Fibrotic lesions of the testicle: sonographic patterns mimicking malignancy

From subjective to objective: A pilot study on testicular radiomics analysis as a measure of gonadal function

BACKGROUND

The connection between testicular ultrasound (US) parameters and testicular function, including both spermato- and steroidogenesis has been largely suggested, but their predictive properties are not routinely applied. Radiomics, a new engineering approach to radiological imaging, could overcome the visual limit of the sonographer.

OBJECTIVES

This study is aimed at extracting objective testicular US features, correlating with testicular function, including both spermato- and steroidogenesis, using an engineering approach, in order to overcome the operator-dependent subjectivity.

MATERIALS AND METHODS

Prospective observational pilot study from December 2019 to December 2020 on normozoospermic subjects and patients with semen variables alterations, excluding azoospermia. All patients underwent conventional semen analysis, pituitary-gonadal hormones assessment, and testicular US, performed by the same operator. US images were analyzed by Biolab (Turin) throughout image segmentation, image pre-processing, and texture features extraction.

RESULTS

One hundred seventy US testicular images were collected from 85 patients (age 38.6 ± 9.1 years). A total of 44 first-order and advanced features were extracted. US inhomogeneity defined by radiomics significantly correlates with the andrologist definition, showing for the first time a mathematical quantification of a subjective US evaluation. Thirteen US texture features correlated with semen parameters, predicting sperm concentration, total sperm number, progressive motility, total motility and morphology, and with gonadotropins serum levels, but not with total testosterone serum levels. Classification analyses confirmed that US textural features predicted patients' classification according to semen parameters alterations.

CONCLUSIONS

Radiomics texture features qualitatively describe the testicular parenchyma with objective and reliable quantitative parameters, reflecting both the testicular spermatogenic capability and the action of pituitary gonadotropins. This is an innovative model in which US texture features represent a mirror of the pituitary-gonadal homeostasis in terms of reproductive function.

Ultrasound morphological patterns of testicular tumours, correlation with histopathology

INTRODUCTION

Ultrasound (US) plays a key role in the detection of testicular tumours. However, reliable characterisation of testicular tumours with US is difficult. The purpose of this study was to investigate the morphological patterns of testicular tumours as seen on modern US imaging and correlate these with histology.

METHODS

The imaging features of 50 testicular tumours were analysed and compared with histology. The US appearance was categorized into 15 distinct morphological patterns.

RESULTS

Patient's age ranged from 0.5 to 85 years. Of the 50 tumours in our series, 49 were malignant. Nearly half of the malignancies were seminomatous germ cell tumours (SGCTs). Tumours ranged in size from 10 to 130 mm with considerable overlap of size between tumours of different histological type. Even small (10 mm) tumours in our cohort were malignant. SGCTs demonstrated a narrower range of morphological appearances than non-seminomatous germ cell tumours (NSGCTs). Calcification was common in both SGCT and NSGCTs. Multicomponent cystic-solid appearance was only seen in NSGCTs.

CONCLUSION

The differentiation of testicular tumours with US continues to be challenging. In this paper, we have demonstrated the diverse morphological patterns of testicular neoplasms and have proposed the study of tumour morphological features as a promising research direction.

Testicular ultrasound score: A new proposal for a scoring system to predict testicular function

Background

Testicular ultrasound (US) is routinely employed in the evaluation of reproductive and sexual function. However, its use for characteristics other than testicular volume is hampered by a lack of information on the prognostic value of its findings, which to date have only been incorporated in a score proposed by Lenz et al in 1993.

Objectives

We sought to explore whether testicular US examination can predict the quality of spermatogenesis and provide information on testicular endocrine function.

Materials and methods

We retrospectively reviewed 6210 testicular US examinations, finally selecting examinations from 2230 unique men. The following variables were considered: bitesticular volume and testicular asymmetry, parenchymal echotexture, echogenicity and presence of microlithiasis, solid lesions and varicocoele. Concurrent fasting hormonal data were available for 1160 men, while 979 had a semen sample available from the same day as the US examination.

Results

We derived a new US score, termed TU score, that can predict both impaired spermatogenesis (AUC 0.73, sensitivity 72%, specificity 61%, P < .001) and hypogonadism (AUC 0.71, sensitivity 71%, specificity 53%, P < .001) more accurately than the Lenz's score. In a multivariate analysis, a reduced sperm composite index (defined as total spermatozoa × total motility × normal forms) was independently predicted by bitesticular volume and by inhomogeneous echotexture, while hypogonadism was independently predicted also by reduced echogenicity and presence of microlithiasis.

Discussion and conclusions

We describe the testicular US characteristics that are independently associated with impaired spermatogenesis and hypogonadism and propose the TU score as a simple screening method for use in subjects referred for testicular US.

Pseudoneoplastic lesions of the testis and paratesticular structures

Pseudotumors or tumor-like proliferations (non-neoplastic masses) and benign mimickers (non-neoplastic cellular proliferations) are rare in the testis and paratesticular structures. Clinically, these lesions (cysts, ectopic tissues, and vascular, inflammatory, or hyperplastic lesions) are of great interest for the reason that, because of the topography, they may be relevant as differential diagnoses. The purpose of this paper is to present an overview of the pseudoneoplasic entities arising in the testis and paratesticular structures; emphasis is placed on how the practicing pathologist may distinguish benign mimickers and pseudotumors from true neoplasia. These lesions can be classified as macroscopic or microscopic mimickers of neoplasia.

