Molecular evidence supporting the neoplastic nature of some epidermoid cysts of the testis

Germ cell neoplasms of the testis: Update for 2022

Germ cell neoplasia in situ (GCNIS) is the precursor of both seminomatous and non-seminomatous germ cell tumors. It consists of distended tubules that may have either intratubular seminoma or intratubular embryonal carcinoma cells. Many invasive non-seminomatous tumors contain a mixture of tumor types, which are reviewed here. Morphology, aided by a panel of immunostains, can determine the presence and percent of embryonal carcinoma, yolk sac tumor, choriocarcinoma, or teratoma in such tumors. Use of immunostains, required for diagnosis in perhaps 25% of testicular neoplasms, is reviewed. Changes of classification in the AJCC (8^th edition) in 2016 are discussed, including the partitioning of two tumor types: the central role of chromosome 12p amplification allows both teratoma and yolk sac tumor to be divided into prepubertal types (lacking amplification) and post-pubertal types. Occasionally, sex cord-stromal tumors, hematolymphoid tumors, or epididymal adenomatoid tumors enter the differential diagnosis of germ cell neoplasms.

Unusual presentation of epidermoid cyst from testis in an aging male

Epidermoid cysts, which constitute 1% of all testicular tumors, are considered to be benign even though histogenesis is not clear. Patients usually suffer from painless scrotal mass or this mass is realized during the routine physical examination. Hematospermia may be a finding for both benign and malignant testicular tumors. Many authors advocate the testicular sparing surgery in the treatment but epidermoid cysts are usually treated with radical inguinal orchiectomy, because of the difficulties in the diagnosis, concurrence of the malignant tumors, and the debate on the histogenesis.

Laser-assisted microdissection in translational research: theory, technical considerations, and future applications

Molecular profiling already exerts a profound influence on biomedical research and disease management. Microdissection technologies contribute to the molecular profiling of diseases, enabling investigators to probe genetic characteristics and dissect functional physiology within specific cell populations. Laser-capture microdissection (LCM), in particular, permits collation of genetic, epigenetic, and gene expression differences between normal, premalignant, and malignant cell populations. Its selectivity for specific cell populations promises to greatly improve the diagnosis and management of many human diseases. LCM has been extensively used in cancer research, contributing to the understanding of tumor biology by mutation detection, clonality analysis, epigenetic alteration assessment, gene expression profiling, proteomics, and metabolomics. In this review, we focus on LCM applications for DNA, RNA, and protein analysis in specific cell types and on commercially available LCM platforms. These analyses could clinically be used as aids to cancer diagnosis, clinical management, genomic profile studies, and targeted therapy. In this review, we also discuss the technical details of tissue preparation, analytical yields, tissue selection, and selected applications using LCM.

Intratesticular epidermoid cyst: a rare tumor

Testicular epidermoid cyst is extremely rare injury, which in recent studies has been regarded as a tumor. Some authors consider this lesion as a cystic monodermal teratoma, the histogenesis remains controversial. In this study we provide clinical and morphological characteristics of an epidermoid cyst in the left testicle in a 16 years old patient, where apparently a nodular lesion in the left testicle was detected.

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.

Clonal Origin of Metastatic Testicular Teratomas

PURPOSE

Testicular teratomas in adult patients are histologically diverse tumors that frequently coexist with other germ cell tumor (GCT) components. These mixed GCTs often metastasize to retroperitoneal lymph nodes where multiple GCT elements are frequently present in the same metastatic lesion. Neither the genetic relationships among the different components in metastatic lesions nor the relationships between primary and metastatic GCT components have been elucidated.

EXPERIMENTAL DESIGN

We examined metastases from 31 patients who underwent primary retroperitoneal lymph node dissection for metastatic testicular GCT. All patients had metastatic mature teratoma with one or more other GCT components. This study included a total of 72 metastatic GCT components and 16 primary GCT components from 31 patients. Genomic DNA samples from each component were prepared from formalin-fixed, paraffin-embedded tissue sections using laser-assisted microdissection. Loss of heterozygosity (LOH) assays for seven microsatellite polymorphic markers on chromosomes 1p36 (D1S1646), 9p21 (D9S171 and IFNA), 9q21 (D9S303), 13q22-q31 (D13S317), 18q22 (D18S543), and 18q21 (D18S60) were done to assess clonality.

RESULTS

Twenty-nine of 31 (94%) cases showed allelic loss in one or more components of the metastatic GCTs. Twenty-nine of 31 mature teratomas showed allelic loss in at least one of seven microsatellite polymorphic markers analyzed. The frequency of allelic loss in informative cases of metastatic mature teratoma was 27% (8 of 30) with D1S1646, 34% (10 of 29) with D9S171, 37% (10 of 27) with IFNA, 27% (8 of 30) with D9S303, 46% (13 of 28) with D13S317, 26% (7 of 27) with D18S543, and 36% (10 of 28) with D18S60. Completely concordant allelic loss patterns between the mature teratoma and all of the other metastatic GCT components were seen in 26 of 29 cases in which the mature teratoma component showed LOH. Nearly identical allelic loss patterns were seen in the three remaining cases. In six cases analyzed, LOH patterns of each metastatic component were compared with each GCT component of the primary testicular tumor. In all six cases, each primary and metastatic component showed an identical pattern of allelic loss.

