Primary malignant gonadal mesotheliomas and asbestos

Intratesticular Mullerian Serous Borderline Tumor With Microinvasion: A Rare Tumor and Review of the Literature

Ovarian-type (ie, Mullerian) epithelial tumors occurring in the testicular and paratesticular regions are exceptionally rare, with only a handful reported worldwide. Serous tumors are the most frequently encountered subtype among these rare tumors. The pathogenesis of these tumors within the testicular and paratesticular regions remains a subject of intrigue and debate, with various hypotheses attempting to explain their presence in the paratestis region, where most tumors occur. However, our understanding of the pathogenesis of intratesticular tumors is limited. To date, 11 known examples of intratesticular serous Mullerian tumors have been reported globally. In this report, we present an extraordinary tumor, an intratesticular Mullerian serous borderline tumor with foci of microinvasion, in a 38-year-old male patient. This tumor exhibits histological features similar to their ovarian counterparts and is confirmed through an immunohistochemical panel. Our report underscores the extreme rarity of these tumors, emphasizes the importance of heightened awareness among clinicians and pathologists, and provides valuable insights into their complex development and histogenesis. This contribution aims to enhance diagnostic precision and optimize therapeutic strategies for similar tumors.

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.

Localized Malignant Peritoneal Mesothelioma (LMPeM) in Women: A Clinicopathologic Study of 18 Cases

Localized malignant peritoneal mesothelioma is a rare tumor with limited information in the literature. In this study, we present our experience with 18 cases seen in our hospital over a period of 43 years (1978 to 2021). Patients' median age was 55 years (y) (range: 33 to 79 y) and most of them were Caucasians. Patients presented with abdominal pain (11), ascites and right leg swelling (1), abdominal mass (1), and as incidental finding (1). Thirty percent of patients reported asbestos exposure, and all patients with available information had family history of tumors; a third had personal history of tumors. Seventy-seven percent had some form of abdominopelvic surgery and/or inflammatory process. Most cases had microscopic features typically seen in malignant mesothelioma; however, some cases had confounding features such as signet-ring cells, spindle cells, clear cell changes, and adenomatoid tumor-like appearance. BAP-1 by immunohistochemistry was lost in 1/3 cases. Only 1 patient underwent genetic testing and had an MSH2 germline mutation. Homozygous deletion of CDKN2A by FISH was not found in 1 tested case, although next-generation sequencing identified a CDKN2A pathogenic mutation. 16/18 (88%) had surgical treatment, and some also received adjuvant chemotherapy. The mean overall survival (OS) of our patients was 80.4 months (95% confidence interval: 54.3-106.52); the 3-year OS was 79%, while the 5-year OS was 52.6%. Fifty-three percent of patients had recurrences and 20% had tumor progression. Although the limited sample precludes definitive conclusions, small tumor size, low-grade cytology, and low mitotic index appeared to be associated with an indolent behavior.

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.

Primary Ovarian Mesothelioma: A Case Series with Electron Microscopy Examination and Review of the Literature

Primary ovarian mesothelioma is a rare, aggressive neoplastic disease with a poor prognosis. At onset, the tumor is only rarely limited to the ovaries and usually already widespread in the peritoneum. The rarity of this entity and the difficulties differentiating it from either ovarian carcinoma or peritoneal mesothelioma may lead to frequent misdiagnoses and may raise some concerns about its histogenesis. Thus, reporting such rare cases is fundamental to gain greater awareness of this neoplasm and try to answer unsolved questions. Herein, we described four cases of histological diagnoses of ovarian mesothelioma extrapolated by the regional mesothelioma register of Apulia (southern Italy). In all cases, a detailed medical history was collected according to national mesothelioma register guidelines. A broad panel of antibodies was used for immunohistochemistry to confirm the diagnoses. Moreover, ovarian tissue samples were also examined by transmission and scanning electron microscopy, detecting asbestos fibers and talc crystals in two cases. Because of the few cases described, we reviewed the English literature in the Medline database, focusing on articles about ovarian mesothelioma "misclassification", "misdiagnosis", "diagnostic challenge" or "diagnostic pitfall" and on unsolved questions about its histogenesis and possible risk factors.

Serous Ovarian Cancer Caused by Exposure to Asbestos and Fibrous Talc in Cosmetic Talc Powders-A Case Series

OBJECTIVE

Asbestos is a known cause of ovarian cancer. We report 10 cases of serous ovarian cancer among users of Johnson & Johnson (J&J) asbestos-containing "cosmetic" talc products.

METHODS

We conducted an asbestos exposure assessment during talc application and analyzed surgical tissues and talc containers for asbestos and talc.

