Polyorchidism: A Narrative Review on Clinical Manifestations, Diagnostic Challenges, Malignancy Risks, and...

Polyorchidism, the presence of more than two testes, remains the rarest congenital anomaly of the male gonads, with fewer than 300 histologically or radiologically confirmed cases reported worldwide. Most supernumerary testes are discovered incidentally during imaging or surgery, yet their detection raises critical questions about malignancy risk, reproductive potential, and appropriate management. Current evidence indicates that approximately 90% of patients have three testes and two‑thirds show left‑sided duplication. About 75% of supernumerary testes are scrotal, roughly one‑fifth lie in the inguinal canal, and a small minority are abdominal or retroperitoneal. Inguinal hernia, cryptorchidism, and torsion are the most frequent associated anomalies, whereas hydrocele, varicocele, and renal agenesis occur less often. The pooled risk of neoplastic transformation ranges from 1% to 7% overall but climbs to 15% to 20% when the supernumerary testis is undescended. High‑resolution ultrasound is the diagnostic mainstay, while magnetic resonance imaging is indispensable for extrascrotal lesions and for clarifying drainage patterns. Contemporary practice increasingly favors surveillance of scrotal, anatomically normal, vas‑draining supernumerary testes, whereas extrascrotal, non‑draining, dysgenetic, or radiologically suspicious lesions warrant orchiectomy. Fertility outcomes remain poorly characterized. Isolated reports document both preserved spermatogenesis and severe oligoasthenoteratozoospermia, and endocrine profiles are usually normal. Advances in imaging have enabled conservative, fertility‑preserving management in many patients, but the absence of prospective registries, standardized follow‑up protocols, and molecular profiling limits reliable risk stratification. Multicenter collaborations are therefore essential to refine oncologic estimates, clarify reproductive implications, and establish evidence‑based guidelines for this exceptionally rare condition.