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

Multisocietal Consensus on the Use of Cytoreductive Surgery and HIPEC for the Treatment of Diffuse Malignant Peritoneal Mesothelioma: A GRADE Approach for Evidence Evaluation and Recommendation

The Peritoneal Surface Oncology Group International (PSOGI) previously issued a recommendation endorsing cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for treating diffuse malignant peritoneal mesothelioma (DMPM). However, broader acceptance of this approach, particularly within some segments of medical oncology, remains limited. To address this, PSOGI initiated a multisociety consensus effort, involving multidisciplinary International Societies, to strengthen and expand the endorsement of CRS-HIPEC for DMPM. Using the GRADE ADOLOPMENT approach, the expert panel systematically reviewed existing guidelines and evaluated the available evidence to reinforce the recommendation. The panel unanimously recommended CRS-HIPEC for a carefully selected subset of DMPM patients, emphasizing that this approach offers the best potential for improved survival compared to systemic chemotherapy alone. Despite the very low certainty of evidence, a strong recommendation was issued, reflecting the panel's recognition of the life-threatening feature of DMPM and the limited efficacy of systemic chemotherapy. This consensus also highlights the importance of centralized and expert-driven care. The recommendation aligns with previous guidelines and underscores the critical need for broader acceptance of this treatment strategy in managing this rare and aggressive malignancy.

Malignant Para-Testicular Mesothelioma: A Rare Presentation in the Tunica Vaginalis of an Elderly Male With No Prior Asbestos Exposure

Malignant mesothelioma of the tunica vaginalis is an extremely rare and aggressive tumor that is frequently encountered in elderly patients. The diagnosis of malignant mesothelioma of the tunica vaginalis poses a diagnostic challenge due to its infrequency and nonspecific clinical presentation. Histopathological examination and immunohistochemical staining are essential in differentiating this tumor from other para-testicular masses and establishing a definitive diagnosis. Early detection and comprehensive treatment planning are crucial for improving the prognosis and overall outcomes for patients with this rare malignancy. We present a report of malignant mesothelioma of the tunica vaginalis in a 78-year-old male patient with no history of asbestos exposure who presented with a large infiltrative left para-testicular mass. Histopathological examination revealed a biphasic proliferation composed of epithelioid and spindle cells with infiltrative features, foci of necrosis, and increased mitotic figures. Immunohistochemical staining exhibited positive staining for WT1, D2-40, and calretinin, supporting the mesothelial origin of the tumor. Notably, BerEP4 staining was negative, arguing against carcinoma. Immunostaining for keratin 5 was positive, supporting the mesothelial differentiation. The Ki67 proliferation index was high. The differential diagnosis included adenomatoid tumors, germ cell tumors, and pleomorphic sarcoma. We aim to discuss the clinical presentation, diagnostic approach, and therapeutic approaches of this rare entity.

NF2: An underestimated player in cancer metabolic reprogramming and tumor immunity

Neurofibromatosis type 2 (NF2) is a tumor suppressor gene implicated in various tumors, including mesothelioma, schwannomas, and meningioma. As a member of the ezrin, radixin, and moesin (ERM) family of proteins, merlin, which is encoded by NF2, regulates diverse cellular events and signalling pathways, such as the Hippo, mTOR, RAS, and cGAS-STING pathways. However, the biological role of NF2 in tumorigenesis has not been fully elucidated. Furthermore, cross-cancer mutations may exert distinct biological effects on tumorigenesis and treatment response. In addition to the functional inactivation of NF2, the codeficiency of other genes, such as cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B), BRCA1-associated protein-1 (BAP1), and large tumor suppressor 2 (LATS2), results in unique tumor characteristics that should be considered in clinical treatment decisions. Notably, several recent studies have explored the metabolic and immunological features associated with NF2, offering potential insights into tumor biology and the development of innovative therapeutic strategies. In this review, we consolidate the current knowledge on NF2 and examine the potential connection between cancer metabolism and tumor immunity in merlin-deficient malignancies. This review may provide a deeper understanding of the biological roles of NF2 and guide possible therapeutic avenues.

A rare malignant mesothelioma of the tunica vaginalis testis: A case report

Malignant mesothelioma of the tunica vaginalis testis is a rare, highly invasive urogenital malignant tumor with no specific clinical manifestations. Reported cases of this disease are limited. Therefore, an early preoperative diagnosis is difficult. The current study presents a case of malignant mesothelioma of the tunica vaginalis testis and a literature review. A 52-year-old man was admitted to Xiaoshan Affiliated Hospital of Wenzhou Medical University (Hangzhou, China) in December 2022 and underwent radical resection of the right testicle and epididymis but did not undergo radiotherapy or chemotherapy. The patient was followed up for 5 months, and no recurrence or metastasis was found. The rarity of testicular mesothelioma poses a challenge to its etiology and diagnosis, which is rarely achieved preoperatively. Malignant mesothelioma of the testicular tunica vaginalis has a poor prognosis and is not sensitive to radiotherapy or chemotherapy, requiring close postoperative follow-up. This condition is rare in clinical practice; therefore, it needs to be reported to aid clinicians' decision-making regarding diagnosis and treatment.

