Intratubular germ cell neoplasia in testicular teratomas and epidermoid cysts. Correlation with prognosis and possible biologic significance

Differential expression of preferentially expressed antigen in melanoma (PRAME) in testicular germ cell tumors - A comparative study with SOX17

The accurate identification of different components in testicular germ cell tumors (GCT) is essential for tailoring treatment and informing the clinical prognosis. PRAME (preferentially expressed antigen in melanoma), a member in the family of cancer testis antigens, plays critical roles in regulating pluripotency and suppressing somatic/germ cell differentiation in seminomas (SEM). To investigate the potential diagnostic value of PRAME in testicular GCT, here we comparatively examined the expression patterns of PRAME and SOX17 by immunohistochemistry in both pure and mixed GCT. Tissue microarrays constructed from 66 pure or mixed GCT were examined, including 25 seminomas (13 pure and 12 mixed), 35 embryonal carcinomas (EC; 7 pure and 28 mixed), 23 teratomas (TER; 10 pure and 13 mixed), 15 yolk sac tumors (YST; 1 pure and 14 mixed), and 5 choriocarcinomas (CC; 1 pure and 4 mixed), with 11 germ cell neoplasia in situ (GCNIS) and 6 normal testicular tissue as controls. The expression levels of PRAME or SOX17 were evaluated by a scoring system counting for intensity and extent of staining. PRAME nuclear expression was present in 92% (23/25) of SEM, including all 13 pure SEM, and 10 out of 12 seminomatous component of mixed GCT. In contrast, all EC and TER were completely negative for PRAME, and focal expression was demonstrated in 33.3% of YST and 20% of CC. As for SOX17, 96% of SEM and 73% of YST stained positively, whereas EC and CC were negative. Focal nuclear positivity was identified in the epithelial cell component of 17.4% (4/23) of TER. We found the sensitivity of PRAME to detect SEM to be comparable to SOX17, although SOX17 staining is more diffuse and stronger in the majority of cases. The specificity of PRAME for SEM appeared to be superior to that of SOX17 (92% versus 81%). In conclusion, PRAME is preferentially expressed in SEM or within the seminomatous component of mixed GCT with only focal variable expression in YST and CC, but shows no expression in EC and TER. These findings suggest that PRAME can be explored as a diagnostic marker for SEM.

EAU-ESPU pediatric urology guidelines on testicular tumors in prepubertal boys

BACKGROUND

Testicular tumors in prepubertal boys account for 1-2% of all solid pediatric tumors. They have a lower incidence, a different histologic distribution and are more often benign compared to testicular tumors in the adolescent and adult group. This fundamental difference should also lead to a different approach and treatment.

OBJECTIVE

To provide a guideline for diagnosis and treatment options in prepubertal boys with a testicular mass.

METHOD

A structured literature search and review for testicular tumors in prepubertal boys was performed. All English abstracts up to the end of 2019 were screened, and relevant papers were obtained to create the guideline.

RESULTS

A painless scrotal mass is the most common clinical presentation. For evaluation, high resolution ultrasound has a detection rate of almost 100%, alpha-fetoprotein is a tumor marker, however, is age dependent. Human chorionic gonadotropin (HCG) was not a tumor marker for testis tumors in prepubertal boys.

CONCLUSION

Based on a summary of the literature on prepubertal testis tumors, the 2021 EAU guidelines on Pediatric Urology recommend a partial orchiectomy as the primary approach in tumors with a favorable preoperative ultrasound diagnosis.

Case Report: Rare Presentation of Mixed Germ Cell Tumor in an Infant

The estimated incidence of pediatric testis tumor is 0.5-2.0 per 100,000 children, accounting for 1-2% of all pediatric tumors. Mixed germ cell tumors (MGCT) in prepubertal males are exceedingly rare, with only one previous case report found in the literature. We report a case of a MGCT in an infant. For prepubertal males, GCTs typically present with a painless scrotal mass, though trauma, testis torsion and hydrocele are also common presentations. Similar to such tumors in postpubertal males, ultrasonography, computed tomography, and tumor markers are integral to determine the best treatment. The patient described in this report presented with a painless scrotal mass. Following orchiectomy, the patient was found to have MGCT that was limited to the testis. With prudent management, these patients tend to have favorable prognoses.

Rare benign and malignant testicular lesions: histopathology and management

PURPOSE OF REVIEW

The presence of vascular solid tumors within the testicle is considered to be malignant until proven otherwise. However, it is prudent for clinicians to be aware of rare benign and malignant intratesticular lesions as management can differ from the established treatment algorithms for germ-cell tumors.

RECENT FINDINGS

Utilizing certain histopathologic findings can assist with the diagnosis of rare testis tumors. Often times the tumor subtypes are an important consideration in the grading and classification of the disease, which drives management. The multidisciplinary management of rare malignant testis tumors at an experienced center seems to provide optimal patient outcomes. Regardless of the primary treatment, prolonged follow-up for sex cord stromal tumors and other rare testis malignancies is advocated due to the delayed metastatic potential.

SUMMARY

The clinical presentation of rare benign and malignant testis tumors is often similar to that of germ-cell tumors. Likewise, imaging characteristics are also often indistinguishable. However, the management of these rare tumors is often different from the well established treatment algorithms of germ-cell tumors. To that end, it is important for the practicing urologist to be familiar with the current principles of these tumor characteristics and the management.

