The origin of testicular microliths

Clinical and seminal parameters associated with testicular microlithiasis and its severity in males from infertile couples

STUDY QUESTION

Is there an association of testicular microlithiasis (TM) and its severity with testicular dysfunction in men from infertile couples?

SUMMARY ANSWER

The presence of ≥5 testis microcalcifications per sonogram at the scrotal ultrasonography (US) of infertile males was associated with a more severe testicular dysfunction as compared to males with limited, or without, TM.

WHAT IS KNOWN ALREADY

TM, representing an incidental finding in the scrotal US, is associated with male infertility and a higher risk for testicular cancer as compared to that in infertile males without TM. Still, there are unresolved questions on the relation between TM severity and testicular dysfunction in infertile men, as well as on the identification of risk factors for TM.

STUDY DESIGN, SIZE, DURATION

This study was an observational, retrospective, case-control investigation involving males who underwent clinical evaluation, measurement of reproductive hormones, seminal analysis and scrotal US as part of diagnostic work-up for couple infertility at an andrology clinic, between January 2004 and December 2018. One hundred patients, out of the 2112 scored men, were found to have TM during the US evaluation. One hundred male partners from 100 infertile couples without TM, comprising the control group, were selected through a matched analysis by age and date of evaluation to reduce the confounding effect of both age and technique variability all along the long period of observation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

TM was defined as limited TM (LTM) or classical TM (CTM), when the maximum number of hyperecogenic spots per sonogram was <5 or ≥5, respectively. CTM, LTM and control groups were compared for clinical variables, serum levels of FSH, LH, and total testosterone, as well for semen parameters and scrotal US features.

MAIN RESULTS AND THE ROLE OF CHANCE

After the exclusion of cases with testicular nodules to eliminate the possible confounding effect of testis cancer on testicular dysfunction, cases with CTM showed a lower mean testis volume (P = 0.03) and a lower sperm concentration (P = 0.03) as compared to the other two groups. A higher FSH level was observed in the CTM group compared to the LTM group (P = 0.02) and in controls (P = 0.009). The multiple logistic regression analysis showed that only a smaller testicle volume exhibited an independent significant association with a higher odds of detecting CTM (odds ratio = 0.84, 95% CI: 0.75–0.94; P = 0.02). No significant differences were observed between groups in the prevalence of risk factors for testicular cancer, or in the prevalence of conditions associated with TM.

LIMITATIONS, REASONS FOR CAUTION

The retrospective design of the study did not allow conclusions to be drawn about the possible underlying links in the associations of TM with defective spermatogenesis.

WIDER IMPLICATIONS OF THE FINDINGS

Males from infertile couples who exhibit a reduced testicular volume should undergo scrotal US, independent of sperm parameters, to exclude CTM and, eventually, testis cancer, although the association of CTM and current or future testis cancer risk is not yet clear. Evidence is provided here demonstrating that the presence of LTM has no clinical relevance in males from infertile couples.

STUDY FUNDING/COMPETING INTEREST(S)

Investigation was funded by Ministero dell’Università e della Ricerca, PRIN 2018, Italy. The authors have not declared any competing interests.

TRIAL REGISTRATION NUMBER

N/A

Sertoli cell tumour in a pet rabbit (Oryctolagus cuniculus): histological and immunohistochemical characterization

The present study describes a case of a spontaneous, unilateral Sertoli cell tumour (SCT) in a 6-year-old pet rabbit. The rabbit was presented with a palpable, unilateral, subcutaneous left inguinal mass, consistent with the suspected clinical diagnosis of neoplasia developing within the retained testis in the inguinal canal. The intrascrotal contralateral testis was palpable, but reduced in volume. The rabbit underwent orchiectomy and both the testes were collected, formalin-fixed, and submitted for histopathological examination. Microscopically, the enlarged testis was effaced by an intratubular SCT in which numerous intratubular microliths were evident. The contralateral testis was severely atrophied. Immunohistochemical stains showed neoplastic Sertoli cells that were diffusely positive for vimentin and anti-Müllerian-Hormone and multifocally positive for cytokeratins and desmin. Eighteen months after the surgery, the rabbit showed no clinical signs of disease. This is the first report of a spontaneously occurring rabbit SCT histologically described and immunohistochemically investigated.

The Diagnostic Value of Ultrasound in Differentiating Obstructive from Nonobstructive Azoospermia Based on the Presence of Testicular Microlithiasis

A total of 32 azoospermic men aged 24 to 54 years were studied perspectively at King Hussein Medical Center.Patient history, semen analyses, hormonal status, and testicular volume were analyzed.High-resolution ultrasound scan machine with a 7.0-MHz transducer was performed on all patients to detect testicular microlithiasis.Testicular biopsy was per formed on all patients.Based on the clinical findings outlined in this article, it is concluded that testicular ultrasound examination is a simple, rapid, and non-invasive diagnostic tool in evaluating the testicular body.Based on testicular volume, hormonal status, presence, and degree of testicular microlithiasis, ultrasound scanning has a significant role in differentiating OA from NOA.