Testicular/paratesticular mesothelial tumours: Uncommon histopathologic entities in a very complex anatomical site

Mesothelial tumours of the testicular/paratesticular region are uncommon, poorly characterised and difficult-to-diagnose lesions. They encompass entirely benign proliferations (adenomatoid tumour) and malignant, very aggressive tumours (mesothelioma) whose morphological features can be overlapping, highly variable and confounding. Moreover, testicular/paratesticular mesothelial tumours comprise relatively new entities with indolent behaviour (well-differentiated papillary mesothelial tumour) as well as tumours which cannot be correctly included in any of the aforementioned categories and whose classification is still controversial. The molecular profile of such tumours represents an open issue. In fact, despite the recent discoveries about the genomic landscape of mesothelial proliferations at other sites (pleura, peritoneum), testicular/paratesticular mesothelial tumours, and namely mesotheliomas, are too rare to be extensively studied on large case series and they could arguably hide relevant differences in their molecular background when compared to the more common pleural/peritoneal counterparts.The aim of this review is to provide a guide for the pathological assessment of testicular/paratesticular mesothelial tumours. Herein, we describe the most recent updates on this topic according to the latest (year 2022) World Health Organisation Classification of Urinary and Male Genital Tumours (5th edition) and current literature. The diagnostic criteria, the main differentials and the role of ancillary techniques in the diagnosis of mesothelial testicular/paratesticular tumours are discussed.

Benign Mesothelial Proliferations of the Tunica Vaginalis Testis

The correct diagnosis of mesothelial proliferations is a classic problem for pathologists, and one which has important clinical implications. A significant number of such cases appear associated with recurrent hydrocele, as an irritative/reactive response to this condition. The morphological spectrum of mesothelial lesions in this topography is broad, and a set of benign conditions may appear, sometimes with florid gross features and cytologic pseudo-atypia. Here, we present two different examples in which malignancy was initially considered in the differential diagnosis.

Chinese expert consensus on the diagnosis and treatment of malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a malignant tumor originating from the pleura, and its incidence has been increasing in recent years. Due to the insidious onset and strong local invasiveness of MPM, most patients are diagnosed in the late stage and early screening and treatment for high-risk populations are crucial. The treatment of MPM mainly includes surgery, chemotherapy, and radiotherapy. Immunotherapy and electric field therapy have also been applied, leading to further improvements in patient survival. The Mesothelioma Group of the Yangtze River Delta Lung Cancer Cooperation Group (East China LUng caNcer Group, ECLUNG; Youth Committee) developed a national consensus on the clinical diagnosis and treatment of MPM based on existing clinical research evidence and the opinions of national experts. This consensus aims to promote the homogenization and standardization of MPM diagnosis and treatment in China, covering epidemiology, diagnosis, treatment, and follow-up.

Malignant Mesothelioma of Tunica Vaginalis Testis: Update for 2022

Malignant mesothelioma of the testicular tunics is rare. About one third of cases are metastatic and carry a poor prognosis. This paper reviews the epidemiology, clinicopathologic features, treatment, and outcome of this entity.

Multimodal Management of Testicular Mesothelioma - A Retrospective Analysis From a Tertiary Cancer Care Centre

The main modality of management of paratesticular mesothelioma remains orchiectomy while the use of adjuvant chemotherapy has not yet been explored. We aim to analyse the outcome of the multimodal management protocol in testicular mesothelioma We conducted a retrospective analysis of patients registered and treated for testicular mesothelioma between 2009 and 2019 in an oncology tertiary care hospital. Patients presenting with nodal, metastatic disease were treated with adjuvant, palliative chemotherapy respectively and their response to treatment was periodically monitored. Eight patients (3 early, 1 nodal, 4 metastatic) with median age of 58 years was included in the study. Patients who had limited (early, nodal) disease (n = 4) had overall survival ranging from 20 to 140 months while metastatic disease (n = 4) had poor outcomes with overall survival ranging from 2 to 13 months. Surgery remains to be an important modality of therapy that improves the local control and overall outcomes and the quality of life even in patients with metastatic disease at the time of diagnosis. Adjuvant chemotherapy might play a role in effective management of locoregional disease. The performance status, the extent of disease at the time of presentation are the important prognostic factors in deciding the outcome of the disease management.