RESULTS

Talc was found in all cases and tremolite and/or anthophyllite asbestos was found in 8/10 cases. The asbestos fibers found in the "cosmetic" talc containers matched those found in tissues. We estimated inhaled asbestos dose ranged from 0.38 to 5.18 fiber years.

CONCLUSION

We provide evidence that the inhaled dose of asbestos/fibrous talc from "cosmetic" talc use causes ovarian cancer. The unique combination of the types of asbestiform minerals detected in cancerous tissue and "cosmetic" talc is a fingerprint for exposure to asbestos-containing talc.

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.

The necessity of a more aggressive initial surgical treatment in patients with mesothelioma of the testicular tunica vaginalis

Mesothelioma of the tunica vaginalis of the testis (MTVM) is a rare tumor encountering for less than 1% of mesothelioma. Patients suffering from these tumors have poor survival due to local and distant metastasis despite treatment. Actually, no specific treatment recommendations exist for this tumor, yet radical orchidectomy is the gold standard in limited disease. We herein report the case of a 71 patient with MTVM who underwent radical orchidectomy without inguinal lymph node dissection and recurred 2 years later with metastasis in pelvic and mediastinal lymph nodes. Despite systemic chemotherapy combining pemetrexed, bevacizumab and Cisplatinum, the disease relapsed eight months later with multiple metastatic lung nodules leading to a treatment shift. We believe that systematic inguinal-iliac lymph node resection should be included in the initial treatment of this tumor.

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.

Malignant Mesothelioma of the Vaginal Tunic and Peritoneum in a Young Stallion

Mesothelioma is a rare malignancy in horses. This report describes a case in which marked hemoperitoneum, moderate anemia, and moderate dependent edema were the presenting clinical signs in a 2-year-old Standardbred stallion with mesothelioma of the vaginal tunic. On necropsy, approximately 40 L of dark red fluid distended the abdomen. A dark red mass infiltrated and effaced the right pampiniform plexus, and red nodular masses were present multifocally on the parietal and visceral peritoneal surfaces. Histopathologically, the masses were composed of malignant spindle cells with a sarcomatoid appearance. Using immunohistochemistry, tumor cells were cytokeratin and vimentin positive and factor VIII-related antigen negative: compatible with a diagnosis of mesothelioma. This is the first report of mesothelioma arising from the vaginal tunic of a horse with subsequent spread to the peritoneum. This case adds additional information regarding the clinical presentation and behavior of mesothelioma originating from the vaginal tunic in horses.

A Contemporary Review of Common Adult Non-germ Cell Tumors of the Testis and Paratestis

This article provides a comprehensive review of non-germ cell tumors of the testis and paratestis in adults, incorporating the latest 2016 World Health Organization updates. Clinical features, gross pathologic findings, key morphologic details, immunohistochemical profiles, and differential diagnoses are covered, with an emphasis on how to resolve commonly encountered, and sometimes difficult, differential diagnoses.

Images - Well-differentiated papillary mesothelioma of the tunica vaginalis

Well-differentiated papillary mesothelioma (WDPM) is a rare mesothelial tumour occurring in the tunica vaginalis of the testicle. The pathological classification of paratesticular mesothelial tumours is controversial and continues to evolve in the literature. Diagnostic criteria of one subtype, WDPM, are histological and include the following: 1) papillary or tubular-papillary architecture; 2) bland nuclear cytology; 3) low mitotic activity; 4) lined by a single row of cuboidal cells; and 5) absence of stromal invasion.1,2 This report presents issues of diagnosis of this rare pathology with imaging from an example case.

Malignant Mesothelioma of Tunica Vaginalis Testis: Macroscopic and Microscopic Features of a Very Rare Malignancy

Malignant mesothelioma of the tunica vaginalis testis (MMTVT) is an extremely rare tumour, usually mimicking benign pathologies of the scrotum.

Our case is an 84-year-old male patient who appealed with a painless, left-sided scrotal swelling longer than 2 months. Although the level of tumour markers was normal, ultrasonographic examination results forced us to perform an inguinal scrotal exploration. Multiple small papillary tumours, both on tunica vaginalis and tunica albuginea, were detected intraoperatively. Due to these findings, radical orchiectomy was performed.

A pathological evaluation showed malignant mesothelioma (MM) of the tunica vaginalis testis. Exposure to asbestos is a well-known risk factor. Furthermore, a history of trauma, herniorrhaphy and chronic hydroceles is blamed as a possible risk factor. Scrotal ultrasonography is the mainstay of primary diagnosis and, therefore, it should not be overlooked when dealing with benign scrotal cysts or hydroceles, which are very common pathologies at these decades, too.

Radical inguinal orchiectomy is the primary treatment choice for localised MMTVT disease, whereas in signs of lymph node metastasis, inguinal lymph node dissection is required. Radical resection should be completed with chemotherapy and/or radiotherapy for an advanced or recurrent disease. This case, which is very rarely reported in the literature and detected during inguinal exploration, along with the pathological works that supported the diagnosis, was presented with this report.

