Testicular microlithiasis: Prospective analysis of prevalence and associated tumor

PURPOSE: To evaluate testicular microlithiasis (TM) prospectively with modern state-of-the-art equipment. MATERIALS AND METHODS: Information concerning indication for examination, presence and degree of TM, presence of testicular tumor, and patient age was prospectively recorded for all patients referred for scrotal ultrasonography between 1996 and 1999. High-frequency linear transducers (7.5 MHz or higher) were used. TM was divided into classic (CTM) and limited (LTM) on the basis of the presence of five or more microliths on one or more images of the testes. Fisher exact tests were used for determining significant differences in proportions. RESULTS: Data in 1,079 patients were analyzed. The overall prevalence of TM was 18.1% (195 of 1,079). Forty (3.7%) patients had CTM, and 155 (14.4%) had LTM; 15 (1.4%) had tumors visible at US. Tumors were present in three (8%) of 40 patients with CTM (seminoma in two, embryonal cell in one), nine (5.8%) of 155 with LTM (seminoma in six, mixed germ cell in one, Leydig cell in two), and three (0.3%) of 884 with no TM (seminoma in two, other in one). There was no difference between CTM and LTM (P = .72) in the rate of coexisting tumor. There was a significant difference between no TM and CTM or LTM (P ≤ .001) in the rate of coexisting tumor. Eighty percent (12 of 15) of patients with tumor at presentation had CTM or LTM. CONCLUSION: Approximately one of 27 patients had CTM, and one of seven had LTM. Although a majority of patients with testicular tumors had coexistent TM, more than 90% with TM (both CTM and LTM) did not have tumor at presentation.