Nodular fibrous proliferation (fibrous pseudotumour) of the tunica vaginalis testis. A light, electron microscopic and immunocytochemical study of a case and review of the literature

A case of nodular fibrous proliferation of the tunica vaginalis testis occurring in a 25-year-old male is described. Electron microscopy and immunocytochemical analysis confirm a fibroblastic origin. The histogenesis of the lesion is considered in the light of the findings and a review of the literature. It is concluded that the lesions known variously as 'fibrous pseudotumour' and 'reactive periorchitis' represent a fibroblastic overgrowth of the genito-urinary tract in response to trauma or infection. Nodular or diffuse fibrous proliferation of the testicular tunica vaginalis is suggested as a unifying terminology for this group of lesions.     

Immunohistological studies of fibrous pseudotumor of the testicular tunica vaginalis

A fibrous pseudotumor of the testis from a 46-year-old man was examined histologically and immunohistochemically. The tumor, situated in the tunica vaginalis, appeared as multiple round nodules up to 2 cm in diameter, and was composed largely of fibrous tissue with scanty inflammatory cell infiltration. Besides mesothelial cells covering part of the tumor, foci of piled-up cells were found among the fibrous tumor tissue. The cells in the foci were spindle and polygonal in shape, and contained oval nuclei. Immunohistochemically, these cells were positive for vimentin and keratin, but negative for CEA. Similar features have been found in pleural mesothelioma, supporting the concept that testicular fibrous pseudotumor could represent neoplastic growth of the mesothelium of the tunica vaginalis.     

Expression of Wilms tumor-1 protein and CD 138 in malignant mesothelioma of the tunica vaginalis

Malignant mesothelioma (MM) of the tunica vaginalis is a very rare tumor which can be difficult to diagnose histologically. We report an 83-year-old patient with MM of tunica vaginalis of the left testis. To the best of our knowledge, this is the first reported case of MM of the tunica vaginalis expressing Wilms tumor-1 protein, CD138, the expression of which could help in confirming the histopathological diagnosis and in targeting therapy.     

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

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

Immunohistological Studies of Fibrous Pseudotumor of the Testicular Tunica Vaginalis

A fibrous pseudotumor of the testis from a 46 year old man was examined histologically and immunohisto-chemically. The tumor, situated in the tunica vaginalis, appeared as multiple round nodules up to 2 cm in diameter, and was composed largely of fibrous tissue with scanty inflammatory cell infiltration. Besides mesothelial cells covering part of the tumor, foci of piled up cells were found among the fibrous tumor tissue. The cells in the foci were spindle and polygonal in shape, and contained oval nuclei. Immunohistochemically, these cells were positive for vimentin and keratin, but negative for CEA. Similar features have been found in pleural mesothelioma, supporting the concept that testicular fibrous pseudotumor could represent neoplastic growth of the mesothelium of the tunica vaginalis. Acta Pathol Jpn 39: 810813, 1989.     

Clear cell adenocarcinoma of the tunica vaginalis of the testis with an adjacent uterus-like tissue

Testicular and paratesticular neoplasms that resemble the common epithelial type of ovarian tumor are quite rare. Paratesticular clear cell carcinoma is very uncommon in the testis, with no reported cases of a tumor arising from the tunica vaginalis in the literature to our knowledge. The present case shows that it is highly malignant and metastatic. The differential diagnosis of the tumor was made after thorough clinical, pathological and immunohistochemical investigations, from the mesothelioma of the tunica vaginalis, paratesticular serous papillary carcinoma, carcinoma of the rete testis, epididymal adenocarcioma, yolk sac tumor of the testis and metastatic carcinoma. The tumor showed Bcl-2 and Her-2/neu immunoreactivity, but was non-reactive for p53. This tumor, with a uterus-like structure as a paratesticular tumor-like mass, was composed of endometrial-type glands and stroma surrounded by bundles of smooth muscle, and is the third example of this kind of structure in English written literature. The patient, having normal external genitalia and fertility, represents the first reported case of paratesticular malignant differentiation of müllerian-type epithelium in the normal gonadal state. Müllerian-type epithelium located in the vicinity of the testis and/or endometriotic metaplasia of the mesothelium of the tunica vaginalis might be the possible origins for this uterus-like structure, and as a result, for this tumor.     

