Objectives: To investigate the relationship between microliths and germ cell tumor histologic subtypes and determine whether microliths correlate with tumor stage at diagnosis.
Methods: A total of 1249 patients with testicular cancer seen between 1999 and 2013 were evaluated; 346 of 1249 patients (28%) with primary testicular tumors and sonographic imaging of unaffected testicular tissue formed the analytic cohort. Age, ethnicity, tumor histologic subtype, and stage at diagnosis were extracted from the medical record. Two examiners concurrently recorded the highest number of microliths per image of unaffected testicular tissue.
Results: A total of 175 of 346 patients (51%) had 1 or more microliths; 69 of 346 (20%) had more than 5 microliths per image. The histologic percentage of seminomas positively correlated with the microlith count (rs = 0.12; P = .036); the histologic percentage of embryonal components negatively correlated with the microlith count (rs = -0.15; P = .007). A higher microlith count was associated with a lower stage at diagnosis (P = .0243). Subgroup analysis of pure seminomas suggested a trend toward a higher microlith count in patients with lower-stage disease at diagnosis (P= .07). No association was found between the tumor stage at diagnosis and microlith count in patients with greater than 50% embryonal components of tumors (P= .55). No association was found between microliths and age, tumor size, and presence of lymphovascular/rete testis invasion (P = .120, .500, .629, and .155, respectively).
Conclusions: Patients with testicular cancer who have microliths may be more likely to have a higher percentage of seminomas and a lower percentage of embryonal components in their primary tumors. Microliths also showed an association with earlier stages of disease at diagnosis.
Keywords: embryonal carcinoma; genitourinary ultrasound; microlithiasis; seminoma; testicular germ cell tumor; testicular sonography.
© 2015 by the American Institute of Ultrasound in Medicine.