it is a benign soft tissue tumor that can arise from almost any site within the genitourinary tract containing smooth muscles . the most common localization is the renal capsule , followed by the bladder wall , epididymis , spermatic cord and tunica albuginea ( chiaramonte , 1988 ) . most of them are unilateral , nevertheless some cases of bilateral tumors have been described ( chiaramonte , 1988 ; aus et al . , 1991 ; krichen makni et al . , we report a case of a patient with primary infertility who had testicular sperm extraction ( tese ) for intracytoplasmic sperm injection ( icsi ) and in whom a paratesticular mass was discovered accidentally during the tese procedure . a 31 years old man with a primary infertility of 7  years was referred to our center because of azoospermia . clinical examination revealed normally sized testes with a testicular volume of 15 ml as measured by a prader orchidometer . both epididymis and vasa deferentiae , were present at both sides . six months before , the couple underwent a first unsuccessful tese - icsi treatment in another clinic . routine laboratory examinations showed a serum follicle - stimulating hormone ( fsh ) of 11.8 iu / l , luteinizing hormone ( lh ) of 8.4iu / l and free testosterone of 56.6 ng / l . the wife of the patient had a regular menstrual cycle and the ovarian hyperstimulation was performed using a classical protocol with 0.25  mg / day of gonadotrophin releasing - hormone antagonist ( orgalutran , merck sharpe & dohme ) and 150iu / day of recombinant gonadotrophins ( gonal - f , merck serono ) . ovulation triggering was done with 10000  iu of human chorionic gonadotophin ( pregnyl , merck sharpe & dohme ) . oocyte pick - up was performed under general anesthesia 36 hours later and 8 mature oocytes were retrieved . the patient underwent a tese on the same day of the oocyte retrieval . during this surgery , an ovoid paratesticular mass was observed on the left testis , adjacent to the epididymis , measuring 2.5    2.5    2  cms . several testicular biopsies were taken to check the presence of spermatozoa and one of the biopsies was sending for pathological evaluation . the microscopic examination of the paratesticular mass revealed a tumour composed of interlacing fascicles of spindled smooth muscles ( fig . the immunohistochemistry for smooth muscle actin ( sma ) ( dako , clone 1a4 , dilution 1/100 ) was positive . the analysis of the testicular biopsy showed a complete germ cell aplasia ( sertoli - cell - only syndrome ) . however , after multiple tese , testicular spermatozoa were observed in the wet preparations which were used for icsi . based on morphology in the morning of day 3 after icsi ( van royen e , 1999 ) , 2 good quality embryos were transferred . testicular leiomyoma is a rare tumor of the testis ( chiaramonte , 1988 ; destito et al . , 1999 ) . it is found most commonly in white males between the fourth and sixth decades of their life with most presenting during the fifth decade ( aus et al . , 1991 ; leonhard et al . , 1993 ) . this differentiation is essential because of the high rate of malignancy in solid intratesticular lesions ( 90 - 95% ) ( doherty et al . , 1991 ; krone et al . , 1985 ; yilmaz et al . , the use of ultrasonography is extremely important to distinguish the two entities ( obrien et al . , 2008 ) ; it can differentiate between intra and extratesticular tumors in 95 - 100% of the cases ( 4 ) and avoid radical surgery . however , most of the patients have orchidectomy before a final diagnosis is established ( mcclellan et al . , 1986 ) . macroscopically , leiomyomas are greyish white masses with a rubbery consistency with whorled cut surface . microscopically , they are characterized by intersecting smooth muscle bundles , witch tend to be more prominent around the vessels and ducts . they may show myxoid characteristics and calcifications ( barton et al . , 1999 ) . necrosis , nuclear atypia and mitotic activity are unusual ( deluise et al . , 1976 ) . in 1996 , hertzberg et al . reported another feature of leiomyoma : multiple , narrow areas of shadowing not cast by calcifications , but corresponding to transition zones between the various tissue components of the mass and they suggested that it may help differentiate leiomyomas from other scrotal masses ( hertzberg et al . , 1996 ) . some authors support the theory of smooth muscle differentiation from myocytes in the wall of seminiferous tubules ( chiaramonte , 1988 ; longchampt et al . , 1998 ) . others authors proposed that they can arise from myoid cells or potentially their progenitors present in the vascular smooth muscle ( gonzlez et al . , 1999 ) . the final diagnosis of the leiomyoma is made on its histopathologic examination based on a cellular proliferation of band spindle cells having a typical morphology with cigar - shaped nuclei and eosinophilic cytoplasm ( obrien et al . , 2008 ) . the use of monoclonal antibodies ( clone i4a and hhf 35 ) reliably marks the product of  and  isoactin genes , thus detecting neoplastic cells of the smooth muscle origin ( brittingham et al . , 1997 ) . thereby , in 1999 , gonzlez et al , detected smooth muscle specific actin in the neoplastic cells using actin specific monoclonal antibodies ( gonzlez et al . the differential diagnosis of leiomyomas includes leiomyosarcoma , fibromas , adenomatoid tumors , cystadenomas , neurofibromatosis and specific inflammations ( deluise et al . , 1976 ; chiong et al . , , there was a successful sperm retrieval and icsi with an embryo transfer and ongoing pregnancy . there is little evidence that the presence of the tumor was of influence in the result of the tese because of its paratesticular localization . the foreign body inflammation with giant cells can be attributed to the prior tese procedure . in view of the pathologic findings and the extratesticular localization , further follow - up
leiomyomata of the urinary and male genital tract are extremely rare . 
 they have been reported throughout the genitourinary male tract and the most common localization is the renal capsule . 
 however , leiomyomas of the epididimis , spermatic cord , tunica albuginea and testis have been reported.we report diagnostic confirmation of a paratesticular leiomyoma in an azoospermic patient undergoing a testicular sperm extraction for intracytoplasmic sperm injection ( tese / icsi ) procedure .