primary retroperitoneal germ cell tumors account for approximately 30% of extragonadal germ cell tumors ( egcts ) and for about 10% of all primary malignant retroperitoneal tumors . many studies have demonstrated an association between diffuse bilateral testicular microlithiasis ( tm ) and gonadal germ cell tumors and egcts [ 2 , 3 ] . nevertheless , it is still uncertain whether ultrasound surveillance is really necessary in patients with tm in the absence of other risk factors such as previous testicular cancer , a history of cryptorchidism or testicular atrophy . we report the cases of a 33- and a 39-year - old man presenting with a retroperitoneal extragonadal tumor and bilateral tm without a focal testicular mass . a 39-year - old man with a 6-month history of lumbar pain came to our hospital to perform an mri examination in order to rule out a lumbosacral hernia . the mri images showed no slipped disks , but we unfortunately detected a voluminous retroperitoneal solid mass . therefore , we decided to perform a total body ct to better characterize the mass and its relationship to adjacent structures . ct images showed a large heterogeneous retroperitoneal mass with curvilinear calcifications and a marked inhomogeneous enhancement after intravenous contrast medium injection due to the presence of necrotic - colliquative areas . this lesion displaced the left renal vein cranially , the abdominal aorta anteriorly and towards the right , and infiltrated the inferior vena cava , the left renal vein , and the left psoas muscle ( fig . 1 ) . the patient 's -fetoprotein , lactate dehydrogenase , and beta subunit of human chorionic gonadotropin levels were 2.680 iu / l ( normal , 90180 iu / l ) , 279 ng / ml ( normal , 07.5 ng / ml ) , and 4 miu / ml ( normal , < 5 miu / ml ) . we performed a scrotal ultrasonography ( us ) to rule out that this mass was a retroperitoneal metastasis of a primary testicular tumor : us showed bilateral classic tm ( defined as more than 5 calcifications scattered throughout the testicle ) , without a focal lesion ( fig . 2 ) . comparing the current ultrasound images with previous us testicular images ( the patient underwent a scrotal us when he was 25 years old because of a testicular trauma ) the patient underwent a ct - guided biopsy and at histology , an immature teratoma was diagnosed . a 33-year - old man came to our emergency department complaining of abdominal pain , vomiting , weight loss and mild jaundice . the patient 's serum -fetoprotein , lactate dehydrogenase , and beta subunit of human chorionic gonadotropin levels were 2.470 iu / l ( normal , 90180 iu / l ) , 232 ng / ml ( normal , 07.5 ng / ml ) and 3 miu / ml ( normal , < 5 miu / ml ) . besides , the serum markers of cholestasis were high : conjugated bilirubin was 2 mg/100 ml ( normal , < 0.2 mg/100 ml ) , -glutamyl transpeptidase 70 iu / l ( normal , 130 iu / l ) and alkaline phosphates 300 iu / l ( normal , < 170 iu / l ) . ct and mri examinations showed a giant retroperitoneal mass made up by multiple necrotic - colliquative fluid areas with a multilocular aspect , which dislocated the inferior vena cava anteriorly and with possible infiltrating signs ; it also compressed the portal vein and the common bile duct with moderate dilatation of the intrahepatic ducts ( fig . 3 ) . the patient was sent to do an us to rule out the presence of a primary testicular tumor , which revealed bilateral tm without a focal hypoechoic lesion ; the microcalcification pattern was quite similar to that of a past ultrasound exam that was performed when the patient was 22 years old because of a suspected varicocele . the patient underwent a ct - guided biopsy and at histology , a yolk sac tumor was diagnosed . an egct is by definition a germ cell neoplasm , displaying one of the histologic types associated with gonadal origin , but located outside the gonads . the most widely accepted theory suggests that egcts arise from primordial germ cells misplaced during their migration to the gonads . it remains uncertain , however , whether such tumors develop primarily at extragonadal sites or represent metastases of a primary testicular tumor . regarding the latter case , egct may have developed from  burned out testicular tumors or they may just be metastatic lesions from primary testicular tumors that were not detected at the time of the diagnosis . a burned out gonadal primary tumor is a regressed tumor which is seen as an echogenic scar or a hypoechoic tissue on testicular ultrasound