Diagnostic and Therapeutic Pathway in Diffuse Malignant Peritoneal Mesothelioma

Diffuse malignant peritoneal mesothelioma (DMPM) is a rare form of mesothelioma that carries a very poor prognosis. The 5-year overall survival is about 20% (±5.9). Survival is optimal for patients suitable for cytoreductive surgery (CRS) with Hyperthermic Intraperitoneal Chemotherapy (HIPEC), with a median OS ranging from 34 to 92 months. However, selecting patients for surgery remains a complex task and requires a careful preoperative workup, rational analysis of prognostic profiles, and risk prediction models. Systemic chemotherapy could be offered: (1) in the adjuvant setting for high-risk patients; (2) for patients not eligible for CRS; and (3) for those with recurrent disease. It mainly includes the combination of Platin compound with Pemetrexed or immunotherapy. The biology of DMPM is still largely unknown. However, progress has been made on some fronts, such as telomere maintenance mechanisms, deregulation of apoptosis, tyrosine kinase pathways, and mutation of BRCA1-associated protein 1 (BAP1). Future perspectives should include translational research to improve our understanding of the disease biology to identify druggable targets. We should also clear the role of immune checkpoint inhibitors and investigate new locoregional technologies, such as pressurized intraperitoneal aerosol chemotherapy (PIPAC) or normothermic intraperitoneal chemotherapy (NIPEC).

Malignant Mesothelioma of the Testes with Retroperitoneal Recurrence and Resection in an 80-Year-Old Male and Review of the Literature

Malignant mesothelioma of the testes is an aggressive, yet rare urogenital malignancy, accounting for an infinitesimally small number of oncologic diagnoses. This infrequent occurrence is accompanied by a relative lack of knowledge surrounding this disease, thus limiting management options beyond surgical intervention. Oftentimes, these malignancies present with a poor prognosis despite early intervention and only worsen in the event of metastatic spread with poor survival and limited response to treatment, if any. Our case documents positive patient outcomes following the use of aggressive surgical intervention in the management of a metastatic testicular mesothelioma. A healthy 80-year-old male with sudden painless testicular swelling requiring radical orchidectomy following failed initial conservative management. Pathologically, the specimen was diagnosed as malignant mesothelioma of the right testis with involvement of the tunica albuginea and tunica vaginalis. Following disease recurrence at 82 years of age, the patient subsequently opted for an open right-sided template non-nerve sparing retroperitoneal lymph node dissection which was undertaken without complication. Malignant mesothelioma of the testes remains an ominous diagnosis with historically poor outcomes and for which surgical intervention remains the mainstay of treatment. The retroperitoneal lymphatic drainage represents the most common route of metastatic spread for testicular tumours; however, retroperitoneal lymph node dissection has rarely been employed in this patient population and never in an individual of this age. Our findings contribute to the growing literature surrounding these rare malignancies and outline the importance of considering both patient autonomy and the clinical picture in disease management.

Ultrasonography of a giant adenomatoid tumor of the tunica vaginalis: A case report and review of the literature

Adenomatoid tumor is a kind of benign tumor, accounts for a low percentage of scrotal tumors. It usually locates in epididymis, less commonly, arises from the tunica albuginea, spermatic cord or tunica vaginalis of male's urogenital tract system. Here, we report a case of a 32-year-old male, which presented as a 6-month history of left scrotal swelling pain with a scrotal mass, and it had progressively enlarged over the last 1 month. The ultrasonography (US) described a giant well-defined hypoechoic mass in the left scrotum, a thick pedicle connected the mass and the left scrotal wall, and the pedicle had large blood vessels in it. Enhanced CT showed an irregular solid mass in the left scrotum, the left testicular artery was thickened to supply blood for the mass, and the radiologist mentioned it could not be excluded as a malignant lesion. The patient underwent left radical orchiectomy, the mass was diagnosed as an adenomatoid tumor of the tunica vaginalis by pathology. We review literature regarding adenomatoid tumors originating in the tunica vaginalis, summarize the ultrasonographic presentations, provide the idea of diagnosis and differential diagnosis to improve diagnostic accuracy and avoid unnecessary orchiectomy.

KMT2C mutation in a Chinese man with primary multidrug-resistant metastatic adenocarcinoma of rete testis: a case report

Background

Adenocarcinoma of the rete testis (AORT) is an extremely rare malignant tumor with poor prognosis and limited responsiveness to traditional chemotherapy. Few previous studies have focused on the molecular mechanisms underlying therapy resistance in AORT and further scrutiny is required to enable searches for targeted drugs to guide treatment selection.

Case presentation

The current case concerns a 55-year-old man with AORT who presented with isolated bone metastasis at initial diagnosis and experienced rapid disease progression after multi-line platinum-based combination chemotherapy. Next-generation sequencing revealed a novel somatic lysine methyltransferase 2C (KMT2C) c.5605 T > C mutation in exon 36 with an abundance of 49.27%. The patient received antiangiogenic drug treatment for 2 months but this was discontinued due to unacceptable anorexia and nausea. He survived for 12 months after diagnosis.