Malignant mesothelioma of the tunica vaginalis testis: A case report and literature review

Malignant mesothelioma of the tunica vaginalis testis is an extremely rare tumor without specific clinical manifestations, mainly including hydrocele formation and a painless mass. We herein present the case of a patient with hydrocele of the left testis, without any other complaints. Tunica vaginalis subinvolution was performed, and postoperative pathological examination revealed a malignant mesothelioma arising from the left tunica vaginalis testis. Whole-body positron emission tomography-computed tomography (PET-CT) and subsequent abdominal and pelvic magnetic resonance imaging (MRI) revealed no evidence of local lymphadenopathy. Radical left orchiectomy was performed after the pathological diagnosis. The pathological examination after the second surgery demonstrated that the tumor had invaded the adjacent periorchium and spermatic cord, but there was no evidence of local lymph node metastasis. Pemetrexed and cisplatin were administered at a dose of 900 and 130 mg, respectively, on the first day of a 28-day cycle. After 6 months of therapy, the disease had not progressed on abdominal and pelvic PET-CT and MRI. The patient was still followed up in our urology outpatient clinic at the time of the present report. Although testicular hydrocele is a common and easily diagnosed condition, detailed medical history and physical examination are required. Thus, when clinicians encounter patients with testicular hydrocele, a variety of possible causes must be considered, including testicular or paratesticular tumors, even rare tumors such as mesothelioma of the tunica vaginalis testis.

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.

Mesothelioma of the Tunica Vaginalis Testis: Report of 2 Cases with Asbestos Occupational Exposure

We report here 2 cases of malignant mesothelioma of the tunica vaginalis testis. A 67-year-old man with a left testicular mass was referred for left inguinal orchidectomy. Histologic examination showed a malignant mesothelioma of epithelial type. There is no evidence of recurrence at 2-year follow-up. The patient had been exposed to asbestos 12 years previously for a 30-year period. An 80-year-old man presented a 5-year history of scrotal swelling. Clinical examination revealed a hydrocele. The patient underwent resection of the tunica vaginalis through scrotal incision. Microscopic examination showed a malignant mesothelioma of biphasic type. There is no evidence of recurrence at 2-year follow-up. The patient had been exposed to asbestos 52 years previously for a 5-year period.

Malignant mesothelioma of tunica vaginalis: an extremely rare case presenting without risk factors

Testicular tumours have many different manifestations, including hydrocele formation. Herein, we present an extremely rare case of testicular mesothelioma presenting with left hydrocele, but without risk factors. Left radical inguinal orchidectomy was performed, and pathological examination revealed a malignant mesothelioma of the tunica vaginalis of the testis. No infiltration of the spermatic cord was evident, and upon advanced radiological evaluation, no sign of metastasis was detected. Follow-up was still ongoing in our urology outpatient clinic at the time of this report. Although hydrocele is a simple and common condition that is easy to diagnose, a detailed investigation should be performed. Thus, when encountering a patient with hydrocele, the clinician should evaluate the possibility of the presence of an underlying testicular/paratesticular tumour, including a rare one such as mesothelioma of the tunica vaginalis.

Malignant paratesticular mesothelioma

Mesothelioma of the tunica vaginalis testis (MTVT) is a rare tumor that usually affects patients after the sixth decade of life. Exposure to asbestos is a known risk factor. Enlargement of the scrotal volume is the most common initial clinical manifestation, and about 15% of cases present metastasis at diagnosis. The treatment relies on surgical resection while the role of adjuvant chemotherapy and radiotherapy remains unclear. The prognosis for patients is generally poor, with a lethal outcome in 30% over a 24-month period. The authors report a case of a 62-year-old patient with the diagnosis of MTVT without a history of asbestos exposure. After surgical treatment, metastatic disease ensued. Chemotherapy was initiated, but could not be continued due to marked and fast clinical deterioration. The authors call attention to the difficulty of early diagnosis of MTVT due to a nonspecific clinical picture, the lack of action by the patient when the scrotal enlargement was first noticed, and the lack of tumor markers. Delayed diagnosis is definitely related to unfavorable prognosis.

Malignant paratesticular mesothelioma

Mesothelioma of the tunica vaginalis testis (MTVT) is a rare tumor that usually affects patients after the sixth decade of life. Exposure to asbestos is a known risk factor. Enlargement of the scrotal volume is the most common initial clinical manifestation, and about 15% of cases present metastasis at diagnosis. The treatment relies on surgical resection while the role of adjuvant chemotherapy and radiotherapy remains unclear. The prognosis for patients is generally poor, with a lethal outcome in 30% over a 24-month period. The authors report a case of a 62-year-old patient with the diagnosis of MTVT without a history of asbestos exposure. After surgical treatment, metastatic disease ensued. Chemotherapy was initiated, but could not be continued due to marked and fast clinical deterioration. The authors call attention to the difficulty of early diagnosis of MTVT due to a nonspecific clinical picture, the lack of action by the patient when the scrotal enlargement was first noticed, and the lack of tumor markers. Delayed diagnosis is definitely related to unfavorable prognosis.