Clinical aspects of testicular microlithiasis in boys: a review

OBJECTIVE

After review of the pediatric literature, we report on the prevalence of testicular microlithiasis and its relation with benign and malign entities. We provide a guideline for the management of boys with testicular microlithiasis.

MATERIALS AND METHODS

The databases searched were Medline, Web of Science, Embase and the Cochrane Library. Data on the rates of testicular microlithiasis were collected and from each study information was extracted on the study population according to country, study design, diagnostic method, type of patient, number of patients, age, associated anomalies, additional diagnostic methods and follow-up information. From the 472 articles, we selected 126 articles as potentially relevant, of which 57 were included.

RESULTS

In asymptomatic boys, the prevalence of testicular microlithiasis is 4.2% and in symptomatic referrals it is 1.6%. The development of a testicular malignancy is occasionally reported after diagnosis of testicular microlithiasis. The management of boys with testicular microlithiasis varies widely. Most authors recommend regular self-examination, and some perform testicular ultrasound and/or screen tumor markers.

CONCLUSION

The prevalence of testicular microlithiasis in boys varies between 1.1% and 4.2%. For follow-up, regular self-examination is advised from the age of 15 years.

Testicular microlithiasis: Is there an agreed protocol?

This review addresses the issues on etiopathogenesis of testicular microlithiasis (TM), associated clinical entities, evaluation and follow-up of patients with TM. A literature search of Medline/PubMed was carried out using the keywords 'testicular microlithiasis' and 'testicular calcifications' for published data in English language on TM from 1970 to 2006. TM is an uncommon entity among adult males, resulting from intratubular calcifications. The reported incidence of TM is highly variable. With the increasing frequency of ultrasound examination in scrotal and testicular conditions and with the advent of high frequency transducers, TM is increasingly being reported. TM is associated with many benign and malignant conditions of testes but the possible association of TM with testicular cancer has been a matter of concern. Though a few sporadic cases of testicular malignancies have been reported, it is believed that a conservative approach is warranted in the absence of high risk factors, in view of the low risks for invasive cancers. There is no uniform protocol for the evaluation and follow-up of the patients with TM. Those with high risk factors like contralateral testicular tumour, chromosomal anomalies, gonadal dysgenesis, cryptorchidism and definite ultrasound pattern of TM should be advised to have further evaluation. Incidentally detected asymptomatic TM during ultrasound examination does not warrant aggressive measures and it can be followed with self examination.

Occurrence of testicular microlithiasis in androgen insensitive hypogonadal mice

BACKGROUND

Testicular microliths are calcifications found within the seminiferous tubules. In humans, testicular microlithiasis (TM) has an unknown etiology but may be significantly associated with testicular germ cell tumors. Factors inducing microlith development may also, therefore, act as susceptibility factors for malignant testicular conditions. Studies to identify the mechanisms of microlith development have been hampered by the lack of suitable animal models for TM.

METHODS

This was an observational study of the testicular phenotype of different mouse models. The mouse models were: cryptorchid mice, mice lacking androgen receptors (ARs) on the Sertoli cells (SCARKO), mice with a ubiquitous loss of androgen ARs (ARKO), hypogonadal (hpg) mice which lack circulating gonadotrophins, and hpg mice crossed with SCARKO (hpg.SCARKO) and ARKO (hpg.ARKO) mice.

RESULTS

Microscopic TM was seen in 94% of hpg.ARKO mice (n=16) and the mean number of microliths per testis was 81+/-54. Occasional small microliths were seen in 36% (n=11) of hpg testes (mean 2+/-0.5 per testis) and 30% (n=10) of hpg.SCARKO testes (mean 8+/-6 per testis). No microliths were seen in cryptorchid, ARKO or SCARKO mice. There was no significant effect of FSH or androgen on TM in hpg.ARKO mice.

CONCLUSION

We have identified a mouse model of TM and show that lack of endocrine stimulation is a cause of TM. Importantly, this model will provide a means with which to identify the mechanisms of TM development and the underlying changes in protein and gene expression.

Association between testicular microlithiasis and primary malignancy of the testis: our experience and review of the literature

PURPOSE

The aims of this study were to evaluate the association of testicular microlithiasis with testicular neoplasm, to assess the accuracy of ultrasonography (US) in comparison with histology in detecting microlithiasis, and to identify the prevalent cytohistological features that accompany testicular cancer.