Conclusion

A potential correlation between AORT primary multi-drug resistance and KMT2C mutations is implied. Further studies are needed to determine the efficacy of PARP1/2 inhibitors for tumors with KMT2C mutations.

A Diagnostic Approach to Paratesticular Lesions with Tubulopapillary Architecture: A Series of 16 Serous Borderline Tumors/Low-Grade Serous Carcinoma & 14 Well-Differentiated Papillary Mesothelial Tumors and Mesothelioma

As there is limited literature on paratesticular tumors of müllerian and mesothelial origin, we reviewed archived cases of serous borderline tumors (n=15), low-grade serous carcinoma (n=1), well-differentiated papillary mesothelial tumors (WDPMT; n=2), and mesothelioma (n=12), for relevant clinicopathologic features. Molecular profiling data from the American Association for Cancer Research (AACR) GENIE registry was accessed for 8 additional patients with testicular mesothelioma. For tumors of mesothelial origin, the median age at surgical excision was 62 years, median size was 4.5 cm, and they consistently exhibited positivity for mesothelial markers (CK5/6, calretinin, WT1 and D2-40). Recurrent alterations of the NF2 gene were identified in 3 of 8 (38%) patients, and alterations of BAP1 and CDKN2A were relatively infrequent. While one patient with WDPMT had a recurrence, a second patient with WDPMT progressed to a biphasic mesothelioma two years after initial resection. For tumors of müllerian origin, the median age at surgical excision was 45 years, the median size was 2.5 cm, and these exhibited consistent positivity for ER, WT1 and PAX8. Although no recurrences were documented in patients with serous borderline tumors, a single patient with a low-grade serous carcinoma developed widely metastatic disease and died of disease-related complications. Our study emphasizes the need for close clinical follow-up in patients with WDPMT and highlights the prognostic significance of documenting invasive behavior in tumors of müllerian origin as they can have an aggressive clinical course. Finally, our results suggest that NF2 alterations may play an important role in the pathogenesis of testicular mesothelioma.

A case of spontaneous rete testis adenoma in a Sprague–Dawley rat

A 104-week-old male CD (SD) rat exhibited enlargement of the left testis. Microscopically, this mass was demarcated from the testis by fibrous connective tissue and characterized by cystic dilatation with single-layered columnar cells and papillary proliferation connected to the solid growth area without clear boundaries. In the solid growth area, cells were dissected into irregular alveolar nests by scant fibrous tissue with small blood vessels. The nuclei of proliferating cells were variable in size and round- to oval-shaped, and their cytoplasm was pale or eosinophilic and sometimes contained vacuoles or eosinophilic granules. Immunohistochemically, the tumor cells were positive for vimentin and cytokeratin (CK) 7. Since CK7 was exclusively positive in the rete testis epithelium of the naïve rat, it was valuable to diagnose this tumor as rete testis-originated. Based on these results and the lack of apparent pleomorphism, mitotic figures, and metastasis, the present case was diagnosed as rete testis adenoma.

Hospitalisation costs of malignant mesothelioma: results from the Italian hospital discharge registry (2001-2018)

OBJECTIVES

This paper aims to establish hospitalisation costs of mesothelioma in Italy and to evaluate hospital-related trends associated with the 1992 asbestos ban.

DESIGN

This is a retrospective population-based study of Italian hospitalisations treating pleura, peritoneum and pericardium mesothelioma in the period 2001-2018.

SETTINGS

Public and private Italian hospitals reached by the Ministry of Health (coverage close to 100%).

PARTICIPANTS

157 221 admissions with primary or contributing diagnosis of pleural, peritoneal or hearth cancer discharged from 2001 to 2018.Primary and secondary outcome measures: number, length and cost of hospitalisations with related percentages.

RESULTS

Each year, Italian hospitals treated a mesothelioma in 6025 admissions on average. Mean annual costs by site were €20 293 733, €3183 632 and €40 443 for pleura, peritoneum and pericardium, respectively. Pericardial mesothelioma showed the highest cost per admission (€6117), followed by peritoneal (€4549) and pleural cases (€3809). Percentage of hospitalisation costs attributable to mesothelioma was higher when it is located in pleura (53.4%) and pericardium (51.8%) with respect to peritoneum (41.2%). Overall annual hospitalisation cost, percentages of number and length of admissions showed an inverted U-shape, with maxima (of €25 850 276, 0.064% and 0.096%, respectively) reached in 2011-2013. Mean age at discharge and percentages of surgery and of urgent cases increased over time.