Localized Intrasplenic Mesothelioma: A Case Report

Malignant mesothelioma is a primary neoplasm of the serosal membranes that usually presents with a diffuse pattern of growth. However, cases of localized mesotheliomas have been described. The predominant localization is the pleura; peritoneum and pericardium being rarer localizations. Only few cases of true intraparenchymal mesothelioma arising in organs such as liver, gonads, lung, and pancreas have been described. We report a case of an otherwise healthy 48-year-old man without asbestos exposure with a nodule of 3 cm in diameter, localized in the spleen, discovered incidentally at the ultrasonographic examination, for which histopathological and immunohistochemical findings were consistent with epithelioid mesothelioma: large round cells with eosinophil dense cytoplasm and macronucleoli and with immunohistochemical positivity for pancytokeratins, calretinin, Wilms tumor-1, and others markers of mesothelial differentiation. The diagnosis of localized intrasplenic epithelioid malignant mesothelioma was carried out. To the best of our knowledge, this is the first case of a localized intrasplenic mesothelioma published in the indexed literature.

Mesothelioma of tunica vaginalis testis and asbestos exposure

Study Type - Therapy (case series). Level of Evidence 4. What's known on the subject? and What does the study add? Mesothelioma of the tunica vaginalis testis is a rare tumour. From 2000 to 2010, 13 mesothelioma of the tunica vaginalis testis cases were reported in the most populated and industrialized region in Italy. Asbestos exposure was documented in two-thirds of these cases.

OBJECTIVE

• To describe cases of mesothelioma of the tunica vaginalis testis (MTVT) recorded in the Lombardy Mesothelioma Registry between 2000 and 2010.

METHODS

• The Lombardy Mesothelioma Registry, established in 2000, collects data regarding all incident cases of mesothelioma of the pleura, peritoneum, pericardium and tunica vaginalis testis that have been diagnosed in the population of the Lombardy region. • These data include a detailed clinical report and a complete occupational history for each MTVT patient, with the latter including details of the industrial sector involved, the patient's job, and the specific tasks performed. To address the potential for asbestos exposure outside the work environment, the residential history, lifestyle habits and hobbies of the patient, as well as job information for all subjects living with the patient, are also collected. • Records were reviewed and discussed by a panel of experts.

RESULTS

• Thirteen cases of MTVT were reported between 2000 and 2010. • The age-standardized incidence rate of MTVT for the Lombardy region of Italy is 0.2 cases per million individuals/year. • Asbestos exposure was documented in 8 of the 12 (67%) interviewed cases.

CONCLUSIONS

• Asbestos exposure was associated with a higher proportion of MTVT cases than previously reported in the literature. These results confirm the aetiological role for asbestos in the pathogenesis of MTVT. • The results of this study also highlight the importance of obtaining detailed occupational histories and lifestyle habits from patients, particularly by trained interviewers.

Mesothelial neoplasms presenting as, and mimicking, ovarian cancer

Mesotheliomas of the abdominal cavity are rare tumors that primarily involve the peritoneum, mesentery, and omentum. The involvement of the viscera is usually secondary to bulky and extensive serosal disease. We describe 7 cases of mesothelioma in which the initial manifestation was that of an ovarian mass. All patients underwent surgery with a primary diagnosis of ovarian cancer. Clinical histories, gross features, and histology slides were reviewed. Immunostains were performed on all cases and electron microscopy was performed in 2 cases. The patients ranged in age from 22 to 52 years and the lesions ranged in size from 3.8 to 9 cm. Of the 7 cases, 4 were predominantly cystic and 3 were solid. Histologically, all cystic tumors were multicystic mesothelioma, whereas the 3 solid tumors were diffuse malignant mesotheliomas. One patient had a borderline mucinous tumor with the mesothelioma occurring as a mural nodule, an association not described earlier. The oldest patient in this series had a diffuse malignant mesothelioma of the peritoneum with predominant ovarian surface involvement. Mesothelial neoplasms can present as ovarian masses in young women. Awareness of this presentation is important to establish appropriate management.

