ORIGINAL RESEARCH n PEDIATRIC IMAGING Radiology: Volume 000: Number 0—   2017 n radiology.rsna.org 1 1 From the Department of Radiology (A.T.T., J.R.D.) and Divisions of Pathology (K.E.B.) and Biostatistics and Epidemiology (B.Z.), Cincinnati Children’s Hospital Medical Center, 3333 Burnet Ave, Cincinnati, OH 45229-3026; De- partments of Radiology (J.C.) and Urology (E.R.M.), Boston Children’s Hospital, Boston, Mass; Department of Radiology, The Children’s Hospital of Philadelphia, Philadelphia, Pa (K.D., R.R.G.); Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa (K.D.); Departments of Radiology (M.M.) and Pathology (M.J.H.), Texas Children’s Hospital, Houston, Tex; McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth), Houston, Tex (S.M.R.); Department of Diagnostic Imaging (O.M.N., M.T.B.) and Division of Pathology (G.R.S.), The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada (O.M.N., M.T.B.); Department of Pathology, Nemours/Alfred I. DuPont Hospital for Children, Orlando, Fla (K.R.C.); Department of Pathology, University of Michigan Health System, Ann Arbor, Mich (A.H.); and Department of Pathology, Baylor College of Medicine, Houston, Tex (M.J.H.). Received November 16, 2016; revision requested January 4, 2017; revision received March 10; accepted April 10; final version accepted April 27. Address correspondence to A.T.T. (e-mail: andrew. trout@cchmc.org). q RSNA, 2017 Purpose: To retrospectively define the strength of association be- tween testicular microlithiasis and testicular neoplasia in a large geographically diverse pediatric population. Materials and Methods: Retrospective review of scrotal ultrasonographic (US) ex- amination reports and pathology specimens obtained be- tween January 2000 and May 2014 at six academic pediat- ric hospitals in North America was performed. Reported cases were reviewed to confirm microlithiasis. Radiology and pathology data bases were searched for pathology- proven testicular tumors (benign or malignant germ cell or stromal tumors). Association strength (risk) was ex- pressed in terms of odds ratios (ORs) with and without adjustment for fixed study site effects based on logistic regression. Results: A total of 37 863 individuals underwent scrotal US during the study period. Mean age was 11.1 years 6 4.7 [stan- dard deviation] in boys with microlithiasis and 9.1 years 6 5.9 in boys without microlithiasis (P , .001). Microlithia- sis was confirmed in 2.90% of patients (1097 of 37 863; range, 1.61%–5.25% across sites). It was unilateral in 21.97% (241 of 1097) of patients and bilateral in 78.0% (856 of 1097). Tumor was identified in 4.64% (51 of 1097) of boys with microlithiasis and 0.33% (122 of 36 766) of boys without (unadjusted OR, 14.65; 95% confidence in- terval [CI]: 10.29, 20.84; adjusted OR, 14.19). Malignant germ cell tumors were identified in 2.8% (31 of 1097) of boys with microlithiasis and 0.12% (45 of 36 766) of boys without microlithiasis (unadjusted OR, 17.26; 95% CI: 11.8, 25.25; adjusted OR, 22.37). Sex cord–stromal tumors were identified in 0.46% (five of 1097) of boys with microlithiasis and 0.079% (29 of 36 766) of boys without (unadjusted OR, 5.8; 95% CI: 2.1, 16; adjusted OR, 6.39). Conclusion: There is a strong association between testicular microli- thiasis and primary testicular neoplasia in this pediatric population. q RSNA, 2017 Andrew T. Trout, MD Jeanne Chow, MD Erin R. McNamara, MD, MPH Kassa Darge, MD, PhD Raul Ramirez Grueso, MD Marthe Munden, MD Sarah M. Rothan, MD Oscar M. Navarro, MD Marta Tijerín Bueno, MD Kevin E. Bove, MD Kudakwashe R. Chikwava, MBChB Amer Heider, MD M. John Hicks, MD, DDS, PhD Gino R. Somers, MBBS Bin Zhang, PhD Jonathan R. Dillman, MD, MSc Association between Testicular Microlithiasis and Testicular Neoplasia: Large Multicenter Study in a Pediatric Population 1 This copy is for personal use only. To order printed copies, contact reprints@rsna.org