CONCLUSIONS

The highest impact of mesothelioma on the National Health System was recorded 20 years after the asbestos ban (2011-2013). Hospitals should expect soon fewer but more severe patients needing more cares. To study the disease prevalence could help assistance planning of next decade.

[Mesothelial proliferation of the tunica vaginalis testis]

Proliferative changes seen in reactive mesothelial hyperplasia of a hydrocele sac may mimic malignant mesothelioma. There is no immunohistochemical staining that reliably separates benign from malignant mesothelial proliferations. However, the combined analysis of BAP1 by immunohistochemistry and CDKN2A by FISH has been reported to yield both a high specificity and sensitivity in this differential diagnosis. In addition, the evaluation of risk factors such as asbestos exposure or prior traumata may be helpful for the correct diagnosis. Exclusion of stromal invasion, which is diagnostic for malign mesothelioma, is of utmost importance. Therefore, extended histological workup is essential.

Paratesticular tumors. A clinicopathological study from a single tertiary hospital in North India

OBJECTIVE

Paratesticular tumors (PTT) are rare and form a heterogenous group, ranging from benign to malignant high grade sarcomas. This study was undertaken to describe the clinicopathological spectrum of PTTs received over a 20-year period.

METHODS

All primary and secondary PTTs diagnosed from 2000 to 2019 in the pathology department of a tertiary care hospital in North India were retrospectively reviewed. Gross, histopathological features and immunohistochemistry (IHC) findings were correlated with clinical details.

RESULTS

A total of 169 intra-scrotal tumors were diagnosed during the study period, out of which there were 30 PTTs (in 27 patients) comprising 17.75%. Age range was 4 to 85 years (median 58 years). Benign PTTs were the commonest (n = 21, 70%), followed by metastasis to the paratesticular region (n = 6, 20%) and then primary malignant PTTs (n = 3, 10%). The commonest benign PTT was lipoma (n = 16, 76.19%), followed by adenomatoid tumor (n = 3, 14.28%) with one case each (4.76%) of cellular angiofibroma and hemangioma. Among primary malignant PTT, there were two cases of rhabdomyosarcoma, and one case of biphasic malignant mesothelioma. Metastatic tumors included four cases of prostatic adenocarcinoma, and one case each of pancreatic signet ring cell carcinoma and clear cell renal cell carcinoma.

CONCLUSION

PTTs show a wide clinicopathological spectrum. Benign PTTs are commoner than malignant PTTs. Meticulous grossing and histopathological examination supplemented by IHC is essential for an accurate diagnosis of this heterogenous class of tumors, which influences the role of adjuvant therapy and patient prognosis.

Rare Tumours of the Testis: Twelve Years of Experience

Rare tumours of the testis includes a wide variety of tumours. We aim to present clinical and histological characteristics of our patients with rare tumours of the testis. The medical records of 33 patients who were treated and followed-up for testicular rare tumours in our center between 2007 and 2020 were retrospectively reviewed. Of all the 243 testicular tumours, 222 cases (91.4%) were germ cell tumours and 21 cases (8.6%) were non-germ cell tumours. Thirty-three rare tumours of the testis including rare germ cell tumours and non-germ cell tumours were detected. The mean age of the patients at diagnosis was 34 years (range 18-68 years). The histological types of rare testicular tumours were as follows: teratoma 4.5% (n=11), sex-cord stromal tumours 4.5% (n=11), paratesticular tumours 3.2% (n=8), and the others [lymphoma 0.4% (n=1), mesothelioma 0.4% (n=1) and choriocarcinoma 0.4% (n=1)]. The median duration of follow-up was 32 months (range 1 to 256 months). None of the patients with non-metastatic disease stage developed recurrence after having received appropriate therapy. Metastatic disease was documented in 9 cases at the time of diagnosis (five patients with teratomas, two patients with Leydig cell tumour, one patient with choriocarcinoma and rhabdomyosarcoma). The most common subtypes of testicular rare tumours in our center was teratoma and sex-cord stromal tumours. Because of testicular rare tumours have different biological features and different clinical outcomes, the management of each tumour requires a different approach.

Malignant Mesothelioma of the Tunica Vaginalis Testis-A Malignancy Associated With Asbestos Exposure and Trauma: A Case Report and Literature Review

In this article, we report an unusual case of a malignant mesothelioma of the testis, presenting as hydrocele. The patient has a known medical history of trauma and occupational exposure to asbestos. The clinical features of this injury are discussed together with its immunohistochemistry. Surgical intervention is discussed due to the nature of this pathology.

