Liviu Cătălin Burtan, Ivona Popovici, Alexandra Ciubotariu
ABSTRACT. Ovarian cystic disease is a common condition in guinea pigs (Cavia porcellus). Surgical intervention is considered the definitive treatment, effectively preventing disease recurrence, progression, and complications. A 5-year-old female guinea pig was referred to our clinic with nonspecific signs of lethargy and gastrointestinal disturbances that had emerged over the previous week. Diagnostic imaging identified a large abdominal mass, consistent with a cyst, extending throughout the right hemiabdomen, warranting immediate surgical intervention. Safe removal of the cyst via an ovariectomy procedure was performed with particular attention to the species-specific anatomical and physiological challenges. Managing the adhesions that had formed with the intestinal mass proved to be a complex step, requiring precise dissection to ensure secure and complete removal. Histopathological analysis of the mass revealed a ciliated cuboidal to columnar epithelium lining the cyst cavity, originating from the rete ovarii, indicative of a serous cystadenoma. This study highlights the importance of early detection and emphasises the role of elective spaying in preventing severe complications. It also provides valuable surgical insights for veterinary practitioners by documenting the largest ovarian cyst reported in a guinea pig. The case presents a detailed approach to managing species-specific challenges, with the aim of improving clinical outcomes for these patients.
Keywords: Cavia porcellus; histopathology; large ovarian cystadenoma; surgery.
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ALSE and ACS Style
Burtan, L.C.; Popovici, I.; Ciubotariu, A. Massive ovarian cyst in a guinea pig: surgical insights. Journal of Applied Life Sciences and Environment 2025, 58 (1), 43-52.
https://doi.org/10.46909/alse-581164
AMA Style
Burtan LC, Popovici I, Ciubotariu A. Massive ovarian cyst in a guinea pig: surgical insights. Journal of Applied Life Sciences and Environment. 2025; 58 (1): 43-52.
https://doi.org/10.46909/alse-581164
Chicago/Turabian Style
Burtan, Liviu Cătălin, Ivona Popovici, and Alexandra Ciubotariu. 2025. “Massive ovarian cyst in a guinea pig: surgical insights.” Journal of Applied Life Sciences and Environment 58, no. 1: 43-52.
https://doi.org/10.46909/alse-581164
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Massive ovarian cyst in a guinea pig: surgical insights
Liviu Cătălin BURTAN1, Ivona POPOVICI2 and Alexandra CIUBOTARIU1,*
1Clinics Department, Faculty of Veterinary Medicine, “Ion Ionescu de la Brad” Iasi University of Life Sciences, 8, Mihail Sadoveanu Alley, 700489, Iasi, Romania; email: burtan_liviu@yahoo.com
2Preclinics Department, Faculty of Veterinary Medicine, “Ion Ionescu de la Brad” Iasi University of Life Sciences, 8, Mihail Sadoveanu Alley, 700489, Iasi, Romania; email: ivona.laiu@yahoo.com
*Correspondence: alexandra.neamtu21@gmail.com
Received: Dec. 09, 2024. Revised: Feb. 10, 2025. Accepted: Feb. 12, 2025. Published online: Feb. 26, 2025
ABSTRACT. Ovarian cystic disease is a common condition in guinea pigs (Cavia porcellus). Surgical intervention is considered the definitive treatment, effectively preventing disease recurrence, progression, and complications. A 5-year-old female guinea pig was referred to our clinic with nonspecific signs of lethargy and gastrointestinal disturbances that had emerged over the previous week. Diagnostic imaging identified a large abdominal mass, consistent with a cyst, extending throughout the right hemiabdomen, warranting immediate surgical intervention. Safe removal of the cyst via an ovariectomy procedure was performed with particular attention to the species-specific anatomical and physiological challenges. Managing the adhesions that had formed with the intestinal mass proved to be a complex step, requiring precise dissection to ensure secure and complete removal. Histopathological analysis of the mass revealed a ciliated cuboidal to columnar epithelium lining the cyst cavity, originating from the rete ovarii, indicative of a serous cystadenoma. This study highlights the importance of early detection and emphasises the role of elective spaying in preventing severe complications. It also provides valuable surgical insights for veterinary practitioners by documenting the largest ovarian cyst reported in a guinea pig. The case presents a detailed approach to managing species-specific challenges, with the aim of improving clinical outcomes for these patients.
Keywords: Cavia porcellus; histopathology; large ovarian cystadenoma; surgery.
