Testicular microlithiasis: Prevalence and tumor risk in a population referred for scrotal sonography

OBJECTIVE. Considerable accrued evidence points to an association between t esticular microlithiasis, intratubular germ cell neoplasia, and testicular tumor. This study assesses both the prevalence of testicular microlithiasis revealed on sonography in a referred population and the concurrent tumor r isk. MATERIALS AND METHODS. Over a 32-month period (April 1996 through November 1998), 4892 scrotal sonographic examinations were performed in 4819 patient s at four referral centers. All patients underwent high-resolution (7- to 1 0-MHz) imaging. Using a computerized word search (n = 4102; testicular micr olithiasis, calcification, microliths, calcific foci, tumor, neoplasm, canc er, hyperecho, hypoecho, heterogen, and carcinoma) and manual retrieval (n = 790), cases of tumor, testicular microlithiasis (>5 microliths per sonogr am), and testicular microlithiasis plus tumor were pulled and retrospective ly reviewed. The presence and type of tumor were confirmed at histology aft er orchidectomy. RESULTS. Fifty-four tumors were found among 4892 scrotal sonograms (28 semi nomas, 11 teratomas, 8 mixed germ cell tumors, 2 Leydig cell tumors, and 2 non-Hodgkin's lymphomas). Testicular microlithiasis was present in 33 patie nts, giving a prevalence of 0.68%. Concurrent tumor and testicular microlit hiasis were detected in seven patients, a relative risk of tumor in testicu lar microlithiasis was 21.6-foId (95% confidence limits: 10.6-fold, 44.2-fo ld). In one patient with testicular microlithiasis, a previous orchidectomy for mixed germ cell tumor had been performed (not included in the relative risk calculation). CONCLUSION. In a referred population of 4819 patients the prevalence of tes ticular microlithiasis: was 0.68% and the relative risk of concurrent tumor was 21.6-fold. Sonographic surveillance of testicular microlithiasis cases for tumor is mandatory.