蔡承翰¹、吳宏豪^1,2,3、林登龍^1,2,3

台北榮民總醫院 泌尿部¹；國立陽明大學醫學院 泌尿學科²書田泌尿科學研究中心³

Cheng-Han, Tsai¹, Hung-Hao Wu^1,2,3, Alex T-L Lin^1,2,3

Department of Urology, Taipei Veterans General Hospital¹; School of Medicine² and Shu-Tien Urological Institute³, National Yang-Ming University, Taiwan

 

Leiomyoma is a benign tumor that can originate from any anatomic location of smooth muscle. Leiomyoma of the scrotum is a rare entity. They arising from the subcutaneous tissue or dartos muscle. We present a case of solitary scrotal leiomyoma in a 90 years old male who presented with a painless, firm lump in left side of scrotum.

A 90 years old male patient had history of type 2 diabetes mellitus under regular medication. According to the patient, he experienced a mass at left scrotum for at least 10 years and came to our OPD for help. Physical examination revealed a single well-defined, soft to firm, nontender lump on anterior aspect of left scrotum measuring 1.5 × 1 × 1 cm in size. It had no palpable connection to the testis, epididymis or adjacent deeper tissues. The skin was normal without any ulceration or discharge. Both the testes were normal without any palpable inguinal lymph nodes. The lump was clinically diagnosed as fibroma. Without any contraindication, excisional biopsy were performed and sent for histopathological examination.

Gross examination showed a grey firm tissue, measuring 2.2 x 2 x 2 cm. Cut surface showed solid, grey white, homogenous character. The histopathological examination revealed a well-circumscribed tumor composed of interlacing bundles of neoplastic smooth muscle cells with moderate cellularity and rare mitotic figures. Immunostain for h-caldesmon was positive. A final histopathological diagnosis of scrotal leiomyoma was rendered.

Leiomyomas may originate from any anatomic location of smooth muscle in the genitourinary system. Scrotal wall leiomyomas are rare and usually asymptomatic. Siegel and Gaffey demonstrated the rarity of this tumor finding only 11 cases in a review of 11000 cases of scrotal tumor. Due to their painless and slow growing nature, the patients usually present late with an average of 7.6 years between the patients recognition of the tumor and its surgical removal. Their recurrence and malignant transformation have

been described. Scrotal smooth muscle tumors can further be categorized as leiomyoma, atypical leiomyoma and leiomyosarcoma. Four pathological features are used to grade the scrotal smooth muscle tumors that include (i) size ≥5 cm in greatest dimension; (ii) infiltrating margin; (iii) ≥5 mitotic figures per 10 high-power field and (IV) moderate cytological atypia. Tumors with only one of the above-mentioned features are considered benign and those fulfilling two of the criteria are diagnosed as atypical leiomyomas while tumors showing three to four of these criteria are leiomyosarcomas. This case presentation highlights the characteristics of the scrotal smooth muscle tumors. Pathologists and clinicians should be avoid the possibility of erroneous diagnosis and treatment.