Imaging appearance of cystic and solid mesothelioma of the tunica vaginalis

We present the case of a 32-year-old male who presented with a growing scrotal mass initially diagnosed as benign adenomatoid tumor on ultrasound 6 years prior. Repeat ultrasound showed an abnormal extra-testicular mass with nodular and cystic components and internal vascularity. A computed tomography scan of the abdomen and pelvis confirmed a right extra-testicular scrotal mass with cystic and solid enhancing components. The patient underwent radical orchiectomy and postoperative pathology diagnosed mesothelioma of the tunica vaginalis of the testis. Mesothelioma of the tunica vaginalis of the testis is an exceptionally rare disease. We discuss the risk factors, imaging features, and treatment strategies of the disease.

Malignant mesothelioma of the tunica vaginalis testis: a rare case and review of literature

Background

Malignant mesothelioma of the tunica vaginalis is a rare tumour which comprises less than 1% of all mesotheliomas.

Case presentation

69-years old patient with painful hard mass and hydrocele in the right scrotum to whom a right hydrocelectomy was performed. Any history of scrotal trauma or exposure to asbestos was not present. Excisional biopsy revealed a multinodular tumour with focal areas of necrosis and infiltrative growth. According to morphological and immunohistochemical findings, diagnosis of malignant biphasic mesothelioma of the tunica vaginalis testis was made. Two months after hydrocelectomy, right inguinal orchidectomy was performed. Post-surgical whole body CT scan revealed paraaortic and pararenal lymphadenopathy, likely to be metastatic. Adjuvant treatment with 6 cycles of cisplatin and pemetrexed was applied. After 3 cycles of chemotherapy, CT scan showed progression and the treatment was changed to gemcitabine 1 month after.

Conclusions

Although malignant mesothelioma of the tunica vaginalis is a rare malignancy, it poses a diagnostic challenge which can mimic common inguinal or scrotal diseases such as hydrocele. Despite aggressive surgical procedures or adjuvant therapies, the prognosis remains poor.

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.

Costs of medical care for mesothelioma

Malignant mesothelioma is a rare and devastating form of cancer with an increasing economic burden. We sought to describe the direct cost burden of mesothelioma to the US health system. A systematic literature review was performed to locate published estimates of the medical cost of mesothelioma. In addition, we performed an analysis of hospital discharge data from the National Inpatient Sample, Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality. We also reviewed publicly available legal settlements. We found that published estimates of the cost of medical care for mesothelioma are sparse, and differ with respect to nation, timeframe, and types of cost included. For the year 2014 in the United States, we estimated a mean cost per mesothelioma hospitalization of US$24,124 (95% confidence interval: US$20,819–US$28,983) and a total cost for hospital care of US$44,214,835. In conclusion, we found that reports describing the direct medical cost of care for mesothelioma in the United States are lacking, yet the per-patient cost of care is substantial, as evidenced by analyses of inpatient care and legal settlements.

Pathologic Considerations and Standardization in Mesothelioma Clinical Trials

The accurate diagnosis of mesothelioma is critical for the appropriate clinical management of this cancer. Many issues complicate making the diagnosis of mesothelioma including the presence of reactive mesothelial cells in benign pleural effusions, the heterogeneity of mesothelioma histopathology, the relatively high incidence of other epithelial malignancies that metastasize to the pleura, and primary sarcomas that arise within the pleura. Given the rapidly evolving field of molecular profiling and the need for translational correlates in mesothelioma clinical trials, the National Cancer Institute (NCI)-International Association for the Study of Lung Cancer-Mesothelioma Applied Research Foundation Clinical Trials Planning Meeting was convened in March 2017 to develop a consensus on standard pathology guidelines for future NCI-sponsored clinical trials in mesothelioma. This consensus statement covers recommendations for specimen handling, pathologic classification and diagnosis, biobanking, and tissue correlative studies.

Mesothelioma subtypes of the tunica vaginalis: a rare case report and review of histological criteria

Well-differentiated papillary mesothelioma (WDPM) is a rare histological subtype of mesothelioma arising from the tunica vaginalis. We present a case of a 23-year-old male with a palpable para-testicular lump of 3 years duration. Scrotal exploration revealed a grossly abnormal cystic appearance of his tunica vaginalis. An excision biopsy confirmed WDPM of the tunica vaginalis. The three subtypes of mesothelial tumours of the tunica vaginalis are described by their distinct histological features, tumour growth and reported prognosis. A summary of immunohistochemistry and the surgical management across the disease spectrum is provided. Recent clarification of the histological criteria of WDPM provides the opportunity for surgeons to offer a limited approach to managing this indolent tumour that mimics malignant mesothelioma. However, the lack of evidence on recurrence and progression rates in WDPM restricts most surgeons to performing a radical orchidectomy, as was performed in this case.

Testicular Mesothelioma: An Analysis of Epidemiology, Patient Outcomes, and Prognostic Factors

OBJECTIVES

To characterize demographic features, clinical characteristics, and oncologic outcomes of mesothelioma of the testis.

