Mesothelioma of tunica vaginalis testis in a child

Molecular and Immunohistochemical Characterization of Mesothelioma of the Tunica Vaginalis

AIMS

Malignant mesothelioma (MM) of the tunica vaginalis (TV) is a rare and aggressive tumor, and the molecular features and staining profile with contemporary immunohistochemical (IHC) biomarkers are largely unexplored. We characterize the clinicopathologic, molecular, and IHC features of MM (N=13) and mesothelial neoplasms of uncertain malignant potential (MUMP) (N=4).

METHODS AND RESULTS

Targeted next-generation sequencing was performed on 7 MMs and 2 MUMPs. IHC was performed for MTAP, BAP1 and SOX6. 13 adenomatoid tumors were also assessed with SOX6. MM were epithelioid (7/13) or biphasic (6/13). In MM, NF2 (5/7; 71%), CDKN2A (3/7; 43%), and BAP1 (2/7; 29%) were most frequently altered. Non-recurrent driver events were identified in PTCH1 and TSC1. In contrast, none of these alterations were identified in MUMPs; however, one MUMP harbored a TRAF7 missense mutation. By IHC, loss of MTAP (2/12; 17%) and BAP1 (2/9; 22%) was infrequent in MM, whereas both were retained in the MUMPs. SOX6 was positive in 9/11 (82%) MMs, and negative in all MUMPs and adenomatoid tumors.

CONCLUSIONS

Testicular MM exhibit a similar mutational profile to those of the pleura/peritoneum; however, alterations in CDKN2A and BAP1 are less common. These findings suggest that although MTAP and BAP1 IHC are specific for MM, their sensitivity in testicular MMs appears lower. In addition, rare tumors may harbor targetable alterations in driver genes (PTCH1 and TSC1) that are unusual in MMs at other anatomic sites. SOX6 is sensitive for MM; accordingly, the presence of SOX6 expression argues against a benign neoplastic process.

Asbestos exposure and malignant mesothelioma of the tunica vaginalis testis: a systematic review and the experience of the Apulia (southern Italy) mesothelioma register

BACKGROUND

Malignant mesothelioma of the tunica vaginalis testis (MMTVT) is a rare disease with a poor prognosis. The diagnosis and management of these lesions are often difficult for pathologists, surgeons, oncologists and occupational physicians. A preoperative diagnosis of malignancy is rarely made, and there is no established effective therapy except orchidectomy.

METHODS

A systematic literature review was conducted among the articles published in the English literature on primary MMTVT. Moreover four cases from the Apulia mesothelioma register are reported here.

RESULTS

Two hundred eighty-nine cases of MMTVT have been reported from 1943 to 2018. Overall asbestos exposure has been investigated only for 58% of all cases reported in this review, while in 41.8% this data are not available. Noteworthy is the fact that in many reports there is not an anamnestic reconstruction of any asbestos exposure. A history of direct occupational, environmental or familial asbestos exposure is found in 27.6% of the cases. The four cases from the Apulia mesothelioma register are all with ascertained occupational exposure to asbestos.

CONCLUSIONS

The true incidence of asbestos exposure in MMTVT is underestimated because of insufficient information reported in older literature. To establish a broad consensus on the causal relationship between asbestos and MMTVT in the scientific community its necessary to analyze the same variables in the epidemiological studies. In general it should be recommended that a positive history of exposure to asbestos or to asbestos-containing materials are at risk for the development of a MMTVT and should be monitored.

Histologic analysis of the hernia sac: current practices based on a survey of IPEG members

INTRODUCTION

Inguinal hernia repair is one of the most common operations performed by pediatric surgeons. Although the practice of sending the hernia sac for histologic examination after routine hernia repair is common, the indications and practice patterns for this have not been evaluated. The objective of this survey was to determine practice patterns and indications for histologic analysis of the pediatric inguinal hernia sac.

