Malignant mesothelioma of the tunica vaginalis testis related to recent asbestos



This article is corrected by:

  1. Errata: Erratum Volume 15, Issue 8, 755, Article first published online: 10 August 2008

Yosuke Ikegami, Department of Nephro-urology, University Graduate School of Medical Sciences, 1 Kawasumi Mizuhocho, Mizuho-ku, Nagoya 467-8601, Japan. Email:


Abstract:  We report an extremely rare case of malignant mesothelioma in the tunica vaginalis testis. A 67-year-old man was referred to our hospital complaining of painless swelling in the right scrotum. Ultrasonography and computed tomography demonstrated a mass of approximately 6 cm in the right scrotum. He underwent tumor resection under a diagnosis of right intrascrotal tumor. The histopathological diagnosis was malignant mesothelioma, and he died 26 months later from multiple metastases. Asbestos may be a significant contributor to malignant mesothelioma in Japan. There have been 46 cases reported in urology departments in this country of the related symptoms, but only two of these have been clearly attributable to asbestos, which may be due to the investigations being insufficient to obtain a definitive diagnosis. In addition, this symptom is often diagnosed preoperatively as hydrocele testis; it is therefore important to carry out ultrasonography when a hydrocele testis has been diagnosed.


Malignant mesothelioma is a malignant tumor that occurs most frequently in the pleural, peritoneal, and pericardial testis. Malignant mesothelioma of the tunica vaginalis testis is present in 0.3–5.0% of cases of malignant mesothelioma.1,2 Asbestos exposure has been implicated as a risk factor for these tumors.3 We report here a patient with malignant mesothelioma of the tunica vaginalis testis, and discuss the 46 cases reported by Japanese urologists.

Case report

A 67-year-old man was referred to our hospital in August 2002 with painless swelling in the right scrotum, which was suspected as a right testicular tumor. Physical examination revealed a tumor that was elastic, hard, and non-tender, with a nodular surface. Ultrasonography and computed tomography (Fig. 1) demonstrated a mass of approximately 6 cm with an enhanced area in the right scrotum. There was no evidence of distant or lymph node metastases. In addition, we did not recognize any abnormality such as asbestos lungs. Testicular tumor makers (human chorionic gonadotropin-β and α-fetoprotein) were within normal limits, and the patient had no history of asbestos exposure or testicular trauma. His occupation was painting.

Figure 1.

A tumor with skin and border indistinctness in the right scrotum with a region of strong contrast, as revealed by enhanced computed tomography.

After admission, we carried out tumor resection under a diagnosis of right intrascrotal tumor. The tumor adhered strongly to the scrotum skin, so we removed it surgically as a single lump with some scrotum skin, and the spermatic cord was removed surgically at the height of the inner inguinal ring (Fig. 2). Macroscopically, the tumor consisted of a hard and yellow nodule. The normal spermary organization was not recognized macroscopically.

Figure 2.

The extracted tumor adhered strongly to the scrotum skin, and its contents were predominantly yellowish white.

For histopathology, we determined the cutoff for the increase in staining associated with an atypical epithelium cell, which identified a variant mesothelium-like cell in the stroma (Fig. 3). In addition, immunohistological stainings for alpha-fetoprotein, human chorionic gonadotropin, and carcinoembryonic antigen were negative, and those for vimentin and calretinin were positive (Fig. 3). We therefore diagnosed the tumor as a malignant mesothelioma of the tunica vaginalis testis. We did not undertake further treatment, because there were no other effective therapies for malignant mesothelioma.

Figure 3.

(A) An atypical epithelium cell that appeared as a hyperplasia in the shape of a parcel nest (HE, ×400). (B) A variant mesothelium cell present in the stroma (HE, ×400). (C, D) Positive immunohistological staining for (C) vimentin and (D) calretinin (×400).

Progressive liver metastasis was evident at 24 months post-operatively, which resulted in multiple organ failure and subsequent death at 26 months post-operatively.


Malignant mesothelioma originates from serosal cells of the pleural, peritoneal, pericardial, and tunica vaginalis testis. The etiology of mesothelioma is unknown, but asbestos exposure has been suggested as a risk factor for the development of these tumors.4 Asbestos is a heat-resistant material that exhibits superior durability and economy, and hence is still widely used as a construction material. However, the possible association between asbestos and malignancies such as mesotheliomas-related disease may eventually lead to full-scale prohibition of its use.

We found 46 case reports of malignant mesothelioma from urologists, including the first report of Eimoto in 1977,5 most of which have occurred in the scrotum. However, only two of these cases were attributed to asbestos exposure. Plas et al. reviewed 74 cases of mesothelioma of the tunica vaginalis testis from published reports in 1998,6 of which 34.2% had a history of asbestos exposure.

Diagnosing the etiology of this condition by asking the patient questions about asbestos exposure may be insufficient. Instead, both the occupational and environmental exposures should be investigated, such as by considering morbidity in inhabitants residing near contributing factories, and doctor checklists.

There have been 38 reported cases of malignant mesothelioma of the tunica vaginalis testis in Japan, of which 16 were diagnosed as hydrocele testis preoperatively. Plas et al. reported that the median survival period was 23 months, with a range of 2–64 months.6 Only two of the 110 reported cases of radical orchidectomy survived more than 5 years,7 which indicates that convalescence is very poor for this disease. Therefore, it is important to diagnose a malignant tumor as soon as possible, and then operate immediately. There is a report that ultrasonography is useful for a preoperative diagnosis,8 in which it is important not to overlook thickening of the tunica vaginalis and the presence of small nodes. Cytology of the puncture liquid is not effective, and since there is a danger of a limited partial recurrence, this procedure is not recommended.6

A correct diagnosis of malignant mesothelioma requires a detailed investigation that includes asking questions about asbestos exposure. In addition, ultrasonography should be used to examine a hydrocele testis. The recent increase in the importance of asbestos in malignancies should be considered by urologists when they carry out their everyday diagnoses and medical treatment.