The Prevalence of Midline Prostatic Cysts and the Relationship Between Cyst Size and Semen Parameters Among Infertile and Fertile men

F. Lotti; G. Corona; A. Cocci; S. Cipriani; E. Baldi; S. Degl'Innocenti; P.N. Franco; M. Gacci; M. Maggi


Hum Reprod. 2018;33(11):2023-2034. 

In This Article

Abstract and Introduction


Study Question: When is the investigation and treatment of midline prostatic cysts (MPC) of clinical value in the work-up of males of infertile couples?

Summary Answer: With a prevalence of 10.2% in infertile men, MPC should be investigated according to a seminal algorithm detecting a MPC volume >0.117 ml, which may impair semen parameters, and could be treated to improve sperm count and achieve natural pregnancy.

What is Known Already: MPC are frequent and are considered a correctable cause of male infertility. However, they have been poorly investigated in an infertility setting. In addition, no study has investigated clinical and ultrasound (US) characteristics of men with MPC.

Study Design, Size, Duration: A cross-sectional analysis was carried out of 693 consecutive subjects consulting for couple infertility from September 2012 to March 2017. As a control group, 103 age-matched healthy, fertile men were studied. Furthermore, a longitudinal evaluation of 11 infertile men undergoing trans-rectal ultrasonically-guided cyst aspiration (TRUCA), semen analyses 1 and 3 months after TRUCA and a follow-up 1 year after TRUCA to assess natural pregnancy were performed.

Participants/Materials, Setting, Methods: All subjects underwent, in our outpatient clinic, clinical, hormonal, scrotal and transrectal US evaluation and semen analysis within the same day. Of 693 males of infertile couples, 648 (37.1 ± 7.9 years, mean+SD) without genetic abnormalities were studied, along with 103 fertile men (36.6 ± 5.0 years). Eleven infertile men underwent TRUCA and were followed-up as reported above.

Main Results and the Role of Chance: A MPC was present in 66/648 (10.2%) males of infertile couples and in 6/103 (5.8%) fertile men. MPC occurrence and volume were higher in patients with severe oligo- or azoospermia than in fertile men (all P < 0.05). Infertile men with a MPC showed a lower seminal volume and sperm count and a higher prevalence of azoospermia than the rest of the infertile sample or fertile men, and a higher frequency of US signs suggestive of ejaculatory duct obstruction. MPC volume was negatively associated with total sperm count (r = –0.452, P < 0.0001). In fertile men, the highest MPC volume was 0.117 ml, suggesting it as a biological threshold not compromising semen quality. In infertile men, using receiver operating characteristic curve analyses, a MPC volume >0.117 ml identified subjects with severe oligo- or azoospermia with an overall accuracy of ~75% (both P < 0.005). Eleven men with infertility, semen abnormalities and large MPC (>0.250 ml) underwent TRUCA, which led to sperm count improvement in all patients 1 month after surgery. Three months after TRUCA a lower sperm count and a higher MPC volume than 2 months before were observed (P < 0.005 and P < 0.05, respectively), although improved when compared to baseline. After TRUCA a natural pregnancy occurred in four couples. Finally, we propose an algorithm, based on semen parameters, useful in identifying a MPC in males of infertile couples.

Limitations, Reasons for Caution: Although in line with the sample size of previous studies (n = 7–20), the number of infertile men with MPC evaluated longitudinally after treatment is limited (n = 11). In addition, although a MPC volume >0.117 ml can negatively affect the sperm count, only MPC > 0.250 ml have been treated in this study.

Wider Implications of the Findings: First, the algorithm proposed is easy to use and useful for selecting patients who can benefit from a prostate US in the infertility work-up. Second, a MPC volume ≤0.117 ml may not impair semen quality, while a larger volume can lead to severe oligo- or azoospermia and could be treated. Third, TRUCA is effective, and simpler and less invasive than other surgical techniques for MPC treatment. Finally, since the MPC can increase in size and sperm count decrease over time after TRUCA, semen cryopreservation should be considered 1 month after TRUCA.

Study Funding/Competing Interest(S): Grants from the Ministry of University and Scientific Research (SIR project to F.L., protocol number: RBSI14LFMQ). No conflicts of interest.


Couple infertility, defined according to the World Health Organization (WHO, 2000), affects 4–17% of couples worldwide (Lotti and Maggi, 2018). A male factor is present in about half of cases, and a 'severe' male factor in one out of five infertile men (Punab et al., 2017). Severe oligo- and azoospermia represent the most severe male factors (Jungwirth et al., 2018).

The aetiology of male infertility can be classified as pre-testicular, testicular or post-testicular (Lotti and Maggi, 2018). Among post-testicular factors, midline prostatic cysts (MPC) are considered a correctable cause of male infertility (Jungwirth et al., 2018). MPC may cause partial or complete ejaculatory duct obstruction (EDO) (Lotti and Maggi, 2015). Complete EDO is associated with azoospermia and low semen volume. Partial EDO has a variable clinical presentation, including oligozoospermia with low or normal semen volume (Turek et al., 1996; Kadioglu et al., 2001). Previous studies have suggested seminal criteria and transrectal ultrasound (TRUS) signs (including midline or eccentric prostatic cysts; ejaculatory duct (ED) dilation or calcifications; seminal vesicles transverse diameter >15 mm) suggestive of EDO (Turek et al., 1996; Kadioglu et al., 2001). However, standard clinical diagnostic criteria of EDO are lacking (Paick et al., 2000; Donkol, 2010), and the European Association of Urology (EAU) guidelines do not report clear TRUS or seminal cut-offs indicative of EDO, especially for the partial form (Jungwirth et al., 2018). In the event of EDO associated with MPC, surgical treatment can lead to an improvement of semen parameters, and, in some cases, to natural pregnancy (Turek et al., 1996; Kadioglu et al., 2001). However, only two studies have investigated MPC prevalence in infertile men, reporting a high frequency (11%, Jarow, 1993; 17%, Kim et al., 1997).

Although MPC are relatively frequent in infertile men, they have been poorly investigated in an infertility setting. The aim of this study was to evaluate the MPC prevalence and characteristics in males of infertile and fertile couples, along with the identification of a critical MPC volume predicting an unfavourable semen quality. We also evaluated the outcome of MPC treatment in a small subgroup of males with couple infertility and semen abnormalities, using transrectal MPC aspiration. Finally, we propose an algorithm to identify which patients could be at risk of MPC in an infertility setting.