METHODS

A population based search was performed using the National Cancer Institute's SEER 18 database. Patients diagnosed with malignant mesothelioma of the male genital organs from 1973 to 2015 were identified. Data on patient age, race, tumor laterality, histologic subtype, tumor extent, tumor size, tumor grade, treatment, cause of death, and survival months was collected. Primary outcomes were overall survival (OS) and disease-specific survival (DSS).

RESULTS

A total of 113 patients with testicular mesothelioma were identified. The 5-year OS and DSS for all patients was 49% and 58%, and the 10-year OS and DSS was 33% and 45%, respectively. Biphasic mesotheliomas were associated with worse OS compared to general mesotheliomas and epithelioid subtypes (P = .043 and P = .039, respectively). Median survival time was not reached in patients with T1 disease while OS was 1.7 years and DSS was 1.8 years for patients with T4 disease (OS P = .002, DSS P <.001). Tumors greater than or equal to 4 cm were associated with worse OS and DSS (OS P = .025, DSS P = .047).

CONCLUSION

This rare malignancy has significant mortality, with poor survival associated with biphasic subtypes, higher disease stage, and a critical tumor size cutoff of 4 cm.

[Tunica albuginea adenomatoid tumor. A challenging case managed conservatively]

The adenomatoid tumors are rare benign mesothelial lesions that in males affect mainly the epididymis. They account for over one third of paratesticular tumors, and the treatment of choice has been surgical excision. The origin in testicular parenchyma or the tunica albuginea is extremely rare. Clinical signs and imaging studies are often inconclusive in differentiate from a more common malignant intratesticular solid tumour, which can result in unnecessary orchiectomies. We present a case of adenomatoid tumor of tunica albuginea where clinical suspicion and intraoperative frozen section analysis led to a partial orchiectomy.

Malignant Peritoneal Mesothelioma in the setting of a Ventriculo-Peritoneal Shunt: A novel clinical presentation

We report a case of malignant peritoneal mesothelioma (MPM) in a 31-year-old male with history of cerebral palsy, hydrocephalus, and ventriculoperitoneal shunt (VPS) placed since infancy. He presented with fever, abdominal pain and distension. Computed tomography scan revealed a thick-walled rim-enhancing fluid collection, interpreted as pseudocyst. Intraoperatively, diffuse nodular peritoneal thickening with adhesions was demonstrated. The resection specimen consisted of multiple membranous fragments displaying firm nodules. Microscopic examination revealed a tumefactive malignant-appearing epithelioid proliferation involving the peritoneum, focally invading the underlying fat. Immunohistochemically, the tumor cells expressed keratin AE1/AE3, CK7, CK5/6, Calretinin, WT1 and D2-40, and were negative for CEA and MOC31. The findings were consistent with MPM, epithelioid type. The patient's condition continued to decline with increasing abdominal distension during the month following the original diagnosis. While atypical mesothelial hyperplasia has been described in association with long standing VPS, well-documented cases of MPM have not been previously reported in such context.

Malignant Mesothelioma of the Tunica Vaginalis Testis: Outcomes Following Surgical Management Beyond Radical Orchiectomy

OBJECTIVE

To describe clinical management and outcomes of a cohort of patients with malignant mesothelioma of the tunica vaginalis testis (MMTVT) who received treatments beyond radical orchiectomy.

METHODS

Patients with confirmed MMTVT at a single tertiary care institution were identified. Treatments, pathologic outcomes, and survival were recorded. Prognostic variables associated with survival were analyzed with a Cox proportional hazards model and Kaplan-Meier curves.

RESULTS

Overall, 15 patients were included. Initial presentation was a scrotal mass in 7 of 15 (47%) and hydrocele in 5 of 15 (33%) patients. Clinical staging revealed enlarged nodes in 5 of 15 (33%) patients. Radical orchiectomy was the initial treatment in 5 of 15 (33%) patients. Positive surgical margins were found in 6 of 14 (43%) radical orchiectomies and were associated with worse survival (P = .007). The most frequent histologic subtype was epithelioid, associated with better survival (P = .048). Additional surgeries were performed on 12 of 15 (80%) patients. Pathologic examination revealed MMTVT in 6 of 12 (50%) hemiscrotectomies, 7 of 8 (88%) retroperitoneal lymph node dissections, 1 of 7 (14%) pelvic lymph node dissections, and 10 of 10 (100%) groin dissections. Five patients received adjuvant chemotherapy. Two also received adjuvant radiation therapy. Three patients with lymph node involvement remain no evidence of disease over 6 years after diagnosis. After a median follow-up of 3.5 years (interquartile range: 1.2-7.2), 5 patients have died, all of MMTVT; the median overall survival has not been reached. Common sites of relapse were lungs (5 of 7) and groin (3 of 7).