Prospective molecular and morphological assessment of testicular prepubertal-type teratomas in postpubertal men

In 2016, the World Health Organization classification system of testicular tumors included the new entity prepubertal-type teratoma based on its morphological and molecular profile, and the realization that these tumors may occur in postpubertal men. For treatment and prognostic purposes, it is important to distinguish prepubertal-type teratoma from the usual postpubertal-type teratoma, because the former is benign unlike the latter. The distinction may be challenging. In this study, we investigated clinical, morphological, and molecular criteria for distinguishing prepubertal-type teratoma from postpubertal-type teratoma in a prospective series of pure testicular teratomas. All cases of pure teratoma in postpubertal men assessed at Barts Health NHS Trust or in consultation since the introduction of routine investigation of chromosome 12p status in 2010 were reviewed. Morphological features suggestive of prepubertal-type teratoma were observed in 14 out of 35 cases. All underwent molecular testing and none displayed 12p amplification. Mean tumor size was 16 mm (range 7-28 mm). None had associated germ cell neoplasia in situ or significant atrophy. Four incorporated a well-differentiated neuroendocrine tumor, 1-2 mm in size. Of the ten patients with follow-up information, none have recurred or metastasized. Twenty-one of the 35 cases were diagnosed as postpubertal-type teratoma, mean tumor size 40 mm (range 6-90 mm). One case underwent molecular testing: a tumor of pure skeletal muscle differentiation and possessed 12p amplification. Three cases presented with clinical metastases. Eight cases contained immature areas, ten cases had associated germ cell neoplasia in situ, and 17 cases had severe atrophy of the parenchyma. One case with neither germ cell neoplasia in situ nor atrophy showed necrosis. We conclude that both morphological and molecular features are of help in differentiating prepubertal-type teratoma from postpubertal-type teratoma. In nearly all postpubertal-type teratomas, molecular testing was unnecessary, and merely confirmed the morphological impression in the prepubertal-type teratomas. Our study confirmed the high incidence of well-differentiated neuroendocrine tumors in the prepubertal-type.

[Testicular tumors in prepubertal boys-organ preservation possible more often than expected]

In prepubertal boys, testicular tumors are rare with an incidence between 2 and 5/million. In contrast to testicular tumors in adolescents and adults, more than 2/3 of these tumors are benign. Unfortunately, in Germany in most cases, only malignant tumors (usually yolk sac tumors) are reported to the study center (MAKEI IV and now V). Therefore, the incidence in Germany is unknown. Since the introduction of polychemotherapy in the 1970s, the prognosis of malignant testicular tumors has improved enormously and has become a curable disease, even in the case of recurrence. Today the orchiectomy, which was usually carried out in the past, appears to be no longer justified in most prepubertal boys due to the high incidence of benign tumors. It has been shown in various studies that organ-sparing surgery in germ cell tumors (epidermoid cysts, teratoma); gonadal stoma tumors (Sertoli, Leydig and granulosa cell tumors) and cystic lesions (intratesticular cysts and tubular ectasia of the rete testis) is reliable and safe. In cases with preoperative significantly increased AFP (caution: norm values not valid in the first year of life) and a clear testicular tumor in the ultrasound (yolk sac tumor) or if no testicular parenchyma is sonographically detectable, orchiectomy can still be carried out. Today orchiectomies in prepubertal boys should be an exception and the reasons for an orchiectomy must be well documented.

Histology, 12p status, and IMP3 expression separate subtypes in testicular teratomas

Introduction

Two types of testicular teratomas are distinguished by the current WHO classification. Prepubertal-type teratomas are benign, while postpubertal-type teratomas are considered malignant with metastatic potential, and are associated with germ cell neoplasia in situ. Prepubertal-type cases have been reported in the adult testis potentially causing confusion and overtreatment. Demonstration of the absence of 12p abnormalities with fluorescence in situ hybridization may facilitate diagnosis. Recently, IMP3 has emerged as a potential marker of malignancy in this context.

Aims

The aim of this study was to assess histological characteristics, IMP3 expression and the presence of 12p abnormalities of pure testicular teratomas.

Results

Thirty-seven cases were studied, 7 patients were children and 30 were adults. Six out of 7 pediatric cases showed no 12p abnormality and were IMP3 positive. Seventy-four percent and 79% of adult cases showed 12p abnormalities and IMP3 expression, respectively. Negative cases were not associated with in situ neoplasia or metastasis, they were smaller (mean, 14 vs 39 mm), showed less histological diversity (2.4 vs 4.0 types of tissues on average) compared to positive cases.

Conclusion

Our study provides further evidence that prepubertal-type (type I) teratomas may appear in adult testes, thus teratomas in adults may be either benign (type I) or malignant (type II). IMP3 expression may aid the distinction between type I and type II teratomas of the postpubertal testis even when GCNIS and 12p status cannot be assessed.

Electronic supplementary material

The online version of this article (10.1007/s00428-020-02771-2) contains supplementary material, which is available to authorized users.

Testicular germ cell tumors (TGCTs) in neonates and infants

Dr. Louis Dehner has contributed significantly to our understanding of testicular germ cell tumors in children. This review article considers the molecular biology, clinical attributes, pathologic findings, and prognosis of those lesions.

The 2016 WHO Classification of Tumours of the Urinary System and Male Genital Organs-Part A: Renal, Penile, and Testicular Tumours

The fourth edition of the World Health Organization (WHO) classification of urogenital tumours (WHO "blue book"), published in 2016, contains significant revisions. These revisions were performed after consideration by a large international group of pathologists with special expertise in this area. A subgroup of these persons met at the WHO Consensus Conference in Zurich, Switzerland, in 2015 to finalize the revisions. This review summarizes the most significant differences between the newly published classification and the prior version for renal, penile, and testicular tumours. Newly recognized epithelial renal tumours are hereditary leiomyomatosis and renal cell carcinoma (RCC) syndrome-associated RCC, succinate dehydrogenase-deficient RCC, tubulocystic RCC, acquired cystic disease-associated RCC, and clear cell papillary RCC. The WHO/International Society of Urological Pathology renal tumour grading system was recommended, and the definition of renal papillary adenoma was modified. The new WHO classification of penile squamous cell carcinomas is based on the presence of human papillomavirus and defines histologic subtypes accordingly. Germ cell neoplasia in situ (GCNIS) of the testis is the WHO-recommended term for precursor lesions of invasive germ cell tumours, and testicular germ cell tumours are now separated into two fundamentally different groups: those derived from GCNIS and those unrelated to GCNIS. Spermatocytic seminoma has been designated as a spermatocytic tumour and placed within the group of non-GCNIS-related tumours in the 2016 WHO classification.

