Teaching Case

A 42-year-old man presented with progressive perineal pain, pain on ejaculation, dysuria and infertility.

CT examination without and with contrast administration on 64-slice system and the MPR and MIP reconstructions were performed.
MR imaging examination on 1.5 T system, coil dedicated, on the axial, coronal and sagittal planes, using FSE T1W, FSE T2W, STIR and MR hydrography sequences, were performed.
CT examination of pelvis shows large bilobed homogenous slightly hyperdense mass without contrast enhancement arising from right seminal vesicle posterior to bladder.
The CT also shows the ipsilateral renal agenesis.
MRI confirms the presence of the bilobed mass and T1-weighted image shows signal intensity greater than urine, suggestive of haemorrhage or increased protein content.
MRI hydrography shows the ipsilateral rudimentary ureter.

Seminal vesicle cyst associated with upper urinary tract malformations is an extremely rare disease [1].
Seminal vesicle cysts are of congenital or acquired origin. Most of them have a congenital cause, which is believed to be secondary to obstruction of the ejaculatory duct. It is associated with anomalies of maldevelopment of the distal portion of the mesonephric duct, such as renal dysplasia, renal agenesis, and ectopic ureter [2]. Ipsilateral renal agenesis was first described by Zinner. Seminal vesicle cysts are usually asymptomatic. However, the cyst can grow and induce compression of neighboring organs (bladder), inflammation and irritating symptoms, including urinary frequency and dysuria, suprapubic pain, haematospermia, painful ejaculation. Moreover it can also cause infertility [3].
Several imaging techniques have been used in the evaluation and differentiation of pelvic cystic masses. US findings can confirm the cystic nature of the pelvic masses, determine the relative size and location [4]. CT can accurately show renal anomalies and define pelvic anatomy. On CT images the cysts may be seen as well-defined, low attenuation or slightly hyperdense lesions [5]. The multi-planarity of MRI allows to define abdominal and pelvic anatomy and to differentiate cystic malformations of the pelvis, which makes it the ideal imaging study. The usual appearance of a seminal vesicle cyst is that of a lesion with low T1-weighted and high T2- weighted signal intensity. However, seminal vesicle cysts may show increased T1-weighted and T2-weighted signal intensity, thought to reflect increased concentration of proteinaceous material or haemorrhage [6].
Treatment of the seminal vesicle cyst can be decided according to symptom existence. When surgical treatment for symptomatic seminal vesicle cyst is necessary, the conventional surgery is frankly invasive because of the deep location and dissection difficulty of the seminal vesicles in the retrovesical space [9]. Recently, the laparoscopic approach has been advocated as an optimal minimally invasive technique for the surgical treatment of seminal vesicle pathology [7]. Diagnostic techniques provide a fundamental contribution for surgical planning. In particular MRI is a powerful tool for detecting seminal vesicle cysts and in delineating associated congenital anomalies of the urogenital tract [8, 9].