Bilateral Abdominal Cryptorchidism: A Case Study in Dog and Review of Its Relevant Consequences

¹Veterinary Consultant, Lifeline Veterinary Hospital and Research Center, Sanepa, Lalitpur, Nepal

²Assistant Professor, Institute of Agriculture and Animal Science (IAAS), Tribhuvan University, Nepal

*Corresponding author: Subash Rimal, Assistant Professor, Institute of Agriculture and Animal Science (IAAS), Tribhuvan University, Nepal, Phone: +977-9841119101; E-mail: [email protected]

Received Date: April 15, 2025

Published Date: May 30, 2025

Citation: Shrestha A, et al. (2025). Bilateral Abdominal Cryptorchidism: A Case Study in Dog and Review of Its Relevant Consequences. Mathews J Vet Sci. 9(5):78.

Copyrights: Shrestha A, et al. © (2025).

ABSTRACT

This report documents a dog's retained intra-abdominal testicle. An approximately eighteen-month-old male Golden Retriever was referred to Lifeline Vet Hospital and Research Center due to increased sexual activity. Physical examination of scrotum confirmed cryptorchidism. Initially, radiographic imaging did not locate position of retained testes, subsequently ultrasonography was performed to confirm the position of retained gonads. Blood work determined normal physiological parameters and midline exploratory laparotomy was performed under general anesthesia to remove retained testes. Post-operative care was done with parenteral antibiotics administration and wound management. The study focuses on diagnostic challenges of cryptorchid testes, significance of ultrasonography on diagnosis and early surgical intervention to prevent complications like testicular neoplasia, sertolima and hormonal imbalances.

Keywords: Retained Testes, Testicular Tumor, Laparotomy, Ultrasonography.

INTRODUCTION

Cryptorchidism is a condition when either of the testes does not descend into the scrotum, instead remains in the abdomen or inguinal region within the first eight weeks of life. It is observed in about ten percent of adult canines [1]. Abnormal abdominal translocation and transinguinal migration are caused by incomplete or non-existent testicular descent due to anomalies in the gubernaculum's outgrowth and regression or the presence of cranial gonadal suspensory ligaments [2]. There are typically three types of cryptorchid testicles: high abdominal, low abdominal, and inguinal [3,4]. In most cases of cryptorchidism, the testicle remains in the abdomen or the inguinal canal. However, one or both testicles may be found in the subcutaneous tissues of the groin region, which is located between the inguinal canal and the scrotum. Compared to a healthy testicle, a cryptorchid testicle is significantly smaller, and this syndrome is rarely accompanied by discomfort or other symptoms unless accompanied by problems like inflammation, trauma, or cancer [5].

While the precise etiology of cryptorchidism cause is unexplored; it is speculated to be associated with a sex-linked autosomal recessive trait defect that is prominent in certain breeds, such as Yorkshire terriers, Miniature Schnauzers, Pomeranians, Poodles, Shetland sheepdogs, and Chihuahuas [6]. Smaller breeds are 2.7 times more likely to be affected than larger breeds [4]. Palpation can often reveal the position of the retained testicle. However, an inguinal testicle could be confused for fat or the inguinal lymph nodes. Due to needless abdominal and inguinal investigation, an inaccurate testicle location can result in further problems for the patient [7]. If the testicles are intra-abdominal or too small to be detected by palpation, imaging through x-rays or ultrasound can be appropriate for diagnosis of cryptorchidism conditions [8].

CASE HISTORY

A one-eighteen-months-old male Golden Retriever weighing 26 kg was to showing excessive sexual desire and unusual protrusion of the penis was referred for regular neutering at Lifeline Veterinary Hospital and Research Center (LVH&RC), Sanepa, Lalitpur. Upon visual examination and palpation, the penis appeared normal with rudimentary scrotum, and absence of testes in the scrotal sac. Physical examination revealed pulse rate, heart rate, and respiration rate were 130/min, 132/min, and 48/min, respectively and a temperature of 100.5 degrees F. The dog displayed pink conjunctival mucous membrane and there was no sign of dehydration. Capillary refill time was 1.25 seconds.

Upon arriving at LVH&RC, the dog underwent a medical examination, including checking the genitals and palpating the scrotal sac with fingertips, which revealed the lack of testes. An X-ray of the abdominal and pelvic regions (lateral and Vento-Dorsal view) was performed, but it could not identify the retained testicles. Real-time B-mode ultrasonography using a trans-abdominal curvilinear probe of frequency ranging from 5-10 MHz was used to locate the retained testes (Figure 1). The dog was positioned in lateral recumbency and scanning was performed through the kidney's caudal border to the inguinal region, including the scrotal sac and urine bladder. The retained testes were identified by their echogenicity and texture with other abdominal organs. The dog was dorsally and laterally recumbent in the present case as the ultrasonography was taken.  Complete blood count, liver function test, renal function test, and blood glucose were assessed to evaluate underlying pathological conditions and assess the dog's proper physiology. All the blood profile revealed normal physiological condition of the dog (Table 1) and supporting the decision to perform surgical intervention under general anesthesia.

