Ectopic Seminal Vesicle Masquerading as Thrombosed Varicocele in a Patient with Primary Infertility

To describe a rare congenital anomaly of an ectopic seminal vesicle presenting as a scrotal mass mimicking a thrombosed varicocele in a patient with primary infertility, and to highlight important diagnostic and embryological considerations.

We report a single-patient case study of a 36-year-old male evaluated for primary infertility and azoospermia. Clinical examination, laboratory investigations, semen analysis, scrotal ultrasonography, and pelvic magnetic resonance imaging (MRI) were performed. Surgical exploration was undertaken due to discordant clinical and radiological findings. Descriptive analysis was used, as this was an observational case report without statistical testing.

The patient presented with azoospermia, a normal hormonal profile, and bilateral palpable varicoceles on physical examination. Scrotal ultrasound demonstrated a 1.9 cm avascular para-epididymal hypoechoic mass suspicious for a thrombosed varicocele. Pelvic MRI showed bilateral atrophic seminal vesicles and a non-enhancing scrotal mass, also interpreted as consistent with thrombosed varicocele. Intraoperative exploration unexpectedly revealed an ectopic seminal vesicle within the scrotum, which was excised. This finding represents an exceedingly rare congenital anomaly arising from mesonephric (Wolffian) duct maldevelopment.

Ectopic seminal vesicles are extremely rare and may masquerade as common scrotal pathologies such as thrombosed varicocele, even on advanced imaging. In patients with azoospermia and suspected seminal vesicle anomalies, evaluation for associated renal abnormalities is essential due to shared embryologic origins. This case underscores the limitations of imaging alone and highlights the importance of maintaining a broad differential diagnosis and pursuing surgical exploration when clinical and radiologic findings are incongruent.