Diffuse testicular microlithiasis is associated with successful sperm retrieval in men with nonobstructive azoospermia.

OBJECTIVE: To evaluate whether ultrasonographic patterns of testicular microlithiasis are associated with sperm retrieval outcomes by microdissection testicular sperm extraction in men with nonobstructive azoospermia. DESIGN: Retrospective cohort study. SUBJECTS: A total of 975 men with histologically confirmed nonobstructive azoospermia who underwent microdissection testicular sperm extraction between July 2003 and September 2025 at two specialized male infertility clinics. EXPOSURE: Preoperative scrotal ultrasonography, with classification of testicular microlithiasis into four patterns: no microlithiasis, limited microlithiasis, classic microlithiasis, and diffuse microlithiasis characterized by a snowstorm appearance. MAIN OUTCOME MEASURES: Successful sperm retrieval by microdissection testicular sperm extraction. RESULTS: Diffuse testicular microlithiasis characterized by a snowstorm appearance (n = 6) was associated with uniformly successful sperm retrieval. In contrast, limited and classic forms of testicular microlithiasis showed no independent association with sperm retrieval outcomes. Histological parameters, particularly Johnsen's score, demonstrated the strongest association with successful sperm retrieval. CONCLUSIONS: Diffuse testicular microlithiasis with a snowstorm appearance was associated with uniformly successful sperm retrieval by microdissection testicular sperm extraction in men with nonobstructive azoospermia, suggesting preserved focal spermatogenesis in this subgroup.