PATIENT SUMMARY

The 2016 World Health Organization (WHO) classification contains new renal tumour entities. The classification of penile squamous cell carcinomas is based on the presence of human papillomavirus. Germ cell neoplasia in situ of the testis is the WHO-recommended term for precursor lesions of invasive germ cell tumours.

Overview of pediatric testicular tumors in Korea

Prepubertal testicular tumors are rare compared with postpubertal testicular tumors. The incidence of prepubertal testicular tumors peaks at 2 years of age, tapers off after 4 years of age, and then begins to rise again at puberty. Prepubertal and postpubertal testicular tumors show many differences, including the typical tumor histology, molecular biological differences, and the malignant potential of tumors at different ages. Pediatric testicular tumors are classified as benign or malignant on the basis of their clinical behavior and histologically are divided into germ cell and gonadal stromal (nongerm cell) tumors. Many histological and biological studies have further confirmed the distinct nature of prepubertal and postpubertal testicular tumors. These differences have led to various management strategies for prepubertal and postpubertal tumors. Because overall about 75% of prepubertal testicular tumors are benign, a testis-sparing approach is becoming more common in children. Orchiectomy and observation with very selective use of chemotherapy has become the standard approach when a malignant tumor is identified. Retroperitoneal lymph node dissection and radiation therapy play very limited roles.

Difficult differential diagnoses in testicular pathology

CONTEXT

Although relatively rare, testicular cancer is the most common solid organ malignancy in young men and remains a leading cause of cancer death in this population. Different types of testicular tumors are treated differently, with an overall very high cure rate with proper management. Pathologists must, therefore, be familiar with important diagnostic pitfalls in testicular pathology, particularly those that result in different treatments or prognoses.

OBJECTIVE

To summarize key diagnostic features and useful ancillary tools for the most frequently encountered problems in testicular tumor pathology.

DATA SOURCES

Current texts, PubMed (National Library of Medicine) articles, and archives at Indiana University School of Medicine and Beth Israel Deaconess Medical Center were all reviewed.

CONCLUSIONS

Problematic differential diagnoses include seminoma versus nonseminomatous germ cell tumors, germ cell tumors versus non-germ cell tumors, intratubular germ cell neoplasia versus atypical germ cells with maturation arrest, pseudolymphovascular invasion versus real lymphovascular invasion in germ cell tumors, and macroscopic Sertoli cell nodules versus Sertoli cell tumors. In almost all cases, awareness of the differential diagnostic possibilities based on routine light microscopic features permits application of either additional, directed observations or immunohistochemical studies that lead to an accurate diagnosis.

Testing testes: problems and recent advances in the diagnosis of testicular tumours and implications for treatment

The low incidence of testicular tumours and the fact that they show an extremely high diversity means that they may be poorly understood. Knowledge of the range of tumours and the differences in treatment available is essential for appropriate management. The advent of cisplatin chemotherapy and the exquisite sensitivity of seminoma to radiotherapy have resulted in excellent cure rates. Nevertheless, research has continued unabated, particularly to understand the molecular basis of germ cell tumours and why certain tumours are recalcitrant to treatment. This overview is an attempt to demystify areas of confusion and highlight areas of current interest in testicular pathology and oncology.

Benign and Malignant Neoplasms of the Testis and Paratesticular Tissue

Benign and malignant tumors of the testes and paratesticular tissues present an interesting spectrum of diagnostic entities often encountered in routine surgical pathology practice. Germ cell tumors are the most common tumors of the testes and, despite a rising incidence, have excellent prognosis because of their radiosensitivity and/or effective chemotherapeutic agents. The proper classification of these tumors aids in the choice of appropriate treatment options. This article reviews benign and malignant neoplastic entities of the testes and paratesticular tissues and illustrates the classic pathologic characteristics. The differential diagnosis, along with ancillary studies, clinical significance, and presentation are discussed also.

[Frozen section in urological oncology]

The indications of Frozen section diagnosis (FS) in surgery due to urologic neoplasia are quite specific, and this explains the fact that they amount to a mere 7.3% of the FSs performed in general hospitals. This also makes the knowledge of their usefulness necessary, and thus we are submitting the present review. Generally speaking, FS is not warranted to identify the nature of a tumoral mass, with the following exceptions: (1) Renal masses of a doubtf ul parenchymal origin, or in the urinary tract: (2) Intesticular neoplasias,when the possibility of a conservative treatment arises; (3) Determination of the presence of a prostate adenocarcinoma in an organ donor with high serum PSA; but even in these circumstances its need is widely controversial. Intraoperative determination of surgical margins is particularly useful in: (1) Partial nephrectomies (it may be limited to inspection after dyeing the margin with Indian ink--bed freezing is very seldom needed); (2) Urethral margins in women with total cystectomies and orthotopic substitution; (3) In partial penectomies (always studying the urethral margin and the cavernosal and spongIosal corpora margins). The study of the nodes is a widely debated issue, and except for those cases in which unexpectedly increased node size is found, systematic FS is indicated neither of the bladder nor of the prostate. The situation regarding penis carcinoma is different, as in the groups with intermediate and high risk of node metastasis, even though there is around 16%-18% of false negatives FS is recommended, particularly of radioisotope-marked sentinel nodes.