Papillary serous carcinoma of the tunica vaginalis testis

This is a case report of a testicular papillary serous carcinoma of ovarian type (PSCOT) diagnosed in a 50-year-old man. The tumor presented in the form of multiple papillary exophytic excrescencies on the visceral tunica vaginalis testis lining the inner surface of a hydrocele sac. The tumor was histologically a papillary serous carcinoma with numerous psammoma bodies, indistinguishable from similar tumors arising on the surface of the ovary. Following the tumor's surgical removal, the patient was treated with the same drugs used to treat ovarian serous carcinomas, and he is alive two years after the initial diagnosis. PSCOT must be distinguished from mesothelioma of the tunica vaginalis testis, a tumor with a most unfavorable prognosis. As shown here, immunohistochemical findings can be useful for formulating the correct diagnosis of PSCOT.     

Malignant mesothelioma of the tunica vaginalis testis. Report of a case and review of the literature.

An autopsy case of malignant mesothelioma of the tunica vaginalis testis in a 60-year-old man is described. The tumor showed widespread metastasis via the lymphatics, leading to the patient's death five years after diagnosis. A review of 38 previously described cases is also presented. The most frequent presenting symptom was hydrocele. When a hydrocele in association with a paratesticular tumor is present, aspiration cytology should be performed first. In most of the cases with a fatal outcome, the tumors metastasized to the retroperitoneal lymph nodes. Once the diagnosis has been made, lymphangiography or CT scan should be done immediately.     

Malignant mesothelioma of the tunica vaginalis

A case of a malignant mesothelioma of the tunica vaginalis is presented. The patient with an intrascrotal mass was a 32-year-old Japanese male who had no history of asbestos exposure. The tumor was located on the surface of the right testis and was composed of columnar to polygonal cells with glandular and papillary structures. It showed many mitoses and focal invasion of the tunica albuginea. The tumor cells contained alcian blue- and Hale's colloidal iron-positive, hyaluronidase-digestible materials. Immunohistochemical stains for cytokeratin and vimentin were positive, while those for carcinoembryonic antigen, epithelial membrane antigen, Leu-M1, and factor VIII-related antigen were negative. The systemic examinations revealed no other tumors. Based on these findings the tumor was diagnosed as malignant mesothelioma of the tunica vaginalis. The differential diagnosis is discussed under the histologic, histochemical, and immunohistochemical points of view and the previous literature is reviewed.     

Malignant mesothelioma of the tunica vaginalis testis: a case with a predominant sarcomatous component

We present a case of malignant mesothelioma (MM) of the tunica vaginalis testis. A 64-year-old man was referred for an operation on a right hydrocele that later proved to be a tumor during surgery. The tumor was malignant with a biphasic pattern of epithelial and sarcomatous components. The latter component was predominant. Cuboidal or columnar cells formed irregular tubular structures in the epithelial component. In contrast, spindle-shaped or polygonal cells formed intricate structures with stromal connective tissues in the sarcomatous component. Immunohistochemical staining revealed that the tumor was mesothelial in origin and positive for cytokeratin, vimentin, HBME-1 antigen and calretinin. In general, MM occur in the pleura or peritoneum; those originating in the tunica vaginalis testis are very rare and represent less than 5% of all MM. In addition, MM in the tissues usually consist primarily of an epithelial component. According to previous reports tumors with a predominant sarcomatous component are extremely rare. In general, a sarcomatous component predicts poor prognosis and our case does, in fact, deteriorate over time. Our case suggests that despite its low incidence, MM must be considered when a case is diagnosed as hydrocele testicle.     

Mesothelial cells from tunica vaginalis, a practical source for mesothelial transplantation

Transplantation of mesothelial cells is used to repair peritoneum that is damaged by surgery, peritonitis, and peritoneal dialysis. The largest obstacle for clinical application of mesothelial cell transplantation is the lack of a reliable source of mesothelial cells. So far, they are isolated from omentum, mesentery, parietal wall and ascites. Procedures used to obtain mesothelial cells from the omentum or mesentery are invasive, however, especially in pre-operative situations. Sufficient amounts of ascites for aspiration can not be obtained under physiological conditions. We have developed a novel method of isolating mesothelial cells from the tunica vaginalis. The tunica vaginalis originates from the peritoneum and descends into the scrotum along with the testis during fetal development. This region provides a source of mesothelial cells that is convenient to approach and free from abdominal complications. Transplantation of autologous mesothelial cells that were isolated from tunica vaginalis was effective in preventing post-operative adhesions. In this review, we summarize mesothelial cell transplantation trials and describe the method of isolating mesothelial cells form the tunica vaginalis. Mesothelial cell transplantation might be widely accepted for clinical use in the near future.     