MATERIALS AND METHODS

Between 2004 and 2005, 14 patients were referred to us for US examination, 13 of whom underwent surgery for testicular cancer. Their age ranged from 19 to 43 years, except for one patient aged 60. US findings and histological examination were compared to assess the accuracy of US in detecting microlithiasis associated with testicular cancer.

RESULTS

In two patients (15.3%), microlithiasis had been detected in a previous US examination, and two patients (15.3%) had altered sperm function. At US examination, testicular cancer was associated with microlithiasis in seven out of 13 patients (53.8%) (the distribution pattern of microlithiasis was intranodular in two, perinodular in two and both intra-and perinodular in three), and colour-Doppler US showed perinodular and intranodular vascularity. Histological evaluation identified nine seminomas, two mixed germ-cell tumours, one embryonal carcinoma, one yolk-sac tumour and one benign Sertoli-cell tumour. In nine (69.2%) patients, microlithiasis was confirmed at histologic evaluation, and its distribution was intranodular in two, perinodular in five and both intra-and perinodular in two. Tubular hyalinisation was demonstrated in 12 out of 13 patients (92.3%).

CONCLUSIONS

Testicular microlithiasis and poor sperm function represent risk factors for testicular cancer: in our study, 30.6% of the patients who developed cancer presented these features. At US examination, testicular microlithiasis is often associated with testicular cancer (53.8%). A high accuracy has been demonstrated for US in detecting microlithiasis (53.8%) compared with histological evaluation (69.2%). At histology, tubular hyalinisation (92.3% of cases) is, with testicular microlithiasis, the most frequent finding in the parenchyma adjacent to testicular cancer.

Primary testicular lesions are associated with testicular germ cell tumors of adult men

The present study aims to establish the nature and frequency of testicular lesions in the parenchyma adjacent to testicular germ cell tumors (TGCT) to improve understanding of the factors involved in the development of testicular cancer. Fifty-three cases of TGCT that were fixed in both neutral-buffered formalin and Bouin solution, allowing for the nuclear characterization of Sertoli cells (SCs), were included in this study. In each case, at least 3 sections of different areas of preserved parenchyma surrounding the TGCT were studied. We found Leydig cell hyperplasia, microlithiasis, angiopathy, adenomatous hyperplasia of the rete testis, SC nodules, SC dysgenesis and involution, SC-only tubules, tubular atrophy, adluminal compartment lesions, hypospermatogenesis associated with spermatocyte sloughing, spermatogonial maturation arrest, and hypertrophic and multinucleated spermatogonia. These lesions were found in regions both adjacent and far away from the tumoral mass, and abnormal seminiferous tubules were found intermingled with those showing complete spermatogenesis, suggesting that these lesions are primary and existed before the development of the tumor. Our study suggests that SCs might play a more important role in the development of testicular tumors than previously thought. Our data supports the hypothesis that there is an abnormal differentiation of SCs, caused either by genetic anomalies or by environmental agents during fetal life. This abnormal SC differentiation may cause not only primary spermatogenesis failure and spermatogenesis arrest at different levels, but may also contribute to the poor differentiation of gonocytes into spermatogonia. The abnormal gonocyte differentiation might favor the development of dysplastic germ cells that may later transform into intratubular germ cell neoplasia, unclassified type.

Microlithiasis of the epididymis and the rete testis

Testicular microlithiasis is a well-defined clinical and pathologic entity easily diagnosed through testicular echography; however, its association with cancer and infertility is now under debate. Many efforts have been done in recent years to clarify the spectrum of lesions observed in testicular microlithiasis, but no published data as to the existence of a possible microlithiasis of the epididymis and the rete testis have been found. We have observed microlithiasis of the epididymis and the rete testis in surgical (8 epididymis and 6 testis) and autopsy specimens (12 cases). In decreased order of frequency, microliths of the proximal spermatic way were seen in rete testis, epididymal duct, and efferent ducts. Intraluminal, subepithelial, and interstitial microliths were localized along these segments of the spermatic way. Subepithelial microliths were the most frequently found. A granulomatous reaction around the interstitial epididymal microliths, mimicking malacoplakia, was observed in 1 case. The differential diagnosis of microliths includes corpora amilacea, Michaelis-Gutmann bodies, calcium deposits, hyaline globules, and parasites, like the giant kidney worm Dioctophyme renale. In infants and young adults, microlithiasis of the epididymis and the rete testis is frequently associated with alterations in the development of the proximal spermatic way. In elderly adults, it is related to ischemia and obstruction of the spermatic way.