Figure 1. Ultrasonography Showing right testicles (Red Arrow) of cryptorchid dog.

Table 1. Blood parameters of cryptorchid dog including reference value

Based on diagnosis, a midline laparotomy was advocated to excise testes. The dog was off-fed for 12 hours before surgery. The premedication included 1mg/kg of Xylazine administered intramuscularly, ten minutes after receiving subcutaneous injections of atropine sulfate at 0.02mg/kg. Once an adequate level of sedation was achieved, a prophylactic dose of intravenous ceftriaxone at 15 mg/kg and meloxicam at 0.2 mg/kg were given 20 minutes before surgery. Once sedation was achieved, general anesthesia was induced using a mixture of diazepam and ketamine in a 1:1 ratio, administered @1ml/10kg. The surgery was performed using a caudal midline incision from the umbilicus to the cranial margin of the pubis. The major caudal organs were examined and found to be normal and both the testes were removed (Figure 2). A synthetic, absorbable, braided size two suture material (Catgut) was used to ligate the spermatic cord. The abdomen was closed in three layers according to standard procedures. Post-operative antibiotic and daily dressing of suture was done for five days.

Figure 2. Surgical removal of right testes (Yellow arrow).

DISCUSSION

Cryptorchidism, or maldescensus testis, occurs when one or both testicles fail to descend into the scrotum by six months of age, remaining in the abdominal, inguinal, or ectopic locations. Ectopic testes may be found suprafascially, perineally, or crurally [9,10]. In dogs, testicular descent is typically completed 35–40 days post-birth, while in cats, it occurs at birth. Delayed descent refers to testes reaching the scrotum later than expected. Canine cryptorchidism is multifactorial, involving breed-specific genetic (mono/polygenic), epigenetic, and environmental factors [11]. In cats, heredity remains unclear, though it is more common in Persians, Ragdolls, and European Shorthairs [12].

Cryptorchidism affects different animal species, with unilateral cases more prevalent than bilateral ones. Unilateral cryptorchidism occurs at rates of 78%, 90%, 45-70%, 81-93%, 66-89%, 59%, 100%, and 62% in tomcats, cattle, dogs, horses, humans, pigs, rabbits, and sheep. Typically, the right testicle is more often retained and only approximately 1% of cases including both testicles in the abdomen [3]. One potential cause in dogs is an inherited autosomal recessive trait, which is more common in small dog breeds than large ones [13]. Research suggests that close inbreeding (Sibling mating) in dogs over multiple generations enhance the risk of cryptorchidism [14]. Although, retained testes cannot produce sperm, but they can still exude testosterone, leading to undesired territorial behavior, aggressiveness, and foul-smelling urine [15].

Bilateral abdominal cryptorchidism can lead to sterility in cats and dogs [16]. This might be due to factors such as germ cell disarray and sloughing into the lumen, severe hypo-spermatogenesis, the lack of Sertoli cells, hyperplasia of Leydig cells, and interstitial hemorrhages [17]. Cryptorchidism is associated with persistent Mullerian duct syndrome (PMDS), feminization syndrome, prostatic cysts, and seminoma [3, 18-21], a 17-year-old Miniature mixed breed dog, feminization syndrome, prostatic cysts, and seminoma [3,19-21]. In a study on unilateral cryptorchidism, the affected testis showed no spermatogenesis, and after 52 weeks, germ cell numbers decreased significantly in the contralateral testis. The cryptorchid testis produces high levels of estradiol-17-beta, which inhibits endocrine and spermatogenic processes in the other testis in dogs [14]. Congenital abnormalities in cryptorchid dogs include patella luxation, hip dysplasia, penile and preputial issues, inguinal and umbilical hernias [22]. Eutopic testis, gland atrophy, and hyposexualism (reduced size of the prepuce and penis) have all been observed as anomalies [23]. Animals with bilateral cryptorchid are prone to obesity, abrupt aggression, anxiety, and lethargy. Testicular torsion is more likely to occur in abdominal cryptorchidism because they are more mobile than those in the scrotum [24]. Abdominal cryptorchid testicular torsion in dogs are more often related to testicular neoplasia, notably Sertoli cell tumors or seminomas, with a reported 36% frequency of torsion in neoplastic testes [1]. Sertoli cell tumors are more common in abdomen-retained testes, while inguinal testes typically form seminomas [1]. Also, retained testes are prone to neoplastic transformation with higher risk (9.2-13.6 times higher) than canine scrotal testes [25]. Spermatocytic seminoma accounts for 32-48% of testis cancers in dogs (some may be gonocytic seminomas), followed by 27-42% of Leydig cell tumors and 20-40% of Sertoli cell tumors. Gonocytic seminomas tend to be more invasive than spermatocytic seminomas [26].