The most common, clinically significant misdiagnoses in testicular tumor pathology, and how to avoid them

Testicular tumors are both increasing in frequency and disproportionately occur in young men; furthermore, different forms of neoplasm require different treatments. These considerations make the accurate diagnosis of testicular tumors especially important. Many of the critical distinctions involve the differentiation of seminoma from one or more potential mimics because seminoma is not only the most common testicular neoplasm but it is also the only malignant testicular tumor that is commonly treated with radiation, which is ineffective in other malignancies of the testis. For the most part, accurate diagnosis can be achieved by careful light microscopic evaluation, although appropriate immunostains can provide diagnostic assistance if doubt persists. This article discusses a number of clinically important differential diagnoses in the testis that are common sources of misinterpretations. These include: seminoma versus embryonal carcinoma, seminoma versus yolk sac tumor, seminoma versus Sertoli cell tumor, seminoma with syncytiotrophoblast cells versus choriocarcinoma, granulomatous seminoma versus granulomatous orchitis, intertubular seminoma versus orchitis, lymphoma versus seminoma or embryonal carcinoma, dermoid cyst versus teratoma, scar versus regressed germ cell tumor, and "anaplastic" spermatocytic seminoma versus usual seminoma or embryonal carcinoma.

Paratesticular mucinous cystadenoma arising from an oviduct-like müllerian remnant: a case report and review of the literature

A mucinous cystadenoma of the paratestis arising from an unequivocal oviduct-like structure in an 18-year-old man is reported. Mucinous cystadenomas of the testis and paratestis are extremely rare benign tumors of controversial origin. The diagnosis may be challenging and is of clinical importance because these lesions may mimic a teratoma, and teratomas in postpubertal males carry a malignant potential regardless of the degree of maturation. A few case reports and reviews of testicular and paratesticular mucinous neoplasms resembling ovarian tumors have suggested the possibility of a müllerian origin of these tumors. However, no histologic evidence has been found to support such a histogenesis. The current case demonstrates a clear transition from müllerian-type tubal epithelium to intestinal-type mucinous epithelium. This finding, in conjunction with immunophenotypic studies, strongly supports a derivation from a paratesticular müllerian remnant. To our knowledge this represents the first substantial evidence that, in at least some cases, mucinous cystadenomas of the testis and paratestis are of müllerian derivation.

Case series: Adult testicular dermoid tumours – mature teratoma or pre-pubertal teratoma?

Adult testicular dermoid tumours are rare tumours with no reported potential for recurrent or metastatic spread. Despite this they are currently classified as mature teratoma and managed as if they have equivalent malignant potential. This report describes two cases of adult mature teratoma of dermoid type and questions the classification and pathogenesis of this disease. In one of the cases there was a clear history of a testicular lump arising pre-pubertally, raising the possibility that some adult dermoid tumours may in fact be pre-pubertal teratomas that have persisted into adulthood. Classification as a mature teratoma carries with it a follow-up regimen that includes numerous radiological investigations with their attendant radiation exposure. A positive histological diagnosis and separate classification of adult dermoid tumours would allay clinical fears of recurrence and metastasis and negate the need for repeated radiological investigations.

Interphase fluorescence in situ hybridization analysis of chromosome 12p abnormalities is useful for distinguishing epidermoid cysts of the testis from pure mature teratoma

PURPOSE

The distinction of epidermoid cyst of the testis from teratoma is of critical importance because the former is benign and the latter is a malignant tumor that may have associated metastasis of either teratomatous or non-teratomatous germ cell tumor types. Chromosome 12p abnormalities are seen in the vast majority of testicular germ cell tumors of adults and are present in all histologic subtypes. In this study, we investigated the clinical utility of interphase fluorescence in situ hybridization (FISH) analysis of chromosome 12p abnormalities for distinguishing epidermoid cysts of the testis from pure mature teratoma.

EXPERIMENTAL DESIGN

Sixteen testicular epidermoid cysts and 17 testicular teratomas were investigated for isochromosome 12p [i(12p)] and 12p overrepresentation using interphase FISH analysis.

RESULTS

Neither i(12p) nor 12p overrepresentation were observed in 16 epidermoid cyst cases, whereas i(12p) was detected in 76% of teratomas and 12p overrepresentation was identified in 29% of teratomas. Overall, 88% of testicular teratomas had chromosome 12p abnormalities.

CONCLUSIONS

FISH identification of i(12p) and/or 12p overrepresentation in routinely processed surgical specimens is a useful ancillary diagnostic tool in distinguishing testicular epidermoid cysts from teratoma.

Analysis of ovarian teratomas for isochromosome 12p: evidence supporting a dual histogenetic pathway for teratomatous elements

Teratomas are the most common germ cell tumor (GCT) of the ovary and include several types with a range of clinical behavior. As in testicular teratomas, they may be benign, malignant or a component of a mixed GCT. In the testis, data support separate pathogeneses for prepubertal and postpubertal teratomas, with derivation of the former from a nontransformed germ cell and the latter from differentiation of a nonteratomatous, malignant GCT. The absence of cytogenetic abnormalities (including isochromosome 12p (i(12p)) in mature ovarian teratomas suggests that they may be analogous to prepubertal testicular teratomas, but there are no data regarding genetic changes in the teratomatous components of ovarian mixed GCTs. We therefore studied the teratomatous components of six mixed GCTs of the ovary using fluorescence in situ hybridization (FISH) for i(12p). Six mixed GCTs of the ovary occurred in patients 4-33 years of age; all had teratomatous and yolk sac tumor components and three also contained foci of embryonal carcinoma. Using FISH with 12p telomeric and 12 centromeric probes, five of six (83%) cases had detectable i(12p) in their nonteratomatous components, and four of six (66%) in the teratomatous component. One of the two cases without demonstrable i(12p) in the teratomatous portion of the mixed GCT also did not have identifiable 12p abnormalities in other elements of the mixed GCT. By comparison, five pure, mature ovarian teratomas and three pure, immature ovarian teratomas showed no evidence of either i(12p) or other forms of 12p amplification. These findings support that teratoma in mixed ovarian GCTs has a different pathogenesis compared to pure teratoma of the ovary. Furthermore, the findings of i(12p) in both the teratomatous and nonteratomatous components of ovarian mixed GCTs supports that the teratoma derives from other components, similar to the situation in the testis.