Nonpulmonary outcomes of asbestos exposure

The adverse pulmonary effects of asbestos are well accepted in scientific circles. However, the extrapulmonary consequences of asbestos exposure are not as clearly defined. In this review the potential for asbestos to produce diseases of the peritoneum, immune, gastrointestinal (GIT), and reproductive systems are explored as evidenced in published, peer-reviewed literature. Several hundred epidemiological, in vivo, and in vitro publications analyzing the extrapulmonary effects of asbestos were used as sources to arrive at the conclusions and to establish areas needing further study. In order to be considered, each study had to monitor extrapulmonary outcomes following exposure to asbestos. The literature supports a strong association between asbestos exposure and peritoneal neoplasms. Correlations between asbestos exposure and immune-related disease are less conclusive; nevertheless, it was concluded from the combined autoimmune studies that there is a possibility for a higher-than-expected risk of systemic autoimmune disease among asbestos-exposed populations. In general, the GIT effects of asbestos exposure appear to be minimal, with the most likely outcome being development of stomach cancer. However, IARC recently concluded the evidence to support asbestos-induced stomach cancer to be "limited." The strongest evidence for reproductive disease due to asbestos is in regard to ovarian cancer. Unfortunately, effects on fertility and the developing fetus are under-studied. The possibility of other asbestos-induced health effects does exist. These include brain-related tumors, blood disorders due to the mutagenic and hemolytic properties of asbestos, and peritoneal fibrosis. It is clear from the literature that the adverse properties of asbestos are not confined to the pulmonary system.

Mesothelioma of the tunica vaginalis: a series of eight cases with uncertain malignant potential

Well-differentiated papillary mesotheliomas have rarely been reported to involve the testis tunica vaginalis. While the classic histology of the originally described well-differentiated papillary mesotheliomas consisted of papillae lined by a single layer of bland cuboidal cells, more complex architectural patterns have been described. This report details our experience with eight paratesticular mesotheliomas that span the histological spectrum from classic well-differentiated papillary mesotheliomas to those with more complex patterns. We attempt to determine whether there are prognostic or immunohistochemical differences between these lesions and 28 diffuse malignant mesotheliomas. All cases had papillary/tubulopapillary in addition to more complex architectures (cribriform, condensed) and none showed evidence of invasion. Mitotic figures were present in seven cases and averaged 2.1 mitosis per 50 h.p.f. All cases showed <or=1% of positive cells staining for Ki-67 and p53, and only one case stained positive for GLUT-1 in comparison with 50% positivity for GLUT-1 in diffuse mesotheliomas. Of five patients with follow-up information of more than 1 year, three patients were alive at 2, 3 and 9 years, and two died of unknown causes at 5 and 47 years, suggesting that these lesions behave more indolently than typical malignant mesotheliomas of the tunica vaginalis. If these cases were diffuse malignant mesotheliomas, one would have expected at least some of the patients to have died of disease within a couple of years after diagnosis. However, detailed and long-term follow-up were not sufficiently available to reach definitive conclusions on the true biological behavior of these tumors. The morphological continuum noted between our cases and classic well-differentiated papillary mesotheliomas, combined with their immunohistochemical profile and indolent behavior, contrasts with that of diffuse malignant mesotheliomas. We propose that these tunica vaginalis mesotheliomas, which are more complex than the classic well-differentiated papillary mesotheliomas, and yet are not overtly histologically malignant, be classified as 'mesotheliomas of uncertain malignant potential'.

Localized intrapancreatic malignant mesothelioma: a rare entity that may be confused with other pancreatic neoplasms

Malignant mesothelioma usually presents with diffuse involvement of the pleura or peritoneum. Circumscribed or localized malignant mesothelioma has been described in these locations, as well as the viscera, in which case it may cause diagnostic confusion with other, more common entities. Herein, we describe the first well-documented case of primary intrapancreatic malignant mesothelioma in the English literature. The patient was an otherwise healthy 39-year-old woman who presented with a symptomatic mass in the head of the pancreas that was completely resected via pancreaticoduodenectomy. The tumor was composed of cysts, papillae, and tubules lined by cells with abundant eosinophilic cytoplasm and immunohistochemically expressed CA-125, calretinin, and D2-40. Follow-up revealed no evidence of residual or recurrent disease 32 months after surgery. This report also describes the clinical and pathologic characteristics of an intrapancreatic mesothelioma and provides a review of the literature regarding entities that may be considered in the differential diagnosis of this tumor.

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.

Extrathoracic Mesothelial Proliferations and Their Mimics

Mesothelial proliferations, either reactive or neoplastic in nature, often pose difficult diagnostic dilemmas. Electron microscopy continues to be a gold standard in the identification of mesothelial differentiation. However, it is very common to apply long panels of antibodies for that purpose. In most cases, light microscopy and immunohistochemistry will solve the problem. However, the definitive, specific, and sensitive immunohistochemical marker is still lacking. This is particularly true in peritoneal and testicular mesothelial tumors, in which common embryologic origin with epithelial elements results in overlapping immunohistochemistry and morphology. The particularities of peritoneal and testicular mesothelial proliferations, and the main tumors that may mimic them in these sites, as well as the value and limitations of immunohistochemistry and electron microscopy in their differential diagnosis are the subject of this review.

