副睪丸平滑肌瘤: 病例和文獻回顧

詹凱勝¹、許軒豪¹、劉鐘琪¹、李良明^1,2、溫玉清^1,2*

臺北醫學大學市立萬芳醫院泌尿科

臺北醫學大學醫學系

Kai-Sheng Chan, Syuan-Hao Syu, Chung-Chi Liu, Liang-Ming Lee, Yu-Ching Wen

1. Department of Urology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan

2. Department of Urology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan

 

We report the case of a 55-year-old male patient who presented with an enlarged intrascrotal mass lesion for 1 month with no history of genital trauma or infection. On physical examination, a firm nodular mass of nearly 3 cm was palpated near the inferior portion of the left epididymis, and ultrasound images showed a whorl-like pattern of the left epididymis. Left epididymectomy was performed and pathology report revealing diagnosis of leiomyoma. The leiomyoma was determined to be a benign paratesticular lesion. No tumor recurrence was found during 6 years of follow-up.

 

Primary solid neoplasms of the epididymis are rare. The reported prevalence of these neoplasms varies between 3% to 16% of all patients referred for scrotal ultrasonography (US). Most paratesticular lesions are benign, asymptomatic and slow growing; however, it is important to note that 20% of these lesions are malignant. Adenomatoid tumors (73%) are the most common tumors of the epididymis, followed by leiomyomas (11%) and papillary cystadenomas (9%). Leiomyomas are benign tumors that are embryologically derived from mesenchymal cells. Leiomyomas can originate from any structure containing smooth muscle; however, they are rarely found in the genitourinary tract. Here, we report another case of a leiomyoma of the epidiymis.

 

A 55-year-old male without prior traumatic history noticed an enlargement of a left intrascrotal nodular mass for 1 month. Complain of soreness in the left scrotum was also noted. Physical examination showed a 3cm nodular mass lesion located in the inferior portion of the left epididymis. Scrotal US revealed a 2.6 x 2.6-cm mass of heterogenous echogenicity in the inferior portion of the left epididymis. The mass displayed a whorl-like pattern without internal calcifications. After discussion with the patient, left epididymectomy was performed. Pathologic finding revealed well-defined tumor with white and elastic gross appearance. Microscopically, the tumor was composed of intercalated smooth muscle bundles without necrosis, hemorrhage, cellular atypia or increased mitosis. The final pathologic diagnosis was a leiomyoma of the left epididymis. No tumor recurrence was found during 6 years of follow-up.

 

Among benign epididymal tumors, leiomyomas, developed from smooth muscle cells, are the second most common type. In the Western literature, leiomyomas account for 6% of cases, although the rate is higher (nearly 40%) in Asians. Patient ages range from the fourth to ninth decades of life, with the most common time of presentation being in the fifth decade; however, leiomyomas have also been reported in children. Leiomyomas develop on the right and left sides with roughly equal frequency. Bilateral lesions are rare; however, they do occur. In our case, the patient’s age was within the most common presentation time, and the leiomyoma developed only on the left-sided epididymis.

A scrotal mass of an indeterminate nature is the usual clinical presentation. A thorough history and physical examination are needed. Extratesticular scrotal masses are usually due to trauma, infection or inflammation and are of benign or malignant origin. The differential diagnosis for malignant tumors includes sarcomas, carcinomas, lymphomas, metastatic tumors and rhabdomyosarcomas. In the differential diagnosis, benign masses include adenomatoid tumor, fibromas, leiomyomas and papillary cystadenomas. In 1968, Brother et al. reviewed the literature and found 209 tumors of benign origin (75%) among 278 reported cases of epididymal tumors. Adenomatoid tumors were the most common, and the second most common from were leiomyomas, as presented in our case.

Scrotal US is usually performed, although it is difficult to identify the malignant potential based on US images. With US, epididymal leiomyomas usually appear solid, hypoechoic or heterogenous and can contain shadowing calcifications. Two types of images are described: the first image type is characterized by linear acoustic shadows that are not due to calcifications and that correspond to transition zones in the mass; the other image type appears as a whorl-shaped pattern that is also observed histopathologically, as in our present case. When doubt persists, magnetic resonance image can be used to provide additional data. Akbar eta al. attempted multimodality imaging of paratesticular neoplasms. However, further specific data are still needed to help refine the diagnosis, including the tumor location, morphologic features and tissue characteristics.

As radiographic imaging alone is insufficient to determine whether a tumor is malignant, surgical exploration is often advised. Treatment consists of orchiectomy, epididymectomy or surgical excision of the tumor. Such treatments can sometimes be overaggressive. Testis-sparing procedures can be considered for benign lesions; however, radical procedures may be necessary when a malignancy cannot be excluded. Resection of either the testis or epididymis will increase the risk of infertility, which must be addressed preoperatively so that sperm banking can be performed to ensure future fertility. Even in patients unconcerned with fertility, testis-sparing procedures should still be performed to preserve testicular hormonal function. Therefore, an intraoperative frozen-section analysis can be used to help decide whether testis-preserving procedures should be attempted. In general, an intraoperative frozen-section analysis of testicular tumors correlates extremely well with the final pathology.

Block and Block reviewed 17 cases and reported a mean age of 51 years when presenting with a painless mass of unknown duration with no recurrence after treatment. Carorla et al. also mentioned that no reports showed recurrence or malignant changes. In our case, an epididymectomy was successfully performed with no recurrence during 6 years of follow-up.

Paratesticular tumors are usually benign. Scrotal US can sometimes provide indications of the nature of the tumor, as in our present case. Surgical exploration is advised due to a 20% possibility of malignancy. Intraoperative frozen-section analysis can assist in decision-making regarding testis-sparing procedures that could preserve fertility and hormone function. Here, we added another case of primary leiomyoma of the epididymis to the existing literature.