Sparing surgery for an epiderom cyst of the testis: a case report and literature review

Epidermoid cyst of the testis is relatively rare and accounts for less than 1% of all testicular neoplasms. This condition usually occurs in young men and it is mostly detected by self-examination or routine physical examination. The case of a 27-year-old male with an epidermoid cyst of the testis is discussed. The diagnosis was based on ultrasonography and management was with testicular-sparing surgery. At 2-year follow-up, the patient had had no relapse or metastasis. In epidermoid cysts of the testis, high-frequency ultrasonography is a reliable diagnostic imaging method. Organ-preserving surgery is recommended in the management of these lesions.

Germ cell tumors of the gonads: a selective review emphasizing problems in differential diagnosis, newly appreciated, and controversial issues

Gonadal germ cell tumors continue to be the cause of diverse, diagnostically challenging issues for the pathologist, and their correct resolution often has major important therapeutic and prognostic implications. They are academically interesting because of the biological diversity exhibited in the two gonads and variation in frequency of certain neoplasms. The most dramatic examples of the latter are the frequency of dermoid cyst in the ovary compared to the testis and the reverse pertaining to embryonal carcinoma. Within the teratoma group, there is strong evidence that ovarian and prepubertal testicular teratomas are derived from benign germ cells, a pathogenesis that likely applies also to the rare dermoid cysts and uncommon epidermoid cysts of the testis. In contrast, postpubertal testicular teratomas derive from malignant germ cells, specifically representing differentiation within a preexistent nonteratomatous cancer. As expected, given the foregoing, teratomas in boys are clinically benign, whereas in postpubertal males they are malignant, independent of their degree of immaturity. On the other hand, immaturity is an important finding in ovarian teratomas, irrespective of age, although its significance in children has recently been challenged. It is usually recognized on the basis of embryonic-appearing neuroepithelium, which shows mitotic activity and apoptosis in contrast to differentiated neuroepithelial tissues, which may occur in mature ovarian teratomas. Rarely it is based on the presence of cellular, mitotically active glial tissue. Fetal-type tissues alone are not sufficient for a diagnosis of immature teratoma. Further differences between the teratomatous tumors in the two gonads are the relative frequency of monodermal teratomas in the ovary in contrast to the testis, where only one subset, carcinoids, is seen with any frequency. When uncommon somatic-type malignancies (usually squamous cell carcinoma) occur in mature cystic teratomas of the ovary, this is a de novo form of malignant transformation; similar tumors in the testis, a very rare event, represent overgrowth of teratomatous elements that originated from malignant, nonteratomatous germ cell tumors and, therefore, had previously undergone malignant transformation. Germinomas may have several unusual features in each gonad; these include microcystic arrangements that suggest yolk sac tumor, tubular patterns that mimic Sertoli cell tumor, apparent increased cytological atypia that causes concern for embryonal carcinoma, and prominent syncytiotrophoblast giant cells that suggest choriocarcinoma. Awareness of these variants, good technical preparations, the retained typical cytological features of germinoma cells, and the judicious use of tailored panels of immunohistochemical stains resolve these dilemmas in virtually all instances. Two aspects of germinomas are unique to the testis. Firstly, intertubular growth of small seminomas may cause them to be overlooked. Secondly, the distinctive spermatocytic seminoma occurs only in the testis. A newly recognized aspect of this tumor is the propensity for some to be relatively monomorphic, making them apt to be mistaken for usual seminoma or embryonal carcinoma, although the characteristic polymorphic appearance in some foci, absence of intratubular germ cell neoplasia, unclassified type, and immunohistochemical stains should prevent this error. Cytoplasmic membrane immunoreactivity for placental alkaline phosphatase and CD117, with usual negativity for AE1/AE3 cytokeratins, is helpful in the diagnosis of germinoma. The recently described marker, OCT3/4, a nuclear transcription factor, is especially helpful in the differential of germinoma and embryonal carcinoma with other neoplasms. Yolk sac tumor continues to be confused occasionally with clear cell carcinoma of the ovary. Glandular ('endometrioid-like') yolk sac tumors mimic endometrioid carcinomas; predominant or pure hepatoid yolk sac tumors cause concern for metastatic hepatocellular carcinoma or, in the ovary, primary hepatoid carcinoma, and solid patterns, especially in limited samplings, may be misinterpreted as germinoma. The usually younger age of patients with yolk sac tumors helps with the differential considerations with the nongerm cell tumors, as do other clinical and microscopic features and selected immunohistochemical stains. Choriocarcinoma is rare in both gonads, and those in the ovary must be distinguished from metastatic tumors of placental origin. Syncytiotrophoblast cells alone, admixed with other forms of germ cell tumor, still are confused with choriocarcinoma, but this phenomenon, which is much more frequent than choriocarcinoma, lacks the plexiform arrangement of different trophoblast cell types that typifies the latter. Mixed germ cell tumors (which may show almost any combination of components) are common in the testis but rare in the ovary. A separately categorized, rare form of mixed germ cell tumor seen in both gonads is the polyembryoma. It is perhaps the most photogenic of all gonadal germ cell tumors and is also intriguing because of its distinctive, organized arrangement of yolk sac tumor and embryonal carcinoma elements and recapitulation of very early embryonic development, even to the extent of having in its fundamental unit, the embryoid body, a miniature yolk sac, and amniotic cavity. These tumors, which are constituted by innumerable embryoid bodies, almost always contain teratomatous glands in minor amounts, and one way of viewing the polyembryoma is to consider it the most immature form of teratoma. Embryoid bodies are also common as a minor component of many mixed germ cell tumors, particularly in the testis, and the diffuse embryoma is another variant that has a particular arrangement of yolk sac tumor and embryonal carcinoma elements. Regression of gonadal germ cell tumors is a phenomenon restricted to the testis, for unknown reasons. These so-called 'burnt-out' germ cell tumors can be recognized by a distinctive constellation of findings, including sometimes minor foci of residual recognizable germ cell neoplasia, a well-defined zone of scarring (often having residual ghost tubules), associated lymphoplasmacytic infiltrate, intratubular calcification and, in about 50%, of in situ germ cell neoplasia.

