Malignant mesothelioma of the tunica vaginalis testis is a rare, highly invasive urogenital malignant tumor with no specific clinical manifestations. Reported cases of this disease are limited. Therefore, an early preoperative diagnosis is difficult. The current study presents a case of malignant mesothelioma of the tunica vaginalis testis and a literature review. A 52-year-old man was admitted to Xiaoshan Affiliated Hospital of Wenzhou Medical University (Hangzhou, China) in December 2022 and underwent radical resection of the right testicle and epididymis but did not undergo radiotherapy or chemotherapy. The patient was followed up for 5 months, and no recurrence or metastasis was found. The rarity of testicular mesothelioma poses a challenge to its etiology and diagnosis, which is rarely achieved preoperatively. Malignant mesothelioma of the testicular tunica vaginalis has a poor prognosis and is not sensitive to radiotherapy or chemotherapy, requiring close postoperative follow-up. This condition is rare in clinical practice; therefore, it needs to be reported to aid clinicians' decision-making regarding diagnosis and treatment.