Maldescensus testis is one of the most common congenital anomalies of the male urogenital tract. Physiological testicular descent is influenced by mechanical, genetic, and hormonal factors; consequently, the pathomechanism of undescended testis is considered multifactorial.

• Male urogenital tract • Maldescensus testis • Tunica vaginalis testis • Pathologies

Maroske L, Geiselmann D, Rodrian N, Streit K, Meyer TH (2026) Coincidence of Morgagni Hydatids and Undescended Testis: More Common Than Previously Thought? JSM Sexual Med 10(2): 1181.

Maldescensus testis is one of the most common congenital anomalies of the male urogenital tract. Physiological testicular descent is influenced by mechanical, genetic, and hormonal factors; consequently, the pathomechanism of undescended testis is considered multifactorial. Insufficient urogenital development can lead to accompanying pathologies, including the occurrence of a hydatid. This is often discovered incidentally during surgical treatment of testicular maldescensus.

A hydatid is a testicular appendage measuring 1 to 7 mm on average, located at the upper pole of the testicle as an appendix testis or in the area of the epididymis as an appendix epididymidis and covered by the tunica vaginalis testis (Figure 1).

Figure 1: Intraoperative finding of a hydatid during testicular relocation of an 8-year-old

Embryologically, it is a remnant of the Müllerian duct, which regresses in the male embryo under the influence of the anti-Müllerian hormone produced by Sertoli cells. A fluid-filled vesicle may remain. Because hydatids may undergo torsion and represent a leading cause of acute scrotum in childhood, the question arises regarding their prevalence in patients undergoing surgery for maldescensus testis.

The aim of the study was to analyze the prevalence of hydatids in maldescensus testis and to investigate possible correlations between the occurrence of hydatids, testicular location, and hydatid size depending on the patient’s age at the time of surgery.

This retrospective study was based on the analysis of digitized medical records of patients who underwent surgical treatment for unilateral or bilateral maldescensus testis at the Department of Pediatric Surgery – Pediatric Urology and Pediatric Traumatology, University hospital of Würzburg, between January 1, 2010 and December 31, 2015. A total of 610 procedures were performed on 814 testicles in 530 patients.

The statistical analysis was performed using Microsoft Excel for Windows 10. Descriptive statistics included median, mean, minimum, and maximum values. Graphical representations were created. Linear associations were assessed using the correlation coefficient.

During the 5-year observation period, 431 right-sided and 383 left-sided maldescensus testis were surgically treated. 67.55% of the procedures were unilateral, 32.45% bilateral. The tunica vaginalis was opened in 55.9% of right-sided cases (n = 241) and in 76.2% of left-sided cases (n = 292). When the tunica vaginalis was opened, a hydatid was detected in 72.6% of cases on the right and in 54.5% of cases on the left (Figure 2). This results in a total prevalence of 62.66% for opened tunica vaginalis, regardless of laterality.

Figure 2: Incidence of a Morgagni hydatid in the context of operative testicular relocation in our patient cohort (n = 814; study period: January 1, 2010 to December 31, 2015).

Among 334 positive hydatid findings, a total of 483 individual hydatids were identified, including 233 on the left side and 250 on the right side. A documented size measurement was available in 253 of 334 positive cases, corresponding to 75.75%, allowing correlation analysis.

Most hydatids measured between 0.2 and 0.4 cm, accounting for 66.9% on the left and 63.7% on the right. The minimum recorded size was 0.1 cm and the maximum 1.2 cm.

To evaluate the association between patient age and hydatid size, regression analysis was performed. The coefficient of determination R² was 0.27, indicating moderate predictive power for a linear relationship between age and hydatid size. The correlation coefficient r was 0.52. According to Cohen’s convention, this corresponds to a high correlation, indicating a significant positive correlation between patient age and hydatid size.

Hydatid prevalence was additionally analyzed according to intraoperative testicular position. Prevalence was 68.57% in retractile testes, 58.26% in gliding testes, 69.55% in inguinal testes, 64.89% in ectopic testes, and 45.83% in abdominal testes. Overall, no significant association between testicular location and hydatid prevalence was confirmed.

Intraoperative knowledge of associated pathologies is of significant clinical importance, as it can have a direct impact on the surgical procedure and long-term out-comes. Simultaneous therapeutic intervention may reduce the risk of future complications, such as torsion of a hydatid with subsequent infarction. Already in 1995, Miliaras et al., recommended removal of all testicular appendages during herniotomy, or-chidopexy, or hydrocele resection [1].