Calretinin: diagnostic utility in the female genital tract

The utility of calretinin was first described in the diagnosis of mesothelioma. In the female genital tract, calretinin was initially reported in Wolffian remnants and related lesions and later used in the diagnosis of sex cord stromal tumors of the ovary, endometrial stromal tumors with sex cord-like differentiation, and uterine tumors resembling sex cord tumors of the ovary. This review discusses calretinin expression in normal tissues of the female genital tract and highlights its potential utility in the diagnosis of these subsets of neoplasms with emphasis to tumors that may constitute a problem in their differential diagnosis. In particular, the limited utility of calretinin in the diagnosis of sex cord stromal tumors of the ovary, in the differential diagnosis between mesothelioma and serous tumors involving the ovary and/or peritoneum, and in the differential diagnosis between Wolffian lesions and endometrial carcinoma are addressed.

Primary localized malignant biphasic mesothelioma of the liver in a patient with asbestosis

We report a case of primary localized malignant biphasic mesothelioma of the liver in a 66-year-old man associated with asbestosis. The tumor was detected as a hepatic nodule, 4 cm in diameter, in the right lobe (S8 segment) on CT scan. Histopathological examination demonstrated an intrahepatic tumor with central necrosis consisting of a papillary epithelioid pattern on the surface of the liver, microcystic (microglandular or adenomatoid) pattern mainly in the subcapsular area and sarcomatoid pattern intermingled with microcystic pattern in the major part of the hepatic nodular tumor. Tumor cells, especially of epithelioid type, showed distinct immunoreactivity for mesothelial markers (WT-1, calretinin, D2-40, CK5/6, mesothelin, thrombomodulin) and no immunoreactivity for epithelial (adenocarcinoma) markers (CEA, CD15, BerEP4, BG8, MOC31). P53 immunoreactivity was detected focally in papillary epithelioid tumor cells and extensively in microcystic and sarcomatoid components, suggesting that the papillary epithelioid mesothelioma arose on the surface of the liver, and tumor cells showing microcystic and sarcomatoid patterns invaded and grew into the liver. To date, this is the first case of primary localized malignant biphasic mesothelioma of the liver, since all three primary hepatic mesotheliomas reported so far were epithelioid type.

The immunohistochemical profile of malignant mesotheliomas of the tunica vaginalis: a study of 20 cases

Malignant mesotheliomas of the testis arise from the tunica vaginalis, formed from the evagination of the abdominal peritoneum into the scrotum. The immunohistochemical profile of the tunica vaginalis and associated neoplasms is often extrapolated from thoracic studies. Testicular series are uncommon, usually derived from previous case studies and literature reviews. The immunohistochemical findings in 20 cases originally diagnosed as malignant mesotheliomas are presented. Archival testicular malignant mesothelioma specimens from 1959 to 2004 were collected from hospitals throughout the United Kingdom and from the authors' own archives. Hematoxylin and eosin-stained sections were reviewed, and selected sections from each case were then examined using an immunohistochemical panel of eight antibodies: calretinin (Zymed, 1:200), epithelial membrane antigen (EMA) (DAKO, 1:50), thrombomodulin (DAKO 1:5), CK7 (DAKO, 1:100), CK5-CK6 (DAKO, 1:10), BerEp4 (DAKO, 1:25), carcinoembryonic antigen (CEA) (DAKO, 1:10), and CK20 (DAKO, 1:100). The EnVision technique was used for all antibodies. Sections were reviewed independently by three pathologists. Electron microscopy was performed on selected cases. In all cases, the morphologic light microscopy criteria for a diagnosis of malignant mesothelioma were present. However, two tumors were later excluded from the study because of diffuse strong positive immunostaining with CK20 and BerEp4 and an ultrastructural appearance of adenocarcinoma. Of the remaining cases, 15 of 18 (83%) were purely epithelioid in type, showing a mixture of papillary, tubular, and solid patterns, and 3 of 18 (17%) showed a mixed sarcomatoid/epithelioid pattern. All cases were positive for calretinin and EMA (100%), 16 of 18 (89%) were positive for thrombomodulin, and 15 of 18 (83%) were positive for CK7. CK5-CK6 positivity was present in 13 of 18 (72%) but varied in strength and distribution; 2 of 18 (11%) were positive for BerEp4. All the cases were negative for CK20 and CEA. Four of the 18 cases were examined by electron microscopy, which revealed long thin microvilli supporting a diagnosis of malignant mesothelioma. This study has shown that the immunocytochemical profile of testicular malignant mesotheliomas is similar to those arising in the pleura, with diffuse positivity for calretinin, EMA, thrombomodulin, and CK7, and negative for CK20 and CEA. Focal weak positivity may be encountered with BerEp4. However, histopathologists should be aware of the variability in CK5-6 staining in testicular specimens when compared with pleural mesotheliomas.

