteristics in terms of the type and pattern of enhancement and the extent of diffusion restriction, indicating that MRI can be an important imaging modality for the accurate diagnosis of testicular lesions.

Diagnosis and management of indeterminate testicular lesions

The sophistication and accessibility of modern-day imaging result in frequent detection of small or equivocal lesions of the testes. Traditionally, diagnosis of a testicular lesion with any possibility of malignancy would usually prompt radical orchidectomy. However, awareness is growing that a substantial proportion of these lesions might be benign and that universal application of radical orchidectomy risks frequent overtreatment. Given the potentially profound effects of radical orchidectomy on fertility, endocrine function and psychosexual well-being, particularly in scenarios of an abnormal contralateral testis or bilateral lesions, organ-preserving strategies for equivocal lesions should be considered. Image-based active surveillance can be applied for indeterminate lesions measuring ≤15 mm with a low conversion rate to surgical treatment. However, these outcomes are early and from relatively small, selected cohorts, and concerns prevail regarding the metastatic potential of even small undiagnosed germ cell tumours. No consensus exists on optimal surveillance (short interval (<3 months) ultrasonography is generally adopted); histological sampling is a widespread alternative, involving inguinal delivery of the testis and excisional biopsy of the lesion, with preoperative marking or intraoperative ultrasonographic localization when necessary. Frozen section analysis in this context demonstrates excellent diagnostic accuracy. Histological results support that approximately two-thirds of marker-negative indeterminate solitary testicular lesions measuring ≤25 mm overall are benign. In summary, modern imaging detects many small indeterminate testicular lesions, of which the majority are benign. Awareness is growing of surveillance and organ-sparing diagnostic and treatment strategies with the aim of minimizing rates of overtreatment with radical orchidectomy.

Ultrasound assessment of testicular volume - An interobserver variability study

BACKGROUND

Ultrasonography measurement of the testicles and subsequent calculation of the testicular volume is recommended as a part of a standard scrotal ultrasound examination. The interobserver variability of testicular volume measurement has implications for surgical recommendations. Therefore, this study aimed to investigate the interobserver variability in the measurement of testicular volume.

METHODS

Interobserver variability was established by comparing testicular measurements performed by two observers on the same patient during the same clinical appointment. The observers were blinded to each other's measurements. Testicular volume was calculated using the Lambert formula: length x width x height x 0.71. A total of three observers, A, B and C, participated in the study. The observers had between 4 to 20 years' experience with scrotal ultrasound examinations.

RESULTS

In total, 24 patients' were included (48 testicles). The patient´s mean age was 43 years (range 19-75 years). The overall mean right testicular volume was 19.8 ml (range 7.3-31.6 ml), and the left was 20.1 ml (range 7.1-36.1 ml). The interclass correlation coefficient (ICC) between observer A and B was excellent (ICC= 0.98, CI:0.92-0.99), between observer A and C, was excellent (ICC=0.91, CI: 0.77-0.97) and between B and C good (ICC=0.82, CI:0.51-0.93).

CONCLUSION

Variability in estimating testicular volume is low, with interobserver agreement ranging from good to excellent. Ultrasound provides a highly reproducible tool to determine testicular volume.

Radiological features characterising indeterminate testes masses: a systematic review and meta-analysis

CONTEXT

The use of scrotal ultrasonography (SUS) has increased the detection rate of indeterminate testicular masses. Defining radiological characteristics that identify malignancy may reduce the number of men undergoing unnecessary radical orchidectomy.

OBJECTIVE

To define which SUS or scrotal magnetic resonance imaging (MRI) characteristics can predict benign or malignant disease in pre- or post-pubertal males with indeterminate testicular masses.

EVIDENCE ACQUISITION

This systematic review was conducted in accordance with Cochrane Collaboration guidance. Medline, Embase, Cochrane controlled trials and systematic reviews databases were searched from (1970 to 26 March 2021). Benign and malignant masses were classified using the reported reference test: i.e., histopathology, or 12 months progression-free radiological surveillance. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool (QUADAS-2).