Benign papillary mesothelioma of the tunica vaginalis testis

We report a case of benign mesothelioma of the tunica vaginalis testis in a 69-year-old man who presented with a 4-month history of scrotal swelling. A polypoid pedunculated nodule, 1.5 cm in diameter, was found near the head of the right epididymis. Histologically, the tumor exhibited features characteristic of a well-differentiated papillary mesothelioma. The mesothelial origin of this tumor was further supported by immunohistochemical analysis. The tumor cells exhibited nuclear p53 protein accumulation, despite the benign histologic findings and a 3-year uneventful follow-up after resection. A polymerase chain reaction analysis for simian virus 40 DNA was negative. The papillary configuration seen in this tumor is uncommon for this site, inasmuch as benign mesotheliomas of the tunica vaginalis testis usually exhibit an adenomatous pattern. One should be aware of this pattern, and benignity should be mentioned in the pathologic report to prevent overtreatment. In addition, positive p53 immunohistochemical staining should not be taken automatically as evidence for malignancy in this type of lesion.     

Malignant Mesothelioma of the Tunica Vaginalis Testis Report of a Case and Review of the Literature

An autopsy case of malignant mesothelioma of the tunica vaginalis testis in a 60-year-old man is described. The tumor showed widespread metastasis via the lymphatics, leading to the patient's death five years after diagnosis. A review of 38 previously described cases is also presented. The most frequent presenting symptom was hydrocele. When a hydrocele in association with a paratesticular tumor is present, aspiration cytology should be performed first. In most of the cases with a fatal outcome, the tumors metastasized to the retroperitoneal lymph nodes. Once the diagnosis has been made, lymphangiography or CT scan should be done immediately.     

Mesothelioma of the tunica vaginalis testis with prominent adenomatoid features: a case report

Malignant mesotheliomas of the testis arise from the tunica vaginalis, formed from the evagination of the abdominal peritoneum into the scrotum. It is an extremely rare tumor representing 0.3% to 5% of all malignant mesotheliomas. We presented an interesting case of 68-year-old male with swelling and slightly painful in the right scrotum. Histologically, the lesion were composed of small tubular, microcystic, gland lined by flattened epithelioid cells and vague signet ring cells set in a myxofibrous stroma, which is resemblance to adenomatoid tumor. But the tumor cells showed significant atypical cytologic morphology and invaded into spermatic cord tissue, which indicated the diagnosis of malignant tumor. Immunohistochemistry study showed positive expression of CK, CK5/6, CK7, Calretinin, D2-40 and Vimentin which indicated the diagnosis of malignant mesothelioma. This case of mesothelioma should be classified as epithelial in type. To our knowledge, the mesothelioma of the tunica vaginalis testis with adenomatoid tumor-like microscopic features is very rare.     

Nodular and diffuse fibrous proliferation of tunica vaginalis--a case report

A case of nodular and diffuse fibrous proliferation (NDFP) of the tunica vaginalis testis occurring in a 40 year male is described. Immunohistochemistry confirmed fibroblastic origin. Histogenesis & differential diagnosis of this lesion is considered. Simple excision of this lesion is curative. The lesion is very rare but it is important that both surgeons & pathologists become aware of this entity to avoid radical orchiectomy in young patients.     

Epididymal rhabdomyoma: report of a case, including histologic and immunohistochemical findings

Genital rhabdomyoma is a rare tumor of skeletal muscle origin that is usually found in the vulvar area of young women. The English literature contains only 2 previous case reports involving men, both of whom were 19 years old. One of these lesions originated in the tunica vaginalis of the testis, and the other originated in the prostate gland. We present the clinical, histologic, and immunohistochemical findings of an epididymal rhabdomyoma in a 20-year-old man. To our knowledge, this is the first such case reported in this location.     