Nonpleural mesotheliomas: mesothelioma of the peritoneum, tunica vaginalis, and pericardium

Mesotheliomas are tumors that arise from the mesothelial cells of the pleura, peritoneum, pericardium, or tunica vaginalis. Although the number of new mesothelioma cases diagnosed each year in the United States seems to be leveling off or decreasing, several other countries are projected to have continued increased incidence of mesothelioma over the next several years. Of the approximately 2500 new cases of mesothelioma in the United States each year, most are pleural mesotheliomas. The peritoneum is the second most common site of mesothelioma development and accounts for approximately 10% to 20% of all mesotheliomas. Mesotheliomas that involve the pericardium or originate from the tunica vaginalis are rare tumors. Given the rarity of these tumors, it is difficult to obtain precise information regarding their incidence, natural history, and optimal management.

Well-differentiated papillary mesothelioma occurring in the tunica vaginalis of the testis with contralateral atypical mesothelial hyperplasia

Well-differentiated papillary mesothelioma (WDPM) occurs rarely in the paratesticular region, with only a handful of published case reports. Often presenting with recurrent hydrocele, WDPM is a multifocal mesothelial proliferation with a predominantly indolent clinical course. Accordingly, pathologic distinction of this lesion from true malignant mesothelioma is crucial, although it may be difficult because of the variability of associated histologic features. In addition, rare cases of WDPM have progressed to malignant mesothelioma, leading to its classification as a tumor of low malignant potential. Here, we report a case of multifocal WDPM occurring in the tunica vaginalis and tunica albuginea, with contralateral atypical mesothelial hyperplasia, a potentially premalignant lesion.

Cancer Incidence Among Members of the Norwegian Trade Union of Insulation Workers

Insulation work has been described as an occupation with high exposure to asbestos. A cohort of members of the Norwegian Trade Union of Insulation Workers (n = 1116), hired between 1930 and 1975, was established. During 2002, the cohort was linked to the Cancer Registry of Norway. The standardized incidence ratio (SIR) of pleural mesothelioma was 12.9 (95% confidence interval [CI] = 6.0-24.6). Two cases with peritoneal mesotheliomas were found (SIR, 14.8; 95% CI = 1.8-53.4). The SIR of lung cancer was 3.0 (95% CI = 2.3-3.8). Four cases of lung cancer were observed among cork workers without any exposure to asbestos, but to cork dust and tar smoke (SIR, 5.3; 95% CI = 1.5-13.6). Our study showed a high risk of mesothelioma and an elevated risk of lung cancer among members of the Trade Union of Insulation Workers.

Immunophenotypings of malignant epithelial mesothelioma and their roles in the differential diagnosis

To investigate the immunophenotypings of malignant epithelial mesothelioma (MEM), and to seek the valuable markers in distinguishing peritoneal MEM from peritoneal metastatic ovarian adenocarcinoma (OA) and colorectal adenocarcinoma (CA), immunohistochemical SP method was used to detect expressions of HBME-1, E-cadherin, CA19-9, MOC-31 and CK7 in paraffin-embedded tissues of 18 cases of MEM, 20 OA and 20 CA. The results showed that there was a significant difference in the expressions of E-cadherin, CA19-9 and MOC-31 between MEM and OA group (P<0.05). Similarly, the difference in the expression of HBME-1, E-cadherin, CA19-9, MOC-31 and CK7 between MEM and CA groups is significant (P<0.05). These results indicate that HBME-1 could be used as a positive marker in distinguishing MEM from CA. E-cadherin, CA19-9 and MOC-31 are considered to be useful negative markers in diagnostic distinction between MEM and metastatic adenocarcinomas, including OA and CA. CK7 is the best positive marker in distinguishing MEM from CA, but this marker appears to be valueless in discriminating MEM from OA.

Paratesticular mesothelial proliferations

Varied mesothelial proliferations are found around the testes. Benign reactive mesothelial proliferations in hydrocoeles may be very florid and histologically worrisome, but these can usually be separated from malignant mesotheliomas of the tunica vaginalis because they are confined to a sharply demarcated zone near the luminal surface. In addition, benign inflamed hydrocoeles tend to show a distinct zonation with cellular areas near the luminal surface and more fibrotic areas beneath. The proliferating mesothelial cells in benign reactions often form lines that are parallel to the surface of the hydrocoele. Malignant mesotheliomas of the tunica vaginalis are usually grossly visible as single or multiple nodules. Histologically, they show an epithelial- or mixed epithelial- and sarcomatous-morphologic image, with evidence of stromal invasion. Well-differentiated papillary mesotheliomas are usually solitary exophytic nodules with a distinctive morphologic appearance and benign course, but they must be carefully separated from malignant mesotheliomas with a focally exophytic papillary growth pattern. By definition, well-differentiated papillary mesotheliomas do not exhibit stromal invasion. Peritesticular adenomatoid tumors are also very common; they are benign circumscribed cellular nodules with an appearance comparable to that of adenomatoid tumors in other body locations such as the uterine serosa.