EVIDENCE SYNTHESIS

A total of 32 studies were identified, including 1692 masses of which 28 studies and 1550 masses reported SUS features, four studies and 142 masses reported MRI features. Meta-analysis of different SUS (B-mode) values in post-pubertal men demonstrated that a size of ≤0.5 cm had a significantly lower odds ratio (OR) of malignancy compared to masses of >0.5 cm (P < 0.001). Comparison of masses of 0.6-1.0 cm and masses of >1.5 cm also demonstrated a significantly lower OR of malignancy (P = 0.04). There was no significant difference between masses of 0.6-1.0 and 1.1-1.5 cm. SUS in post-pubertal men also had a statistically significantly lower OR of malignancy for heterogenous masses vs homogenous masses (P = 0.04), hyperechogenic vs hypoechogenic masses (P < 0.01), normal vs increased enhancement (P < 0.01), and peripheral vs central vascularity (P < 0.01), respectively. There were limited data on pre-pubertal SUS, pre-pubertal MRI and post-pubertal MRI.

CONCLUSIONS

This meta-analysis identifies radiological characteristics that have a lower OR of malignancy and may be of value in the management of the indeterminate testis mass.

Management of small testicular masses: outcomes from a single-centre specialist multidisciplinary team

OBJECTIVES

To report the management outcomes of men with ≤20-mm small testicular masses (STMs) and to identify clinical and histopathological factors associated with malignancy.

PATIENTS AND METHODS

A retrospective analysis of men managed at a single centre between January 2010 and December 2020 with a STM ≤20 mm in size was performed.

RESULTS

Overall, 307 men with a median (interquartile range [IQR]) age of 36 (30-44) years were included. Of these, 161 (52.4%), 82 (26.7%), 62 (20.2%) and 2 men (0.7%) underwent surveillance with interval ultrasonography (USS), primary excisional testicular biopsy (TBx) or primary radical orchidectomy (RO), or were discharged, respectively. The median (IQR) surveillance duration was 6 (3-18) months. The majority of men who underwent surveillance had lesions <5 mm (59.0%) and no lesion vascularity (67.1%) on USS. Thirty-three (20.5%) men undergoing surveillance had a TBx based on changes on interval USS or patient choice; seven (21.2%) were found to be malignant. The overall rate of malignancy in the surveillance cohort was 4.3%. The majority of men who underwent primary RO had lesions ≥10 mm (85.5%) and the presence of vascularity (61.7%) on USS. Nineteen men (23.2%) who underwent primary TBx (median lesion size 6 mm) had a malignancy confirmed on biopsy and underwent RO. A total of 88 men (28.7%) underwent RO, and malignancy was confirmed in 73 (83.0%) of them. The overall malignancy rate in the whole STM cohort was 23.8%. Malignant RO specimens had significantly larger lesion sizes (median [IQR] 11 [8-15] mm, vs benign: median [IQR] 8 [5-10] mm; P = 0.04).

CONCLUSIONS

Small testicular masses can be stratified and managed based on lesion size and USS features. The overall malignancy rate in men with an STM was 23.8% (4.3% in the surveillance group). Surveillance should be considered in lesions <10 mm in size, with a TBx or frozen-section examination offered prior to RO in order to preserve testicular function.

Testicular Neoplasms: Primary Tumour Size Is Closely Interrelated with Histology, Clinical Staging, and Tumour Marker Expression Rates-A Comprehensive Statistical Analysis

The role of primary tumour size (TS) in the clinical course of testicular tumours is incompletely understood. We retrospectively evaluated 641 consecutive patients with testicular neoplasms with regard to TS, histology, clinical stage (CS), serum tumour marker (STM) expression and patient age using descriptive statistical methods. TS ≤ 10 mm was encountered in 13.6% of cases. Median TS of 10 mm, 30 mm, 35 mm, and 53 mm were found in benign tumours, seminomas, nonseminomas, and other malignant tumours, respectively. In cases with TS ≤ 10 mm, 50.6% had benign tumours. Upon receiver operating characteristics analysis, TS of > 16 mm revealed 81.5% sensitivity and 81.0% specificity for detecting malignancy. In subcentimeter germ cell tumours (GCTs), 97.7% of cases had CS1, and CS1 frequency dropped with increasing TS. Expression rates of all STMs significantly increased with TS. MicroRNA-371a-3p (M371) serum levels had higher expression rates than classical STMs, with a rate of 44.1% in subcentimeter GCTs. In all, TS is a biologically relevant factor owing to its significant associations with CS, STM expression rates and histology. Importantly, 50% of subcentimeter testicular neoplasms are of benign nature, and M371 outperforms the classical markers even in subcentimeter tumours.