[Diagnosis and treatment of malignant mesothelioma of the tunica vaginalis testis: a series of 7 cases].

Objective: To investigate the clinical features, diagnosis, prognosis of malignant mesothelioma of the tunica vaginalis testis (MMTVT). Methods: The clinicopathological data of 7 patients with MMTVT who treated at Sun Yat-sen University Cancer Center between January 2010 and October 2022 were retrospectively reviewed. Cases were first diagnosed at (M (IQR)) 49 (23) years old (range: 27 to 64 years old). The main clinical manifestations were scrotal enlargement (7 cases) and hydrocele (2 cases). Results: Three patients underwent radical orchiectomy as initial treatment, 2 cases underwent hydrocelectomy due to diagnosis of hydrocele, followed by radical orchiectomy at Sun Yat-sen University Cancer Center, and 2 cases underwent transscrotal orchiectomy. Common tumor markers of testicular cancer were not significantly elevated in MMTVT. The expression of tumor PD-L1 was positive in 2 out of the 3 cases. One patient received adjuvant chemotherapy and 2 patients received first-line chemotherapy after tumor recurrence. Chemotherapy regimens used include cisplatin+pemetrexed. Up to October 2022, 3 cases relapsed, of which 2 cases died. The median overall survival was 35 months (range: 4 to 87 months) and the median progression-free survival was 6 months (range: 2 to 87 months). Conclusions: MMTVT at early stage should be treated with early radical orchiectomy and followed up closely after surgery. The cisplatin+pemetrexed regimen is a common option for the treatment of metastatic MMTVT, while whether immune checkpoint inhibitors could serve as a second-line treatment option deserves further research.