Dancing Megasperm: Ultrasound Sign of Epididymal Obstruction

The "dancing megasperm" sign—tiny moving echogenic foci in the epididymis on ultrasound—indicates epididymal obstruction, not just filariasis. Recognizing it prevents misdiagnosis.

• Tiny mobile echogenic foci in the epididymis on ultrasound represent the "dancing megasperm" sign, a classic teaching point.
• It signals epididymal obstruction from any cause (e.g., prior infection, vasectomy, congenital), not specific to filarial infection.
• Awareness of this subtle finding can avoid unnecessary evaluation for filariasis and guide appropriate management.

RadPigeon summaries are original and for information only. They are not clinical advice.