Localized malignant mesothelioma of the epithelial type occurring as a primary hepatic neoplasm: a case report with review of the literature

We report a localized malignant mesothelioma of the epithelial type, occurring as a primary hepatic neoplasm in a 64-year-old male. He was found to have a mass located in the right lobe of the liver. Surgery was carried out with resection of the mass from the right hepatic lobe, with partial resection of the diaphragm. Grossly, an ill-defined tumor was present in the hepatic parenchyma. Histologically, the tumor displayed a predominant tubular pattern of growth with a desmoplastic stroma. The tubules were lined by a single layer of cuboidal or flattened cells with pleomorphic vesicular nuclei. A hyaluronidase-digestible, mucin-like substance was demonstrated in the lumen and tumor cytoplasm. The tumor cells were immunohistochemically positive for calretinin, HBME-1, cytokeratin, i.e. AE1/AE3 and CAM 5.2, but negative for carcinoembryonic antigen, CD 34 and Leu M1. Moreover, the tumor cells showed nuclear accumulation of the p53 oncopotein and reacted frequently with Ki-67 antibody. These findings support the concept that malignant mesothelioma of the epithelial type may occur at extrapleural sites. To the best of our knowledge, this is the first reported case of localized malignant primary mesothelioma arising in the liver.

Malignant gonadal mesothelioma

Malignant mesothelioma of the gonads is a rare and highly lethal disease. Most of these tumors arise from the tunica vaginalis, which is a continuation of the mesothelium similar to the pleura and the peritoneum. However, intratesticular and ovarian mesotheliomas have also been described. Occasionally, patients with localized disease at the time of detection have been known to survive for more than 10 years; however, the majority will not live beyond 5 years, with median survival being approximately 23 months. The principle reasons for this are difficulty in making a preoperative diagnosis and advanced stage at the time of treatment. Surgery forms the mainstay of management for all stages of the tumor. Adjuvant therapy in the form of chemotherapy, immunotherapy, or radiotherapy has negligible benefit. It is essential to diagnose this rare entity at the early stages to allow complete surgical extirpation. For the management of localized disease, we suggest the following protocol: initial staging of suspected cases with computed tomographic scan of the abdomen and pelvis; radical inguinal orchiectomy or hemiscrotectomy; retroperitoneal lymph node dissection in cases with positive nodes on scan or biopsy; and inguinal node dissection in cases requiring hemiscrotectomy. For advanced or recurrent disease, we suggest local radical resection with chemotherapy, including high-dose cisplatin and doxorubicin for two cycles of 5 days each; add local radiotherapy for uncontrolled locally advanced disease.

p27(kip1) immunoreactivity correlates with long-term survival in pleural malignant mesothelioma

BACKGROUND

Pleural malignant mesothelioma (PMM) is a rare and highly aggressive tumor, whose development is strictly related to occupational exposure to asbestos. The prognosis of PMM is generally poor (median survival, 4-12 months), but a few have a relatively long survival. The objective of this study was to evaluate the use of the cell cycle-related proteins p27(kip1) and MIB-1 as prognostic indicators of survival in PMMs.

METHODS

Of 621 PMMs, the authors selected 27 cases with a relatively long-term survival (> 24 months) and a control group of 36 PMMs having a shorter (usual) survival (< 24 months).

RESULTS

The expression of the p27(kip1) was significantly higher in the long-term survival group compared with the control (short survival) group (81.41% vs. 31.94%; P < 0.0001). The PMMs of epithelioid histotype had a significantly higher p27(kip1) immunoreactivity compared with those of biphasic type (59.24% vs. 38.94%; P = 0.02). In agreement with the data in the literature, the proliferative activity (as detected by MIB-1 immunoreactivity) was significantly higher in short than long survival PMMs (43.53% vs. 14.11%; P < 0.0001) and in the biphasic histotype than in the epithelioid type (43.19% vs. 26.02%; P = 0.006).

CONCLUSIONS

The combined expression of high/low p27(kip1) and low/high Ki-67 values identified with 100% specificity and sensitivity long versus short survivors. p27(kip1) represents a reliable additional predictive factor for PMMs and a useful marker to identify patients having a more favorable prognosis.