Intraoperative Frozen Section Diagnosis in Urological Oncology

The intraoperative frozen sections are indicated if the pathological findings change the surgical procedure. In urological oncology is not recommended, as a general attitude, in the tumor diagnosis/staging during the surgery. The assessment of the surgical margins is recommended in partial surgical resections but the literature discourages its systematic use in the radical surgical resections. The assessment of the lymph nodes is specially indicated in the penile cancer with intermediate or high risk and non-palpable nodes, and is debated its utility in non-palpable lymph nodes of cystectomies and prostatectomies.

PREPUBERTAL TESTIS TUMORS: ACTUAL PREVALENCE RATE OF HISTOLOGICAL TYPES

PURPOSE

Tumor registries, urological textbooks and literature surveys all assert that yolk sac tumors are the most common primary testicular tumors in boys 12 years and younger. In contrast, several individual institutions have reported that benign tumors are more common than malignant tumors. To clarify these discordant findings, we surveyed the primary pathology records from 4 major pediatric centers.

MATERIALS AND METHODS

The pathology records of the contributing centers were culled for primary testicular masses in boys 12 years and younger. Older boys and those with either paratesticular tumors or leukemia were excluded. The prevalence of each histological subtype was calculated from the pooled cases.

RESULTS

A total of 98 patients met our criteria. Only 15% had yolk sac tumors. Teratomas comprised 48% of the tumors (mature 44%, immature 4%). Epidermoid cysts were found in another 14% of patients. Gonadal stromal cell tumors represented 13% of the total, divided among granulosa cell (5%), Leydig cell (4%), Sertoli cell (3%) and mixed gonadal stromal cell (1%). Other pathology, including cystic dysplasia (2), lymphoma (4), inflammatory pseudotumor (1) and gonadoblastoma (2), made up 9% of the total number of cases.

CONCLUSIONS

We found that benign lesions represent the majority of primary testis tumors (74%), with the most common histological type being teratoma (48%). The reported high prevalence rates of prepubertal yolk sac tumors probably results from a reporting bias, since benign tumors are less likely to be submitted to tumor registries. Therefore, the primary operative approach to the majority of testis tumors in boys 12 years and younger should entail testis sparing surgery. Orchiectomy should be reserved for histologically confirmed malignancy based on increased preoperative alpha-fetoprotein and/or frozen section analysis of the tumor.

Epidermoid cyst in a solitary testis: A case for non-surgical management

This is a case report of a 71-year-old man who presented with an incidental finding of a mass in a solitary right testis. A scrotal ultrasound scan showed the typical features of a testicular epidermoid cyst. Tumour markers were not elevated and the patient was managed non-operatively. On reviewing the literature, we found no previous report on the non-operative management of testicular epidermoid cysts

Pediatric testicular tumors: contemporary incidence and efficacy of testicular preserving surgery

PURPOSE

Testicular tumors in the pediatric population are fundamentally distinct from their adult counterparts. We reviewed a contemporary single series from a large pediatric health science center. We also examined our experience with testis conserving surgery and then used it to develop a preoperative management algorithm.

MATERIALS AND METHODS

A retrospective review was performed of all testicular tumors at a single institution from 1984 to 2002. Data were compiled using the American Academy of Pediatrics testis tumor registry data collection form. We further examined partial orchiectomies for indications and outcomes with respect to cancer control and testicular viability.

RESULTS

A total of 51 primary testicular lesions were identified. Patient age was prenatal to 16 years with a scrotal mass the most common presentation (81%). Mature teratoma, rhabdomyosarcoma, epidermoid cyst, yolk sac and germ cell tumors accounted for 43%, 26%, 10%, 8% and 6% of cases, respectively. This distribution was markedly different from the last reported American Academy of Pediatrics data base. Organ preserving surgery was planned and achieved in 13 cases. All surgeries were successful with respect to cancer control and testicular preservation.

CONCLUSIONS

We believe that the higher incidence of teratoma is more representative of this population and yolk sac tumor is a minority diagnosis. The single institution review eliminates the interinstitutional referral heterogeneity that may have skewed larger data bases. Furthermore, the concept of testicular preserving surgery becomes an attractive option since we present its safety and efficacy. The management algorithm should facilitate the preoperative decision to perform less radical surgery and help preserve testicular tissue.