MATERIALS AND METHODS

A 9-question online survey was sent to all members of the International Pediatric Endosurgery Group (IPEG). A Kruskal-Wallis test was used to determine whether practice patterns of sending the hernia sac for histologic evaluation were associated with respondent characteristics. The chi-squared test with Yates's correction was used where appropriate.

RESULTS

The survey was completed by 315 IPEG members, for a response rate of 54.4%. Hernia sacs were sent for histologic evaluation always by 23.9%, often by 5.1%, rarely by 17.5%, and never by 53.5%. The respondent characteristics were not associated with whether or not specimens were sent for histology review. Of the 128 who reported sending the inguinal hernia sac, the most common reasons were hospital/state requirements (47.6%), followed by routine practice (25.7%) and concern for missed pathology (24.2%).

CONCLUSIONS

The majority of IPEG respondents report never sending the inguinal hernia sac for histologic analysis. Of those that do, most are influenced by hospital/state requirements. The value of sending the hernia sac after routine inguinal hernia repair should be validated if it is to remain an institutional requirement.

Malignant mesothelioma of the tunica vaginalis testis: diagnostic studies and differential diagnosis

Malignant mesothelioma of the tunica vaginalis testis is an extremely rare tumor representing 0.3% to 5% of all malignant mesotheliomas. Gross examination of testicular mesotheliomas typically reveals tumor nodules studding the thickened tunica vaginalis and, in some cases, infiltrating the testicular parenchyma, leading to diagnostic challenges. Microscopically, the tumor is characterized by epithelioid cells arising from the tunica vaginalis with papillary, tubulopapillary, or solid architectural patterns. The papillae are usually lined by a single layer of cells with relatively bland cytologic features. An epithelial cell phenotype admixed with a sarcomatoid pattern has also been described in a few cases. Immunohistochemically, the tumor is usually positive for calretinin, Wilms tumor-1, epithelial membrane antigen, D2-40, thrombomodulin, cytokeratin 7, and cytokeratin 5/6. Electron microscopic studies reveal epithelial cells joined by tight junctions, forming lumina, and displaying long microvilli with length to width ratios often greater than 10. The most important differential diagnostic considerations include florid mesothelial hyperplasia, adenomatoid tumor, carcinoma of the rete testis, and serous papillary tumors. In addition, the various types of testicular germ cell tumors should be considered, including seminomas, embryonal carcinomas, and intratubular germ cell tumors, particularly in tumors with testicular parenchymal involvement. Pleomorphic sarcomas should also be considered, particularly when dealing with the biphasic variant. The prognosis for this entity is grave, with a median survival of 23 months. Aggressive therapy with radical orchiectomy remains the mainstay of treatment.

Paratesticular mesothelioma. Report of a case with comprehensive review of literature

Paratesticular mesotheliomas are rare tumors with 223 cases described so far. The sole plausible causative factor so far ascertained in the pathogenesis of these tumors is asbestos, which however is found in only around 30% to 40% of such cases. The age range of affected individuals is wide, mostly adults and the elderly, but also includes young people and children. The most common presenting symptom is either hydrocele of unknown origin or intrascrotal mass. When hydrocele is the presenting symptom, these tumors are often clinically overlooked and the diagnosis is delayed. Most paratesticular mesotheliomas arise in the tunica vaginalis, but primary tumors of the spermatic cord and epididymis are also on record. Tumors arising from the peritoneal mesothelium of a hernia sac are excluded from this group. The correct diagnosis is almost always made after histologic examination of the operative specimen. Immunohistochemistry and electron microscopy are always helpful and sometimes necessary tools for diagnosis. So far very few cases have been identified or suspected preoperatively on cytologic examination. Three clinicopathologic types of malignant mesotheliomas of the male genital tract are recognized: diffuse tubulo-papillary mesothelioma, well-differentiated papillary mesothelioma, and multicystic mesothelioma. The histologic subtypes are almost always pure epithelial or biphasic. The differential diagnosis is mainly with serous papillary tumors arising from Mullerian vestiges, but several diverse primary or secondary tumors also need to be considered. A clinicopathologic evaluation of a case of tunical diffuse mesothelioma in a 74-year-old male from the AMR Series is the starting point for this general review.