CONCLUSION

Our data support the common clonal origin of metastatic mature teratomas with other components of metastatic testicular GCTs and with each component of the primary tumor.

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.

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

Molecular genetic evidence for different clonal origins of epithelial and stromal components of phyllodes tumor of the prostate

Phyllodes tumor of the prostate is a rare neoplasm, composed of epithelium-lined cysts and channels embedded in a variably cellular stroma. The pathogenetic relationship of the epithelium and stroma is unknown and whether each is a clonal neoplastic element is uncertain. We studied the clonality of phyllodes tumors from six patients who underwent either enucleation or transurethral resection as their initial treatment. This was followed by total prostatectomy in three of the patients. Laser-assisted microdissection was performed to extract epithelial and stromal components of phyllodes tumor from formalin-fixed, paraffin-embedded tissue. Polymerase chain reaction was used to amplify genomic DNA at specific loci on chromosome 7q31 (D7S522), 8p21.3-q11.1 (D8S133, D8S137), 8p22 (D8S261), 10q23 (D10S168, D10S571), 17p13 (TP53), 16q23.2 (D16S507), 12q11-12 (D12S264), 17q (D17S855), 18p11.22-p11 (D18S53), and 22q11.2 (D22S264). In each tumor, stroma and epithelium were analyzed separately. Gel electrophoresis with autoradiography was used to detect loss of heterozygosity. All tumors showed allelic loss in one or more loci of both the epithelial and stromal components. The frequency of allelic loss in the epithelial component was 2 of 5 (40%) at D7S522, 2 of 6 (33%) at D8S133, 1 of 5 (20%) at D8S137, 3 of 6 (50%) at D8S261, 4 of 4 (100%) at D10S168, 4 of 6 (67%) at TP53, 2 of 6 (33%) at D10S571, 6 of 6 (100%) at D16S507, 1 of 5 (20%) at D12S264, 1 of 6 (17%) at D17S855, 2 of 6 (33%) at D18S53, and 2 of 5 (40%) at D22S264. The frequency of allelic loss in the stromal component was 2 of 5 (40%) at D7S522, 1 of 6 (17%) at D8S133, 2 of 5 (40%) at D8S137, 3 of 6 (50%) at D8S261, 1 of 4 (25%) at D10S168, 3 of 6 (50%) at TP53, 2 of 6 (33%) at D10S571, 3 of 6 (50%) at D16S507, 1 of 5 (20%) at D12S264, 0 of 6 (0%) at D17S855, 1 of 6 (17%) at D18S53, and 0 of 5 (0%) at D22S264. The pattern of allelic loss is significantly different in both stroma and epithelium statistically; completely concordant allelic loss patterns were not seen in any tumor examined. Our data demonstrate that both epithelial and stromal components of phyllodes tumor of the prostate are clonal, supporting the hypothesis that both elements are neoplastic. While both epithelium and stroma are clonal proliferations, they appear to have different clonal origins.

Nephroblastoma Arising in a Germ Cell Tumor of Testicular Origin

We report a nephroblastoma arising in a germ cell tumor of testicular origin occurring in a 22-year-old man. Orchiectomy demonstrated a malignant mixed germ cell tumor composed of mature and immature teratoma with nephroblastoma and rhabdomyosarcoma. Following chemotherapy, the patient developed supraclavicular and retroperitoneal lymphadenopathy. Excision demonstrated metastatic teratoma at both sites. No recurrence was noted with 21 months of additional follow-up. Using tissue microdissection and loss of heterozygosity analysis, we investigated the clonality of the mature teratoma, immature teratoma, nephroblastoma, and rhabdomyosarcoma components of the primary tumor and of the metastatic mature teratoma at the two separate distant sites. Nine microsatellite polymorphic makers were used to examine the pattern of allelic loss in both primary and metastatic tumors. Loss of heterozygosity was found in 4 DNA loci, and the same pattern of allelic loss was demonstrated at all 4 loci in all of the different components of the primary tumor and the metastatic mature teratomas, supporting the germ cell tumor origin of the nephroblastoma component. Loss of heterozygosity on chromosome 17p13 (TP53) was detected in metastatic mature teratoma, but not in the primary tumor. Loss of heterozygosity was observed at 11p13, the locus of WT1 inactivation in patients genetically predisposed to nephroblastoma, and this loss may be an important genetic mechanism in nephroblastomatous differentiation of germ cell tumors. These data support a common clonal origin for nephroblastoma and the other germ cell tumor components.

Allelic Loss of the Active X Chromosome During Bladder Carcinogenesis

Context.—Previous studies have shown that loss of the X chromosome is involved in the carcinogenesis of certain human malignancies.

Objective.—To determine whether X-linked allelic losses occur during bladder tumorigenesis and whether such losses involve the active or the inactive X chromosome.

Design.—We analyzed the deletion status of the X-linked human androgen receptor gene locus in 6 female patients who underwent radical cystectomies for muscle-invasive urothelial carcinoma of the urinary bladder. Four patients had coexisting urothelial carcinoma in situ. Analysis for inactivation of the X chromosome was carried out in parallel.

Results.—Three cases were informative. Invasive tumor samples showed loss of heterozygosity involving the active allele at the androgen receptor locus in all 3 positive cases, whereas carcinoma in situ showed nonrandom X chromosome inactivation but not allelic deletion.

Conclusions.—Our data suggest that allelic loss of the activated X chromosome is involved in bladder carcinogenesis and cancer progression.