and which clinically presents with metastasis . histologically , egcts comprise seminomas ( 3040% ) and nonseminomatous tumors ( 6070% ) in men and dysgerminomas and nondysgerminomas in women . nonseminomatous germ cell tumors ( nsgcts ) include teratoma , embryonal carcinoma , endodermal sinus tumor ( yolk sac tumor ) , choriocarcinoma , and tumors with mixed histology . -fetoprotein is produced by endodermal sinus tumors , either alone or in association with other types of germ cell tumors . these are useful serum markers in the diagnosis , prognosis , and follow - up of patients with germ cell tumors . the majority of the egcts occur in men , except benign mature teratoma , which occurs with equal frequency in men and women . egcts are usually seen in children or young adults , and typically arise in midline locations . in adults , the most common sites of primary egcts are , in descending order , the mediastinum , the retroperitoneum and the cranium . in children , primary retroperitoneal germ cell tumors account for about 10% of all primary malignant retroperitoneal tumors and about 3040% of egcts . egcts are often seen in or near the midline , especially between the t6 and s2 vertebrae . patients may present with metastases : brain , liver , lungs and bones are the common sites of metastases . seminoma is rare in the retroperitoneum and is seen as a large , lobulated , well - defined homogeneous solid mass with fibrous septa and ring - like or speckled calcifications . nsgcts are depicted as heterogeneous tumors with areas of hemorrhage , necrosis , and heterogeneous enhancement . flow voids as well as invasion of adjacent structures that are due to hypervascularity may be seen . primary testicular malignancy and egcts are often associated with tm [ 2 , 8 ] . this is an uncommon pathologic condition that is detected by scrotal us and is defined as the presence within the substance of the testis of 5 or more speckled bright foci , 12 mm in diameter , with little or no acoustic shadowing ; the microcalcifications usually affect both testes , but may be unilateral and can be focal or diffuse [ 3 , 4 ] . j. richenberg and n. brejt affirm that ultrasound surveillance is unlikely to benefit patients with tm in the absence of other risk factors ; on the contrary , in the presence of additional risk factors ( previous testicular cancer , a history of maldescent or testicular atrophy ) , patients are likely to be under clinical and ultrasound surveillance . nevertheless , it is still controversial whether performing sonographic surveillance is better than regular testicular self - examination in adult patients with classic tm and the absence of any known testicular tumor . in this setting , on the basis of our direct experience , we highlight the importance of annual ultrasonographic surveillance of the testis and retroperitoneal space in patients with occasionally detected tm . besides , taking into account the increased risk of metachronous testicular malignancy in patients with previous egct [ 6 , 9 ] , we recommend yearly testicular ultrasound follow - up after surgical removal of retroperitoneal gonadic tumor .
many studies have demonstrated an association between diffuse bilateral testicular microlithiasis ( tm ) and gonadal and extragonadal germ cell tumors . 
 nevertheless , it is still uncertain whether ultrasound surveillance is really necessary in patients with tm in the absence of other risk factors such as previous testicular cancer , a history of cryptorchidism or testicular atrophy . 
 we report the cases of a 33- and a 39-year - old man presenting with a retroperitoneal extragonadal tumor . 
 the first patient underwent an mri examination in order to rule out a lumbosacral hernia : mri images showed no slipped disks but a voluminous retroperitoneal solid mass . 
 the histological analysis revealed an immature teratoma . 
 the second patient came to the emergency department complaining of abdominal pain , vomiting , weight loss and mild jaundice : ultrasound examination showed a large , ill - defined heterogeneous abdominal mass , confirmed by ct and mri examination . 
 the histology diagnosed a yolk sac tumor . in both patients , 
 the testicular sonography was performed to rule out a focal lesion , but it displayed bilateral tm without a focal testicular mass . based on our direct experience , we highlight the importance of annual ultrasonographic surveillance of the testis and the retroperitoneal space in patients with occasionally detected tm .