睾丸鞘膜高分化乳头状间皮肿瘤1例

Well-differentiated papillary mesothelial tumour of the tunica vaginalis:A case report

间皮肿瘤起源于体腔内浆膜层表面的间皮细胞,常见于胸膜和腹膜,罕见于睾丸鞘膜[1]。根据2022年WHO《泌尿和男性生殖系统肿瘤分类(第5版)》,睾丸附属器官间皮肿瘤分为腺瘤样瘤、高分化乳头状间皮肿瘤(well-differentiated papillary mesothelial tumour,WDPMT)和恶性间皮瘤[2]。作为间皮肿瘤中极其罕见的类型,睾丸鞘膜WDPMT患者常无特异性临床表现和影像学特征,常因鞘膜积液、阴囊肿物、腹股沟疝等手术后意外发现[3]。

The mesothelium,which consists of a monolayer of mesothelial cells,extends over the surface of the serosal cavities(pleura,pericardium,peritoneum and tunica vaginalis).Mesothelial tumours of the tunica vaginalis is rare compared with those arise from pleura or peritoneum.According to World Health Organization 2022 Classification of Urinary and Male Genital Tumours(5th edition),mesothelial tumours of the tunica vaginalis were categorized into adenomatoid tumour,well-differentiated papillary mesothelial tumour(WDPMT)and mesothelioma.Since WDPMT of tunica vaginalis was rare,there was no consensus concerning the treatment of it.In this case report,a 29-year-old man who had endured intermittent right scrotal pain for 8 months,aggravating scrotal pain for 2 weeks was admitted.No symptoms,such as frequent,urgent,or painful urination were shown.Physical examination revealed the enlargement and tenderness of right scrotum,with no signs of lifting pain.The most recent scrotal ultrasonography before surgery revealed right hydrocele with maximum depth of 4 centimeters and poor blood flow of right testis.Under the circumstance of patient’s chronic history of testicular hydrocele,he underwent an emergency operation of right scrotal exploration and hydrocelectomy under epidural anesthesia.After opening the vagina tunic cavity,spot-like bleeding was observed on the right testicle,epididymis and vaginalis surface.The vaginalis was obviously thickened and the inner and outer walls were smooth.The post-operative histopathology revealed a grayish-brown tissue with a thickness of 0.3-0.5 cm,smooth inner and outer walls,and a suspected WDPMT with a diameter of 1.5 cm.Immunohistochemical staining showed positive for Calretinin,BAP1,WT-1,CK5/6,D2-40 and P16,which confirmed the diagnosis of WDPMT.To sum up,the purpose of this case report was to raise awareness of a rare disease WDPMT,which was usually asymptomatic and could be diagnosed by pathology and immunohistochemistry.The disease should be differentiated from testicular torsion,epididymitis,orchitis and oblique inguinal hernia in symptoms,and from malignant mesothelioma and adenomatoid tumour in pathology.Because of the rarity of the cases,there was no unified standard for the treatment of WDPMT at present.The common treatment methods reported in literature included orchidectomy and vaginectomy.Due to the lack of understanding of this disease,postoperative follow-up was still recommended for at least 5 years.