INTRODUCTION
Over the past few years, guinea pigs have continued to grow in popularity as pets, valued for their friendly nature and ease of care (Shahbandeh, 2024). Ovarian cysts are a commonly observed medical condition in guinea pigs, developing throughout the female’s reproductive cycle and often associated with hormonal imbalances, reproductive complications, and an increasing prevalence with age (Rachel, 2019). Clinical symptoms usually include nonspecific signs such as lethargy, reduced appetite, abdominal distension, behavioural changes, or, in some cases, bilateral alopecia. Diagnosis relies on clinical signs, palpation, and imaging techniques such as ultrasonography or computed tomography (Bertram et al., 2018). Because of the high risk of potentially serious uterine disorders, permanent treatment requires either ovariectomy or ovariohysterectomy (Sadar and Gleeson, 2025). The surgical procedure demands specialised knowledge to prevent complications. Thus, a documented resource with detailed surgical insights into cyst removal is essential, especially because similar data remain limited in the veterinary literature. This report details the largest ovarian cyst described to date, highlighting the organism’s adaptability and contributing to advancements in veterinary knowledge and clinical practice.
CASE PRESENTATION
A 5-year-old intact female guinea pig weighing 0.9 kg was referred to the Faculty of Veterinary Medicine Iași for evaluation. The owner reported a 7-day history of gastrointestinal disturbances, including alternating episodes of diarrhoea and constipation, anorexia, and accidental ingestion of plastic material. The patient’s regular diet primarily consisted of hay, lettuce, carrots, and a variety of other vegetables.
On clinical examination, abdominal palpation revealed a large, immobile mass on the left side of the abdomen. The patient was alert, with pink, well-hydrated mucous membranes and physiological parameters within normal limits. No other significant clinical findings were noted.
Radiographic imaging of the abdomen revealed a well-defined, circular mass in the right hemiabdomen, displacing the intra-abdominal organs toward the left side of the abdominal cavity and exerting a significant mass effect (Figure 1).
Figure 1 – Dorsoventral radiograph of a 5-year-old guinea pig showing a large mass in the right hemiabdomen
Abdominal ultrasonography identified a mass consistent with a cyst. Considering the overall clinical and diagnostic findings, exploratory laparotomy and surgical excision of the mass were deemed necessary.
General anaesthesia was achieved with ketamine (40 mg/kg intramuscularly) plus xylazine (5 mg/kg intramuscularly). Following induction, a face mask was used for oxygen and anaesthetic agent delivery (isoflurane 1.5%). Prior to the procedure, the oral cavity was thoroughly examined to remove any food residues or excessive salivation, ensuring an unobstructed airway and reducing the risk of aspiration during anaesthesia.
An air-warming device was used to prevent hypothermia during the procedure. The patient was placed in dorsal recumbency, and the surgical area was prepared. A ventral midline incision was performed, and the abdominal cavity was accessed through a small incision in the elevated musculature, carefully extended along a grooved probe to protect the organs (Figure 2a). Surgical exploration revealed a cyst occupying the entire right side of the abdomen. The cyst was gently exteriorised from the abdominal cavity, revealing its connection to the reproductive system and confirming it as an ovarian cyst (Figure 2b and Figure 2c). Additionally, multiple adhesions to the intestinal loops were identified. These adhesions were carefully lysed using a combination of scissor and gauze-assisted blunt dissection (Figure 3 and Figure 4).
Once the ovarian cyst had been completely isolated, haemostatic forceps were placed, and the ovarian pedicle was ligated using a 3-0 absorbable suture.
Figure 2 – Ventral midline laparotomy and cyst assessment. a. The incision was extended using a cannulated probe to protect the intra-cavitary organs. b. The cyst was exteriorised, revealing its multilocular structure with a smooth, translucent surface. The left side of the cyst was adhered to the intestinal loops, which were firmly connected to its surface. c. The right side of the cyst was attached to the ovary. The arrow indicates the intact uterine horn for reference
Figure 3 – Cyst dissection. The adhesions were carefully separated using fine scissors to preserve the integrity of the cystic walls
Figure 4 – Cyst dilaceration. Gentle dilaceration with gauze was performed in areas of less dense adhesions to separate the cyst while minimising trauma
An additional transfixing ligature was placed on the uterine horn, and the ovary was excised along with the cyst (Figure 5). A routine abdominal exploration was performed prior to laparorrhaphy, and no additional abnormalities were detected except for an enlarged uterus (Figure 6).
Particular attention was given at this stage to prevent complications caused by improper or excessive handling of the internal organs. Ovariohysterectomy was necessary because of the significant uterine enlargement. After completing the well-established procedure following standard surgical steps, the abdominal wall was closed.
Following laparorrhaphy (Figure 7), the subcutaneous connective tissue was sutured, with additional cruciate sutures placed to enhance tensile strength.
Anaesthesia and recovery proceeded with no signs of adverse reactions or complications. Postoperative care included analgesia (buprenorphine 0.05 mg/kg subcutaneously), antibiotic therapy (enrofloxacin 5 mg/kg subcutaneously), fluid therapy, and proper hygiene maintenance.