Identical allelic losses in mature teratoma and other histologic components of malignant mixed germ cell tumors of the testis

Teratomas of the testis in post-pubertal patients are histologically diverse tumors that often coexist with other types of germ cell tumors. Using laser capture microdissection and loss of heterozygosity analysis, we investigated the clonality of mature teratoma and its relationship to other components of malignant mixed germ cell tumors to gain potential insight into the histogenetic relationship of teratoma with other germ cell tumor components. All 16 patients had mature teratoma as one component of their mixed germ cell tumors. The other histological subtypes included immature teratoma, seminoma, embryonal carcinoma, yolk sac tumor, and choriocarcinoma. Laser-assisted microdissection was performed on the formalin-fixed, paraffin-embedded tissue. Polymerase chain reaction was used to amplify genomic DNA at specific loci on chromosome 1p36.2 (D1S508), 2q22-32 (D2S156), 9p21-22 (D9S162), 11p13 (D11S903), 12q22-23 (D12S1051), and 18q21 (D18S46). Fourteen of 16 (88%) cases showed allelic loss in one or more components of the mixed germ cell tumors. Fourteen of 16 mature teratomas showed allelic loss in at least one of six microsatellite polymorphic markers analyzed. The frequency of allelic loss in mature teratoma was 50% (7 of 14) with D1S508, 33% (5 of 15) with D2S156, 58% (7 of 12) with D9S162, 43% (6 of 14) with D11S903, 20% (3 of 15) with D12S1051, and 33% (5 of 15) with D18S46. Completely concordant allelic loss patterns between mature teratoma and all of the other germ cell tumor components were seen in 10 of 14 tumors in which mature teratoma showed loss of heterozygosity. Our data support the common clonal origin of mature teratoma with other components of malignant mixed germ cell tumors of the testis.

Gonadal teratomas: a review and speculation

Teratomas of the ovary and testis are confusing because, despite histologic similarities, they exhibit different biologic behaviors, depending mostly on the site of occurrence and the age of the patient. Thus, most ovarian teratomas are benign, and most testicular teratomas are malignant, with the exception of those occurring in children. These general statements, however, do not hold true for ovarian teratomas that are "immature" or exhibit "malignant transformation" and for dermoid and epidermoid cysts of the testis, categories of ovarian and testicular teratomas that are malignant and benign, respectively. This review concentrates on some of the "newer" observations concerning these interesting and confusing neoplasms, including diagnostically deceptive patterns. It is the author's opinion that much of the confusion regarding gonadal teratomas can be clarified by the concept that the usual ovarian teratoma derives from a benign germ cell in a parthenogenetic-like fashion, whereas the typical postpubertal testicular example derives from a malignant germ cell, mostly after evolution of that originally malignant cell to an invasive germ cell tumor (ie, embryonal carcinoma, yolk sac tumor, etc). The postpubertal testicular teratomas can therefore be thought of as an end-stage pattern of differentiation of a malignant germ cell tumor. The pediatric testicular teratomas, as well as dermoid and epidermoid cysts of the testis, however, must derive from benign germ cells, in a fashion similar to most ovarian teratomas. The teratomatous components of mixed germ cell tumors of the ovary, on the other hand, likely have a pathogenesis similar to that of postpubertal testicular teratomas.

Primary mucinous tumors of the testis and paratestis: a report of nine cases

Ovarian-type surface epithelial tumors are rare in the testis and paratestis, with most reported examples being serous. There is little information on mucinous tumors, nine of which are described in this report, applying criteria and terminology used in the ovary. The patients were 44-69 years of age (median 64 years) and presented with masses in the testis (four) or paratestis (five). Eight tumors were cystic (median size, 3.5 cm) and contained gelatinous material; one (a paratesticular carcinoma) appeared as thickening of the tunica vaginalis. Two were classified as mucinous cystadenomas (both paratesticular), six as purely or predominantly borderline tumors (four, testis; two, paratestis; one had intraepithelial carcinoma and one microinvasive carcinoma) and one (paratestis) as mucinous carcinoma. The cystadenomas were composed of endocervical-like cells, but intestinal-like cells typified the borderline tumors and carcinomas. Cyst rupture with mucin dissection into the stroma, inflammation, and dystrophic calcification with ossification were common. No tumor was associated with intratubular germ cell neoplasia, unclassified type or with teratomatous elements. One patient with carcinoma died shortly after presentation with peritoneal spread; autopsy disclosed no other potential primary site. The follow-up (1.8-12 years) in all other cases was uneventful. Mucinous tumors of the testis and paratestis resemble their ovarian counterparts, exhibiting the same morphologic spectrum, from benign to borderline to malignant, and having both endocervical-like and intestinal features. These tumors may derive from mesothelium by the process of mullerian neometaplasia, from mullerian remnants or from the mucinous epithelium of a teratoma. The older age of the patients, lack of nonmucinous elements, and absence of intratubular germ cell neoplasia, unclassified type suggest that, if of teratomatous origin, the teratoma is different from the usual type. Clinical features are important to exclude metastasis, particularly in cases of carcinoma and, to a lesser extent, in tumors of borderline type.

Mucinous cystadenoma of the testis

A 35-year-old man complained of a painless enlargement of the right testis. Imaging diagnostic procedures demonstrated a multiloculated cystic tumor, 9 cm in maximal diameter, in the right testis with hydrocele. Orchidectomy specimen showed that the tumor was confined within the testis and separated from the epididymis. The locules of the tumor were lined by single-layered columnar epithelium, intermingled with MUC2 immunopositive goblet and chromogranin-A immunopositive neuroendocrine cells, exhibiting intestinal differentiation. No ciliated cell, teratomatous element or intratubular germ cell neoplasia were seen. Channels of rete testis were compressed peripherally by the tumor but there was no connection with the tumor locules. The tumor was diagnosed as mucinous cystadenoma of the testis. This seems to be the first published case of benign mucinous cystadenoma occurring within the testis. This intratesticular tumor with intestinal differentiation may represent a benign monodermal teratoma.