Adequate inspection of the testis and epididymis requires intraoperative opening of the tunica vaginalis. Comparing the data from our own study, in a total of 383 procedures on the left side, the tunica vaginalis was opened in 76.2% of cases [n=292], while in 23.8% [n=91] of cases, the tunica vaginalis remained closed. On the right side, the tunica vaginalis was opened in only 55.9% of cases [n=241] in a total of 431 procedures and remained closed in 190 procedures. If we now compare the number of hydatids detected when the tunica vaginalis was opened, positive evidence of a hydatid was found on the left side in 54.5% [n=159] of cases and on the right side in as many as 72.6% [n=175] of cases. Over time, an increasing rate of tunica vaginalis opening was observed, suggesting growing awareness of the clinical relevance of this finding. Based on these results, a more consistent opening of the tunica vaginalis during surgery for maldescensus testis should be recommended.

Previous studies have reported variable prevalence rates. In 2007, Józsa et al., presented research findings on the occurrence of hydatids [2].In relation to already descended testicles, the prevalence of hydatids was reported to be 76%. In cases of Maldescensus testis, however, this figure was only 24%. In 2013, Tostes et al.,found positive evidence of hydatids in 61.6% of cases in boys with undescended testicles with an average age of 6 years [3]. This was followed in 2017 by a study by Favorito et al., Of the total of 108 testicles operated on, 67 had a hydatid [4]. The prevalence rate was thus 62.04%. In the same year, Zvizdic et al., published a study that specifically addressed the function of hydatids on the testicles in the context of testicular descent. The overall prevalence in relation to all testicles examined was 67.71% [5]. In summary, based on the four studies available, the overall prevalence rates of hydatids in undescended testicles can be stated as 24% (Józsa et al. [2]), 61.6% (Tos-tes et al., [3] ), 62.04% (Favorito et al.; [4]) and 67.71% (Zvizdic et al., [5]).

With an overall prevalence rate of 62.66% within our own patient group, the results are comparable to those of Favorito and Zvizdic and can therefore be considered representative. While individual studies reported lower or higher prevalence rates, several studies found no consistent correlation between testicular location and the occurrence of hydatids. In the present cohort, no significant correlation between intraoperative testicular position and hydatid prevalence was observed. Although abdominal testicles showed a lower prevalence than more descended testicles, the differences were not sufficient overall to derive a clear statistical correlation.

Of notable importance is the first systematic evaluation of the relationship between patient age and hydatid size. The correlation coefficient of 0.52 indicates a significant positive association. Increasing patient age was associated with larger hydatid size. The coefficient of determination of 0.27 suggests that age represents a relevant, though not exclusive, influencing factor.

A potential pathophysiological explanation may lie in hormonal influence. Samnakay et al., demonstrated the presence of estrogen and androgen receptors within hydatid epithelium [6]. Klein et al., showed that both estrogen and androgen levels increase progressively during puberty [7]. In the presence of corresponding receptors, hormonal stimuli may induce growth promoting processes in hydatid tissue, thereby explaining the observed age-related size progression [6].

Hydatid torsion is the most common cause of acute scrotum in children and adolescents (approx. 50%). Since the incidence of testicular torsion (approx. 25% of the causes of acute scrotum) in the current literature is approx. 1:4,000 male patients, the incidence of epididymal torsion must therefore be approx. 1:2,000 boys. Hydatid torsion occurs most frequently in boys between the ages of 7 and 12 [8-11]. The cause can be assumed to be a connection between torsion and a progressive in-crease in hormones, accompanied by a progressive increase in the size of the existing hydatid during puberty. Sonographic normal values for the size of the hydatid are given as 1–7 mm; in the case of torsion, these values are higher [12].

The results of this study thus provide further evidence for a more comprehensive understanding of hydatids in the context of maldescensus testis. They highlight the need for further studies to systematically investigate the hormonal influence and possible causal relationships between size progression and torsion risk.

The overall prevalence of hydatids in opened undescended testes within the present cohort was 62.66%. As in previous studies, no significant correlation between hydatid prevalence and testicular location could be confirmed.

For the first time, a significant positive correlation between patient age and hydatid size was scientifically demonstrated, with a correlation coefficient of 0.52. This suggests age-dependent size progression, possibly under hormonal influence.

Based on these results, consistent opening of the tunica vaginalis during surgery for maldescensus testis, with inspection and removal of present hydatids when indicated, should be considered in order to reduce the risk of subsequent complications such as hydatid torsion.

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