Raman Spectroscopic Analysis Identifies Testicular Microlithiasis as Intratubular Hydroxyapatite

PURPOSE

As diagnosed by ultrasonography, testicular microlithiasis is associated with various benign and malignant conditions. The molecular constitution of these microliths is largely unknown. Raman spectroscopy provides detailed in situ information about the molecular composition of tissues and to our knowledge it has not been applied to gonadal microliths. We analyzed the molecular composition of gonadal microlithiasis and its surrounding region using Raman spectroscopy in malignant and benign conditions.

MATERIALS AND METHODS

Multiple microliths from 6 independent samples diagnosed with gonadal microlithiasis by ultrasound and histologically confirmed were investigated by Raman spectroscopy. The samples included 4 testicular parenchyma samples adjacent to a germ cell tumor (4 seminomas), a gonadoblastoma of a dysgenetic gonad and testicular biopsy of a subfertile male without malignancy.

RESULTS

Raman spectroscopic mapping demonstrated that testicular microliths were located within the seminiferous tubule. Glycogen surrounded all microliths in the samples associated with germ cell neoplasm but not in the benign case. The molecular composition of the 26 microliths in all 6 conditions was pure hydroxyapatite.

CONCLUSIONS

Microliths in the testis are located in the seminiferous tubules and composed of hydroxyapatite. In cases of germ cell neoplasm they co-localize with glycogen deposits.

[Intratesticular calcifications: clinical significance]

OBJECTIVE

[corrected] To evaluate the clinical-pathological significance of the intratesticular calcification.

MATERIAL AND METHODS

We analyzed by scrotal U.S., transducer 6.5 Mhz, the patients that consulted about testicular painful, infertility or intrascrotal deformity. Biopsy was effectuated when detected size modification of testicles, and central or focal calcifications. Also was done the classics tumoral markers. We founds 16 patients with microlithiasis over 24 testicles with these pathology. Previous antecedents: infertility 6 cases, testicular devolvulations surgery 5c, bilateral orchidopexy 3c and unilateral epididymitis 2c. The calcifications was classified in: peripheric or central follow-up 26.4 months.

RESULTS

Associated pathology: a) Bilateral cryptorchidism: 4 testicles. b) Testicular tumors: 5 testicles. These tumors were biopsed: 3 seminomas, 1 embryonary carcinoma and 1 ca in situ. Both with negative biologic markers. The association with testicular tumor had an incidence of 20.83%. The central localization was detected in the 5 tumors, while the peripheric were 4 testis (cryptorchidism) and 15 with aspect of "snow storm". Histopathologically was observed eosinophilic bodies, with calcified nucleus, but not a exclusive features.

CONCLUSIONS

Is a benign condition, casual, whose clinical significance is a still enigma. The association with testicular tumor is 20.83% and associated pathology is 33%. We proposed a testicular biopsy in cases of microlithiasis focal, central or with previous pathology.

Identification of seminiferous tubule aberrations and a low incidence of testicular microliths associated with the development of azoospermia

OBJECTIVE

To evaluate the use of percutaneous testicular sperm aspiration in the assessment of azoospermia and its association with seminiferous tubule microliths.

DESIGN

Case report.

SETTING

Tertiary care fertility center in a university hospital.

PATIENT(S)

Male undergoing infertility evaluation.

INTERVENTION(S)

Testicular biopsy and percutaneous testicular aspiration.

MAIN OUTCOME MEASURE(S)

Serum hormone analysis, sperm concentration in semen, spermatogenesis in samples from testicular biopsies and aspirations, and microlith composition.

RESULT(S)

A patient presented for infertility evaluation with a history of severe oligospermia that progressed to azoospermia. The serum testosterone concentration (357 ng/dL) and LH concentration (9.2 mIU/mL) were normal and the serum FSH concentration (18.3 mIU/mL) was elevated. Testicular biopsy results indicated spermatogenic hypoplasia with limited spermatozoa. Seminiferous tubules obtained by percutaneous testicular aspiration were structurally aberrant, with multiple diverticula. Microliths averaging 120 microm in diameter were observed within and blocking the seminiferous tubules. The microliths were composed of calcium phosphate (hydroxyapatite) in both the core and peripheral regions. Electron microscopy revealed a high degree of collagen-like material within the peripheral zone.

CONCLUSION(S)

The presence of seminiferous tubule microliths is associated with the development of azoospermia. In patients with a low incidence of seminiferous tubule microliths and aberrant seminiferous tubule architecture, percutaneous testicular aspiration may provide a diagnostic advantage over testicular biopsy.

Testicular biopsy. Contemporary interpretation

Biopsy of the testis is not universally accepted in contrast with biopsies of other organs. The pathologist studies and reports on the pathophysiology of the testicular biopsy specimen. Methodology requires the inclusion of qualitative and quantitative studies, the evaluation of the lesion's evolution (prognosis), and, often, therapeutic advice regarding treatment. Cooperation between pathologists and clinicians optimizes the utility of the biopsy for the patient.