Origin and distribution of potassium bromate-induced testicular and peritoneal mesotheliomas in rats

Tissue sections were examined from a 2-year bioassay of male Fischer 344 rats treated with potassium bromate administered in drinking water. All animals exhibiting peritoneal mesotheliomas also had mesotheliomas of the tunica vaginalis testis mesorchium (the reverse was not true), and the correlation of these 2 types of mesotheliomas was highly significant (r2 = 0.98). Mapping of the tunica vaginalis tumors at all time points and at all bromate concentrations revealed a pattern of increasing incidence of tumor formation on the mesothelium of the tunica vaginalis testis as a function of proximity to the mesorchial ligament. Thus, the mesorchium appears to be the major mesothelial target site for potassium bromate-mediated carcinogenesis. The frequency of occurrence of mesotheliomas by location was tunica vaginalis testis (25%), mesosplenium (20%), mesentery (10%), mesojejunum/mesocolon (8%), bladder (6.5%), mesogastrium (13%), liver serosa (5%), and kidney, small intestine, and rectum (1% each). A complete cross-section of the rat testis was prepared and used to construct a complete map of the mesothelium. Any attempt to determine the role of local dose and tissue susceptibility for the purpose of interspecies risk extrapolation must take into account the complex anatomy and physiology of this region of the visceral and testicular suspensory apparatus. Improved histologic approaches are needed for adequate assessment of this delicate suspensory system.     

Concomitant malignant mesothelioma of the pleura,peritoneum, and tunica vaginalis testis

We describe the cytohistological, immunohistochemical and ultrastructural findings in a 55-yr-old-man with history of asbestos exposure and diffuse malignant mesothelioma (DMM) of the pleura, peritoneum, and tunica vaginalis presenting with chest pain and scrotal swelling. Pleural fine-needle aspiration (FNA) revealed mesenchymal elements and spindle-shaped epithelial-like cells, while biopsy showed pure sarcomatous tumor invading lung parenchyma. In both samples tumor cells coexpressed cytokeratin and vimentin. Peritoneal and hydrocele effusions contained aggregates of malignant mesothelial cells. Electron microscopy showed intermediate filaments, rare desmosomes and sparse microvilli. Morphological findings were consistent with a DMM, with a biphasic pattern in the pleura and an epithelial one in the peritoneum and tunica vaginalis. Although the possibility of a multicentric origin cannot be ruled out, clinical chronologic sequence suggests that the pleura was the primary involved site, followed by spread to peritoneum and tunica vaginalis. Diagn Cytopathol 1996;14:243–248. © 1996 Wiley-Liss, Inc.     

Testicular and paratesticular tumors and tumor-like lesions of ovarian common epithelial and müllerian types. A report of four cases and review of the literature

Three new and eleven previously reported testicular or paratesticular tumors that resembled ovarian tumors of common epithelial type are discussed. The 14 tumors occurred in patients ages 11-68 (average 47) years of age. The exact location for 12 of the tumors is known; 5 involved primarily the testicular parenchyma, 3, the tunica vaginalis, and 4, paratesticular tissue. Five tumors were serous, four of which were in the borderline category. Four tumors were Brenner tumors, admixed in one case with an adenomatoid tumor. Single examples of mucinous cystadenoma, mucinous cystadenocarcinoma, endometrioid adenoacanthoma, clear cell adenocarcinoma, and a benign tumor of mixed cell types complete the list. Follow-up of from 3 months to 14 years is available in eight cases; only one tumor, the clear cell adenocarcinoma, is known to have been clinically malignant. A fourth lesion in this article was a paratesticular mass composed of endometrial glands and stroma and bundles of smooth muscle. It arose in an 82-year-old man who had been treated with estrogens for prostatic adenocarcinoma.     

Well differentiated (benign) papillary mesothelioma of the tunica vaginalis.

An unusual mesothelial lesion occurred in the tunica vaginalis of the testis. It conformed histologically and immunohistochemically to well differentiated papillary mesothelioma of the peritoneum. Its aetiology remains uncertain, but this lesion, more than likely, is innocuous. It is important to recognise this entity, which is not well documented in the tunica vaginalis, because it may be misdiagnosed as a malignant mesothelioma and the patient may be subjected to unnecessary treatment.