Sertolioma typically affects the undescended testes and occurs bilaterally in 10% of cases. The tumor normally grows slowly and spreads to the sublumbar lymph node, liver, kidney, spleen, pancreas, lung, and heart, accounting for about 10% of all metastases [27]. A thorough abdominal examination is recommended to assess metastases, focusing on lymph nodes, kidneys, spleen, pancreas, and liver. Canine-retained testes that have not developed neoplastic transformation are small, oval, echo-poor, and structurally normal [28]. The size of the cryptorchid testicles is affected due to location, indicating substantial clinical alterations such as atrophy and/or congestion of the testicles. Cryptorchidism-related postpubertal problems, including testis tumors, atypical reproductive hormone concentrations, and altered spermatogenesis in the scrotal testis, are not produced by elevated abdominal temperature but rather as a delayed manifestation of testis dysgenesis [29]. Higher temperatures can negatively affect testicular cell types and cause neoplastic development in non-descending testicles due to inherent defects [30].

Palpation was only 48.0% effective in locating retained testis [31]. The absence of one or both testes in the scrotum is a definitive diagnostic indicator. A testicle is often located between the scrotum and the inguinal canal, within subcutaneous tissue, or may not be palpable at all [32]. Invasive procedures, including exploratory laparotomy and laparoscopy for locating a testicle, can result in significant complications [7]. Abdominal radiographs cannot reveal cryptorchidism or testicular torsion. However, use of radiography may be inclusive for a soft-tissue opaque mass caudal to the kidney or cranial to the urinary bladder [33]. Ultrasound is more sensitive than surgery for locating undescended testes (96.6% and 100% for abdominal and inguinal retained testes, respectively [34].  Retained testes in horses were distinguished from other abdominal organs by identifying specific testicular features, including the hyperechoic albuginea and central vein or epididymis [35]. Normal testes have coarse and homogenous echotexture, a central hyperechoic mediastinum testis, a well-defined testicular capsule, and hyperechoic connective tissue flecks [36]. But, neoplastic testes do not have discernible mediastinum testes may not be effective in identifying neoplastic testes, as they may not have a discernible mediastinum testis. Canine neoplastic testes can range from well-defined small nodules to large multifaceted masses that disrupt normal testicular anatomy [28]. A CT scan should be considered for any inconclusive or unclear findings on an ultrasound [37].

The treatments for cryptorchidism as discussed in above sections, include hormonal therapy (Table 2) and manual traction [2,38,39]. GnRH may cause testicular enlargement and migration [32]. Androgen supplementation is not suggested due to its potential to gonadotrophin liberation and premature closure of growth cartilage in young animals [40]. Hormonal treatment affects normal fall of testis to the scrotum, resulting in a late descent. Furthermore, some authors advise against hormonal therapy due to the potential for genetic transmission [41,42]. Hormonal therapy for descending inguinal, inguinal-scrotal, or abdominal cryptorchid testicles should be used with caution and only when necessary. This allows for a posterior orchiectomy, avoiding more sophisticated surgeries like laparotomy, which can be risky for animals [32]. Surgical therapy should be performed on dogs only after six months age to avoid the possibility of late descent [1]. The inguinal method involves tracing the vaginal process and inguinal extension of the gubernaculum to locate and remove the retained testis [43]. Laparoscopic surgery has become more common in small animals due to its minimal invasiveness and improved view of organs. Cryptorchidectomy in dogs can be performed using single or multiport laparoscopic techniques [7]. Vasectomy is reserved for young animals and can be accomplished through inguinal or abdominal routes, depending on the position of the ectopic testicle [42], and is related to sperm granuloma [44]. Complete castration can prevent prostatic and skin problems, anal dysplasia, and carcinomas by removing the source of the sex steroid hormone, unlike vasectomy [32]. Surgical consequences may include infection, bleeding, ecchymosis surrounding incisions, edema, and subcutaneous emphysema [5]. Feminization syndrome caused by Sertoli cell tumors is typically reversible with complete tumor excision and no metastatic illness [45]. Hormonal treatment attempts to treat cryptorchidism in dogs have not been successful, and orchiopexy is considered unethical because of the hereditary nature of the disease [7]. Additionally, the orchidopexy treatment may reduce blood supply to tissues by stretching arteries. Castration is, therefore the standard course of treatment for cryptorchidism [6].

Table 2. Treatment protocol for cryptorchidism in dogs

CONCLUSION

This study highlights abdominal cryptorchidism as a reproductive abnormality in dogs, which require timely diagnosis and surgical intervention. Ultrasonography is considered to be more effective than radiographic imaging in detection of cryptorchidism. Early diagnosis prevents complexities like testicular torsion, testicular neoplasia, infertility and hormonal imbalances. Hence, routine clinical examinations, genetic screening and adaptation of healthy breeding practices are critical in reducing prevalence of cryptorchidism in canine population.

ACKNOWLEDGEMENTS

None.

CONFLICTS OF INTEREST

The authors declare no conflict of interest.

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