A rare case of malignant hydrocele in a young patient

Malignant mesotheliomas of the tunica vaginalis are extremely rare tumors, especially in young patients. We report a case of a 15-year old patient presenting with clinical signs of hydrocele. Preoperative ultrasound scanning revealed two papillary lesions. Initially, before mesothelioma was suspected, the patient was submitted to focal resection of the macroscopic lesions. Following diagnosis by histopathology, the patient was submitted to radical orchiectomy and hemiscrotectomy. The patient presents no signs of local or systemic recurrence at the time of writing. A review of the literature on the subject has been included.

Malignant mesothelioma of tunica vaginalis testis associated with long-lasting hydrocele: could hydrocele be an etiological factor?

A case of malign mesothelioma of tunica vaginalis testis in a 67 year old man with a 30 year history of hydrocele was reported. The diagnosis was made with an excisional biopsy performed in scrotal exploration and revealed epithelial type mesothelioma. High orchiectomy with hemiscrotectomy was performed. The patient had a local recurrence at the end of two years. As there were no distant metastasis only local excision was performed. In his sixth month after the second surgery he is still tumor free. Related literature reviewed.

Malignant mesothelioma of the tunica vaginalis testis: review of the literature and assessment of prognostic parameters

BACKGROUND

Only 73 cases of malignant mesothelioma of the tunica vaginalis testis have been reported in the last 30 years. Although these tumors were most often seen in patients between ages 55 and 75 years, 10% of the patients were younger than 25 years. Because prognostic parameters have not yet been reported, the authors present another case of a male age 14 years and a review of the available literature, which they conducted to determine prognostic parameters.

METHODS

The medical literature about malignant mesothelioma of the tunica vaginalis testis was reviewed. For the determination of prognostic parameters, a univariate and multivariate Cox regression model was used to assess the relevance of the patient's age, history of asbestos exposure, tumor histology, primary therapeutic approach, and presence of metastatic disease to survival.

RESULTS

Previous exposure to asbestos or asbestos-containing materials must be considered a risk factor for the development of malignant mesothelioma. The major difficulty in managing patients with malignant mesothelioma of the tunica vaginalis testis was determining an accurate preoperative diagnosis, which was reported in only two cases. Due to the lack of characteristic symptoms, 97.3% of the cases were diagnosed intraoperatively. Of patients who underwent local resection of the hydrocele wall, 35.7% experienced local tumor recurrence, as compared with 10.5% after scrotal orchiectomy and 11.5% after inguinal orchiectomy. Therefore, radical orchiectomy should be the first-line therapy. The median survival of the patients was 23 months, which decreased to 14 months in cases of recurrence. The overall recurrence rate (local and disseminated) was 52.5%. More than 60% of recurrences developed within the first 2 years of the follow-up. In some cases of disseminated mesothelioma, adjuvant chemotherapy or radiotherapy was given. Although reports on adjuvant treatments were limited, radiotherapy appeared to be more effective than chemotherapy. However, 37.9% died of disease progression. Assessment of prognostic parameters revealed a significant correlation of patient's age with survival (P < 0.01), with a better outcome for younger patients and a worse disease course for patients with primary disseminated disease (P < 0.05) in univariate analysis. A multivariate Cox regression model of prognostic parameters concerning survival did not yield statistically significant results.

CONCLUSIONS

Malignant mesotheliomas of the tunica vaginalis testis rarely occur, but the possibility should be considered for all age groups. Univariate analysis determined that a patient's age and the presence of primary disseminated disease were prognostic parameters related to survival. Due to the invasive potential of this disease and the risk of tumor recurrence, radical orchiectomy and close follow-up are strongly recommended.