Dermoid cyst of the testis: a study of five postpubertal cases, including a pilomatrixoma-like variant, with evidence supporting its separate classification from mature testicular teratoma

It is controversial if the rare dermoid cyst of the testis should be classified as a variant of mature teratoma or separately. The spectrum of findings is also ill defined, as is the relationship of dermoid cyst to intratubular germ cell neoplasia of the unclassified type (IGCNU). This study therefore reports the findings in five testicular dermoid cysts that occurred in five patients, 17-42 years of age, who presented with testicular masses. Four lesions consisted of a keratin-filled cyst with a thickened wall, whereas one had islands of "shadow" squamous epithelial cells with superimposed calcification and ossification (pilomatrixoma-like variant). Hair was identified grossly in two cases. On microscopic examination, four tumors had hair follicles with sebaceous glands showing a typical, cutaneous-type orientation to an epidermal surface, although no hair shafts were present in two. In addition, the fibrous wall contained smooth muscle bundles (all tumors) and eccrine or apocrine sweat glands (4 tumors). In some cases there were also glands lined by ciliated epithelium (4 tumors, including the pilomatrixoma-like variant), intestinal mucosa (1 tumor), and bone (2 tumors). There was no cytologic atypia or apparent mitotic activity, and no case had IGCNU in the seminiferous tubules. All patients were clinical stage I and were treated by orchiectomy without adjuvant therapy. All were well on follow-up from 1.5 to 9.5 years later. This study supports that dermoid cyst may have noncutaneous teratomatous elements and that an important criterion for its diagnosis is the absence of IGCNU. It also supports that it should be categorized separately from mature testicular teratoma because of the malignant nature of the latter in postpubertal patients. These observations suggest that there are at least two pathways for testicular teratomas in postpubertal patients: the more common being through IGCNU by differentiation from an invasive malignant germ cell tumor and the less common one, taken by dermoid cyst, by direct transformation from a nonmalignant germ cell.

Testis-sparing surgery for benign testicular tumors in children

PURPOSE

In this retrospective survey we identify preoperative and intraoperative criteria of nonmalignancy and analyze the result of conservative treatment of a testicular mass.

MATERIALS AND METHODS

A total of 22 surgeons responded to a questionnaire concerning lesions treated during the last 15 years in children between 0 and 15 years old. By definition alpha fetoprotein and beta human chorionic gonadotropin are within the normal limits at this age. The results were evaluated regarding evolution, growth of the preserved testis and local or distant recurrences.

RESULTS

Benign tumor of the testis (83 cases) represented 48% of all cases. Orchiectomy was performed in 27 cases and conservative treatment in 56. The final histopathological diagnosis was benign germinal tumor in 48 cases, cysts in 18, gonadal stromal tumor in 13 and rare lesions (lipoma, hemangioma) in 4. No definitive clinical criteria of nonmalignancy were identified but some symptoms were suggestive of nonmalignancy. Ultrasound results were more conclusive and provided the diagnosis of teratoma, epidermoid cyst and particularly simple cyst. The conservative treatment performed 56 times was a simple biopsy in 2 children with bilateral lesions and enucleation in 52. Enucleation was performed in 43% of cases using a pedicle clamp and in 50% with frozen section. The frozen section was changed in 12 cases due to therapeutic decision for preservation (10) and orchiectomy (2). There were no contradictions between the definitive histopathological examination and frozen section. Secondary orchiectomy was performed for neonatal granular tumor. Average followup in 56 cases of conservative treatment was 4.8 years (range 6 months to 15 years). Neither secondary testicular atrophy nor any local or distant recurrence was recorded.

CONCLUSIONS

A testicular tumor in children has a 50% chance of being benign. Treatment selection according to some clinical, biological, radiological and frozen section findings should allow us to decide on testis-sparing surgery without additional oncological risk, and with an aesthetic, psychological and functional benefit.

Diagnosis and management of teratomas and epidermoid cysts

One can strongly suspect a benign lesion in a prepubertal child on the basis of preoperative sonographic, biochemical, and clinical evaluation; however, when considering a testis-sparing enucleation, the definitive diagnosis must be established by pathologic frozen section of the tumor. The high incidence of benign testicular lesions in the prepubertal patient, the absence of associated carcinoma in situ in prepubertal germ cell tumors, and the universally benign behavior of the specific tumors described in this article are supportive evidence for testis-sparing surgery versus orchiectomy, for these benign lesions.

Testis sparing surgery for epidermoid cyst of the testis: a case report

A rare tumour of a prepubertal child, an epidermoid cyst, was excised with testicular preservation. Childhood testicular tumours are usually benign. Although epidermoid cysts of the testis may have teratomatous component, testicular teratomas are generally benign in the prepubertal child. For these reasons testis sparing surgery seems applicable in childhood epidermoid cysts.

Epidemiological features of testicular teratoma in a prepubertal population

PURPOSE

Prepubertal teratomas of the testis are rare benign tumors. Knowledge of the epidemiology of testicular teratomas and associated alpha-fetoprotein (AFP) levels could assist in planning treatment for prepubertal patients suspected of having teratoma of the testis.

MATERIALS AND METHODS

We evaluated data on testicular teratoma from the Prepubertal Testis Tumor Registry of the Section on Urology of the American Academy of Pediatrics.

RESULTS

Median patient age at presentation was 13 months. Teratomas occurred equally in the right and left testes. Most patients presented with a scrotal mass. Preoperative AFP levels were elevated in 20 of the 34 patients and postoperative levels were elevated in 9 of 10. Most patients were treated with radical orchiectomy and no metastatic disease was reported.

CONCLUSIONS

Data in the registry confirm the benign nature of this tumor. Normal AFP levels should not be expected in infants with teratoma.