Testicular microlithiasis predicts concurrent testicular germ cell tumors and intratubular germ cell neoplasia of unclassified type in adults: a meta-analysis and systematic review.

Background: There is an increasing body of literature associating testicular microlithiasis (TM), a common finding on testicular ultrasound, with testicular germ cell tumor (TGCT) and intratubular germ cell neoplasia of unclassified type (ITGCNU). Determining these associations is pertinent both clinically and biologically. To the authors' knowledge, no previous systematic review or meta-analysis has been performed.

Methods: A comprehensive systematic literature review was performed without language restrictions through July 2009 and included an exhaustive search of electronic databases and article references. Two reviewers extracted data independently. Studies were categorized according to the clinical context in which sonography was performed. The primary study outcomes were concurrent diagnoses of TGCT or ITGCNU, with TM. In addition, studies with prospective follow-up of patients with TM were reviewed.

Results: Thirty-three studies met inclusion criteria. TM was not associated with an increased risk of TGCT in asymptomatic men. However, in referral populations, TM was associated overall with a risk ratio of 8.5 (95% confidence interval [CI], 4.5-16.1; P<.001) for a concurrent diagnosis of TGCT and 10.5 (95% CI, 5.3-20.8; P<.0001) for ITGCNU. Seventeen observational studies were identified in which the interval development of TGCT in patients with TM was reported; however, the majority of those studies did not report the follow-up of a control arm and could not be summarized.

Conclusions: In the presence of risk factors, TM was associated with a substantially elevated risk of a concurrent diagnosis of TGCT and ITGCNU. The authors suggest modifications to recently proposed guidelines for the management of TM.