LETTER TO THE EDITOR
Year : 2008 | Volume
: 25 | Issue : 2 | Page : 76--77
Cytological diagnosis of malignant mesothelioma of the tunica vaginalis of the testis
Gopi N Barui, Rupam Karmakar, Amitava Sinha, Aparna Bhattacharya
Department of Pathology, RG Kar Medical College, Kolkata, India
Gopi N Barui
Flat No - 507, Rail Vihar HSG CO-OP. Society, Kolkata - 700107
|How to cite this article:|
Barui GN, Karmakar R, Sinha A, Bhattacharya A. Cytological diagnosis of malignant mesothelioma of the tunica vaginalis of the testis.J Cytol 2008;25:76-77
|How to cite this URL:|
Barui GN, Karmakar R, Sinha A, Bhattacharya A. Cytological diagnosis of malignant mesothelioma of the tunica vaginalis of the testis. J Cytol [serial online] 2008 [cited 2020 Jul 2 ];25:76-77
Available from: http://www.jcytol.org/text.asp?2008/25/2/76/42457
To the Editor,
The most common primary malignant tumor of the tunica vaginalis is malignant mesothelioma, which is nearly always of a diffuse epithelial type and characterized by a combination of solid, papillary, and tubular foci.  It presents clinically as a swelling of the scrotum, often as hydrocele. It may locally invade the testis, epididymis, tunica, dartos, and the skin, and may metastasize to regional lymph nodes. We are hereby reporting a case that presented to the surgical outpatient department (OPD) with a right-sided paratesticular swelling along with mild hydrocele of three months' duration. Fine needle aspiration cytology (FNAC) showed cytological features that were suggestive of a malignant mesothelioma of the tunica vaginalis of the testis. Subsequent surgical biopsy showed histological features that were consistent with the cytological findings.
A 42 year-old male presented to the surgical OPD with a right-sided scrotal mass of three months' duration. Examination revealed a firm, nontender, paratesticular mass sized 3 ´ 2 cm in the upper pole of the testis along with mild hydrocele. FNAC demonstrated aspirates that were cellular, consisting of loose clusters of polygonal cells with dense cytoplasm, cytoplasmic processes, and central nuclei. Prominent intercellular gaps were evident in some clusters. Papillaroid structures of epithelial cells were also seen. There was no significant cytological atypia or increased mitotic activity. A cytological diagnosis of mesothelioma of the tunica vaginalis was suggested. Five months later, the patient attended the surgical OPD with a progressively enlarged swelling, 6 x 4 cm in size, in the right inguinoscrotal region. Repeat FNAC of the swelling was performed. The aspirates were bloody and markedly cellular [Figure 1]. Smears consisted of dispersed populations of polygonal cells with cellular and nuclear pleomorphism along with spindle-shaped cells. Increased mitotic activity and features of necrosis were evident in the smears. A cytological diagnosis of a malignant mesothelioma of the tunica vaginalis was rendered with suggestions of subsequent excision biopsy and histopathological examination. The right radical orchiectomy specimen showed a fleshy tumor, 7 x 5 x 3 cm in size, diffusely infiltrating the surrounding structures. The cut surface showed areas of hemorrhage and necrosis. Three enlarged inguinal lymph nodes were present within the specimen. Histopathological sections from the growth showed papillary and tubulo-papillary patterns of growth, having one or more layers of atypical mesothelial cells resting on fibrovascular cores. Focal stromal invasion was seen in places. A desmoplastic reaction was evident [Figure 2]. Sections from the lymph node showed metastatic deposits of tubulo-papillary structures. The final diagnosis rendered was of a malignant mesothelioma of the tunica vaginalis with metastasis in the inguinal lymph nodes.
Malignant mesothelioma of the tunica vaginalis is a very rare tumor as it is an unusual site of involvement. It usually presents clinically as hydrocele, with or without an associated mass, or as a paratesticular mass. When the clinical findings are consistent and there is a history of asbestos exposure, cytology can offer a clear-cut diagnosis of malignancy and supportive evidence of the tumor type. The first primary cytological diagnosis of a malignant mesothelioma of the tunica vaginalis of the testis was reported by Japko et al.  and Gorini et al .  They reported two cases of malignant mesothelioma of the tunica vaginalis of the testis, both with a history of asbestos exposure for more than ten years. One case was a purely epithelial type and the other case was biphasic. The full range of growth patterns of a malignant mesothelioma can be seen by using FNAC, including highly differentiated epithelial tumors as well as biphasic, sarcomatous and anaplastic forms. The most specific cytological pattern is a combination of sheets of cells, cell groups, dispersed polygonal cells with dense cytoplasm, epithelial cells, and spindle-shaped fibroblastic cells. Occasionally, a biphasic pattern is seen with both spindle cell and pure epithelial cell components. Eleven cases of malignant mesotheliomas of testicular tunica vaginalis were reported in the age range of 12 to 76 years by Jones et al .  Microscopic analysis revealed that five out of these 11 tumors were epithelial and six were biphasic with typical architectural and cytological features of a mesothelioma. Mixtures of papillary, tubular, and solid patterns predominated in the epithelial areas whereas interlacing fascicles of spindle-shaped cells with scanty stroma characterized the sarcomatous component. In our case, there was no definite history of asbestos exposure and cytological features were predominantly of the epithelial type with focal areas of the sarcomatous spindle cell component. Histopathological investigations also showed the biphasic nature of the tumor. Differentiating malignant mesothelioma of the monophasic, predominantly epithelial type from carcinoma of the rete testis is difficult and relies on the feature of the hilar location of the latter and also on immunocytochemistry. For better diagnosis, Koss et al .  recommended a panel of two positive markers - calretinine and cytokeratin 5/6, and two negative markers - EA and MOC-31. Based on all these reports, we can conclude that FNAC diagnosis is accepted as a basis for the diagnosis and management of malignant mesothelioma of the tunica vaginalis of the testis, particularly if material is available for immunocytochemistry.
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