CONCLUSION

The pattern of metastatic spread of MMTVT is predominantly lymphatic. Nodes in the retroperitoneum and the groin are commonly involved. Prognosis is poor, but there may be a role for aggressive surgical resection including hemiscrotectomy, and inguinal and retroperitoneal lymph nodes.

Epidemiology of mesothelioma of the pericardium and tunica vaginalis testis

PURPOSE

Malignant mesothelioma most commonly arises in the pleura and peritoneum but also occurs rarely at other anatomical sites with mesothelial tissue, namely, the pericardium and tunica vaginalis testis (TVT). This review provides a better understanding of the epidemiology of mesothelioma of these extrapleural sites.

METHODS

We conducted a systematic review of the epidemiologic and clinical literature on pericardial mesothelioma and mesothelioma of the TVT. We also analyzed U.S. Surveillance, Epidemiology, and End Results cancer registry data to describe incidence patterns of these malignancies.

RESULTS

An etiologic role of asbestos exposure has been hypothesized for pericardial and TVT mesotheliomas, but no analytical case-control epidemiologic studies exist to test this relationship. A substantial proportion of cases with these malignancies report no known asbestos exposure. In large occupational cohorts with heavy asbestos exposures, no cases of pericardial or TVT mesothelioma have been reported. Trends in the incidence of these malignancies do not match those of pleural mesothelioma, which correspond to historical trends of commercial asbestos use. A male preponderance of pericardial mesothelioma is not evident.

CONCLUSIONS

In the absence of analytic epidemiologic studies, the etiologic role of environmental risk factors for mesothelioma of the pericardium and TVT remains elusive.

The legacy of the F344 rat as a cancer bioassay model (a retrospective summary of three common F344 rat neoplasms)

The Fischer 344 (F344) rat was used by the National Toxicology Program (NTP) for over 5 decades for toxicity and carcinogenicity studies. However, in 2006, the NTP decided to switch to a different rat stock due largely to high background control incidences of Leydig cell tumors (LCTs) and mononuclear cell leukemia (MNCL), also known as large granular lymphocytic (LGL) leukemia. In the current review, we aim (1) to provide a summary of NTP bioassays with treatment-associated effects involving MNCL and LCTs in addition to male F344-specific tunica vaginalis mesothelioma (TVM); (2) to describe important pathobiological differences between these F344 rat tumor responses and similar target tissue-tumor response in humans; and (3) to present the NTP reasons for switching away from the F344 rat. We show that due to the highly variable background incidence of F344 MNCL, more reliance on historical control data than is usual for most tumor responses is warranted to evaluate potential effect of any chemical treatment in this rat strain. The high spontaneous incidence of LCTs in the testes of male F344 rats has made this tumor endpoint of little practical use in identifying potential testicular carcinogenic responses. TVM responses in F344 rats have a biological plausible relationship to LCTs unlike TVM in humans. Given their high spontaneous background incidence and species-specific biology, we contend that MNCL and LCT, along with TVM responses, in F344 rat carcinogenicity studies are inappropriate tumor types for human health risk assessment and lack relevance in predicting human carcinogenicity.

Preoperative cytological diagnosis of malignant mesothelioma of tunica vaginalis

Malignant mesothelioma of tunica vaginalis testis is a rare aggressive neoplasm with ∼200 cases reported so far. A correct preoperative diagnosis of this rare tumor is difficult. Fine-needle aspiration cytology (FNAC) is a rapid and inexpensive diagnostic tool that may prove helpful in such cases. Very few cases have been diagnosed on cytology so far, and the descriptions of the cytological features have rarely been described in the literature. In this report we present the cytological features of malignant mesothelioma of tunica vaginalis testis which was diagnosed by FNAC and subsequently confirmed by histopatholoy and immunohistochemical (IHC) studies.

Malignant Mesothelioma Diagnosed by Bronchoscopic Biopsy

Malignant mesothelioma is a rare malignant neoplasm that arises from mesothelial surfaces of the pleural cavity, peritoneal cavity, tunica vaginalis, or pericardium. Typically, pleural fluid cytology or closed pleural biopsy, surgical intervention (video thoracoscopic biopsy or open thoracotomy) is conducted to obtain pleural tissue specimens. However, endobronchial lesions are rarely seen and cases diagnosed from bronchoscopic biopsy are also rarely reported. We reported the case of a 77-year-old male who was diagnosed as malignant mesothelioma on bronchoscopic biopsy from obstructing masses of the endobronchial lesion.

Perineal and colonic metastases in two cases of malignant mesothelioma

Two patients with rare sites of metastatic pleural mesothelioma are presented and the literature on similar cases is examined. One patient developed colonic metastases from a sarcomatoid mesothelioma. Another patient with epithelioid mesothelioma developed perineal metastases.