Ultrasound of the Scrotum

Ultrasound is a vital adjunct to clinical examination in diagnosing scrotal disease, as a number of different processes may present similarly. Potential applications range from the acute emergency to long-term screening as well as cases in which a distinct scrotal abnormality may or may not be palpable. Differentiating acute epididymitis/epididymoorchitis from testicular torsion is possible sonographically, thereby guiding appropriate medical or surgical management. Distinguishing between cystic, solid, or complex scrotal masses is readily performed with this modality. It clearly depicts simple versus complex hydroceles and determines the presence of underlying testicular or epididymal disease. Not only is ultrasound the best imaging modality for longitudinal screening in patients (testicular microlithiasis, cryptorchidism) at risk for testicular tumors, it also provides valuable information in the infertile male by documenting the presence or absence of a varicocele.

Ultrasound of the scrotum

Ultrasound plays an important role in the diagnostic workup of scrotal diseases. It can differentiate a testicular mass from an extratesticular mass and determine whether the mass is cystic, solid, or complex. Using this information a likely diagnosis can be ascertained. In the acute scrotum, acute epididymitis/epididymo-orchitis can in most cases be distinguished from testicular torsion. Following scrotal trauma, surgery is needed to salvage the testis if there is testicular disruption and ultrasound can help with this diagnostic dilemma. When a large hydrocele is present, ultrasound allows evaluation of the underlying testis and epididymis and it can detect varicoceles, especially in the infertile male. In patients at risk for a testicular tumor (cryptorchid testis, testicular microlithiasis), ultrasound is the best imaging modality for follow-up. CT, MRI, and nuclear medicine scanning may be necessary for further evaluation of scrotal diseases and this will be briefly addressed.

Clinical importance of a unilateral striated pattern seen on sonography of the testicle

OBJECTIVE

The purpose of this study was to determine the clinical importance of a unilateral striated pattern seen on high-resolution sonography of a testicle on the basis of follow-up imaging.

CONCLUSION

In the absence of relevant clinical findings or an abnormal signal on color-flow or power Doppler sonography, a striated pattern of a testicle appears to have no clinical importance. It is presumed to represent fibrosis, and the patient most likely can be followed up clinically and sonographically rather than having to undergo surgical exploration.

Prevalence and significance of heterogeneous testes revealed on sonography: ex vivo sonographic-pathologic correlation

OBJECTIVE

Heterogeneous or mottled testes in middle-aged or elderly men are often encountered on sonography. To determine the prevalence, cause, and significance of this finding, we examined 50 testes (25 pairs) from autopsy specimens with sonography and gross and microscopic pathology.

SUBJECTS AND METHODS

Testicles were obtained at autopsy from a series of 25 male cadavers (age range, 16-80 years; mean, 62 years). Eight subjects had a history of cancer. Ex vivo sonography was performed and two board-certified radiologists graded the testis by consensus as normal, heterogeneous, or "other abnormality" (cyst, dilated rete, echogenic focus, or halo). Microscopic pathology was obtained in all abnormal (sonographic or gross pathologic) testes. The severity of tubular sclerosis (atrophy) was graded on a scale of 0-3+ by a uropathologist. RESULTS; No testicular tumors were detected. Sonography revealed normal testes in 33 specimens, heterogeneous in seven specimens, and other in 10 specimens (one cyst, two dilated rete, three halos, and seven echogenic foci). Histology revealed that all seven cases of mottled or heterogeneous testis corresponded to extensive (grades 2 and 3) regions of tubular sclerosis (atrophy). A new sonographic finding of the "halo" was attributable to a thickened, adherent tunica albuginea.

CONCLUSION

The prevalence of heterogeneous testes in this elderly population was 14% and represented seminiferous tubule atrophy and sclerosis. The prevalence of clinically occult testicular cancer or metastases in this autopsy subject group was nil. Older patients with a mottled or heterogeneous testis, normal color Doppler flow, and no palpable abnormality probably do not need sonographic follow-up.

The changes seen on high-resolution ultrasound in orchitis

Orchitis and epididymitis are increasingly common lesions encountered in general practice. The clinical diagnosis of inflammation of the testis can be difficult as 10% of neoplasms present acutely with features of inflammation or torsion. The radiological diagnosis is also difficult as the changes seen on ultrasound, whether diffuse or focal, acute or chronic, have to be differentiated from the changes seen with tumours of the testis. The purpose of this review is to describe and illustrate the evolving changes seen in orchitis with reference to the anatomy and pathophysiology of testicular inflammation. We hope that recognition of this pattern may lead to a more confident diagnosis and appropriate management decisions.

Ultrasound assessment of testicular and paratesticular masses

This article discusses the role of ultrasound in the workup of patients with suspected or palpable scrotal masses. By characterizing masses as intra- or extratesticular, the differential diagnosis can be narrowed considerably. Neoplasm is the primary concern with intratesticular masses, although non-neoplastic conditions, such as hematoma and focal orchitis, may have a similar appearance. Correlation with the patient's history is essential. The sonographic presentation of extratesticular pathology, including varicocele and masses of epididymal origin, is also described.

Radical orchidectomy and benign testicular conditions

The records of 149 patients who underwent testicular exploration for suspected malignancy were reviewed retrospectively. Malignancy was confirmed in 102 patients but benign pathology was noted in 47. Patients with benign disease were older, more likely to be Asian, gave a longer history and on examination were less likely to have a testicular mass. Increased levels of tumour markers, and ultrasonographic and operative appearance of the testis were highly predictive; with ultrasonography having a sensitivity of 100 per cent but a specificity of only 36 per cent for malignancy. Preoperative ultrasonography and an awareness of the potentially benign nature of many lesions with the use of frozen-section biopsy, where appropriate, may allow a decrease in the currently high rate of unnecessary orchidectomy without missing testicular malignancy.