Figure 5 – Cyst removal
Figure 6 – Routine abdominal exploration before closing the abdomen. Final inspection of the abdominal cavity ensured that all structures were intact, with the remaining viscera showing no abnormalities except for the enlarged uterus
Figure 7 – Laparorrhaphy
For histopathological analysis, the cyst samples were fixed for 24 hours using Bouin’s solution, dehydrated in successive ethanol baths, clarified in butanol, and embedded in paraffin. Sections of 5 µm were stained with haematoxylin and eosin, then examined and photographed using a Leica DM500 microscope with an ICC50 W camera and LAS V4.13 software.
Histological examination revealed that the cysts were lined with an epithelium composed of cells of varying height, ranging from low cuboidal to columnar (Figure 8a, b). Both ciliated and non-ciliated cells were present in the lining epithelium.
The cilia were observed at the apical pole of the cells, either individually or in groups.
In cells with multiple cilia, the basal bodies were clearly visible and arranged in a row (Figure 9a). Some cells exhibited a more basophilic cytoplasm, while others had a less basophilic appearance (Figure 9b).
The epithelial cells lining the cysts displayed irregularly shaped nuclei, located centrally in cuboidal cells or displaced toward the basal pole.
Figure 8 – a. A septum separated two cysts, with a core of dense collagenous connective tissue and ciliated epithelium on both sides. Haematoxylin and eosin, ×100. b. The epithelium lining the cysts consisted of cuboidal cells (arrowheads) and columnar cells (arrow), with nuclei positioned either centrally or at the basal pole of the columnar cells. Nuclear atypia was observable. Haematoxylin and eosin, ×400
Figure 9 – a. The basal bodies of the cilia were aligned in a row (short arrow). b. The epithelial lining of the cysts consisted of cells with a more basophilic cytoplasm (black arrow) and cells with a less basophilic cytoplasm (red arrow). Haematoxylin and eosin, ×400
DISCUSSION
In a study involving 1,000 pet guinea pigs, ovarian cystic disease was identified as the third most prevalent disorder in this species, following dental diseases and skin problems (Minarikova et al., 2015). However, the discovery of an unusually large ovarian cyst, exceeding previously reported sizes in the literature, underscores the importance of documenting such cases. Studying these extreme cases allows specialists to improve their understanding of the condition, its potential effects, and appropriate management strategies.
In human medicine, giant ovarian cysts are classified as those exceeding 10 cm in diameter (Yeika et al., 2017). In our case report, the cyst measured 9.5 cm – slightly below the human classification threshold but extraordinary considering the significantly smaller overall size of the patient.
Food was withheld for only 2 hours because of the increased risk of hypoglycaemia in small rodents. According to multiple authors, fasting in this species can lead to postoperative gastrointestinal disturbances (Flecknell, 2023; Lamont et al., 2024).
The decision to proceed with a ventral midline incision in this guinea pig was necessary and appropriate, despite the established benefits of dorso-lateral ovariectomy such as smaller incisions, reduced gastrointestinal manipulation, and shorter operative time (Rachel, 2019). The primary reasons for this choice were the presence of significant adhesions and the unusually large size of the mass, which rendered fine-needle aspiration or a minimally invasive approach impractical and unsafe. This approach allowed better visualisation, precise dissection of the adhesions, and safe removal of the mass while minimising the risks associated with incomplete excision or complications. The incision was sized to allow for the safe removal of the cyst while minimising tissue trauma, considering the thick and less elastic nature of guinea pig skin. Moreover, this species is known to exhibit a more pronounced inflammatory response to visceral manipulation, making careful handling essential (Miwa and Sladky, 2016).
Although ovarian cysts are commonly observed in guinea pigs, their size typically ranges from 0.5 to 7.0 cm (Greenacre, 2015; Nielsen et al., 2003; Preetha et al., 2011; Sadar and Gleeson, 2025).
Table 1 summarises comparative findings from various authors regarding these dimensions. The frequency and size of ovarian cysts in guinea pigs progressively increase with age (Nielsen et al., 2003). To our knowledge, this represents the first reported case of a cyst measuring up to 9.5 cm in diameter in a guinea pig, exceeding the maximum size documented in the existing literature. This finding highlights the largest cyst reported to date.
Table 1
Size ranges of ovarian cysts reported in studies to date
| Cyst size (cm) | Reference |
| 0.2–8.0 | Bertram et al., 2018 |
| 0.5–7.0 | Keller et al., 1987 |
| 6.0 | Minarikova et al., 2015 |
| 5.0 | Jenkins, 2010 |
| 0.4–4.4 | Nielsen et al., 2003 |
| 0.9–3.8 | Kohutova et al., 2018 |
| 3.0 | Greenacre, 2015 |
| 0.1–2.5 | Quattropani, 1977 |
| 1.5 | Preetha et al., 2011 |
This case aligns with findings in the literature indicating that ovarian cystic disease often remains asymptomatic until the condition progresses to a critical stage (Minarikova et al., 2015). However, what distinguishes this case is the organism’s ability to tolerate an exceptionally large cyst occupying up to half of the abdominal cavity. Surprisingly, clinical symptoms only appeared in the last week, highlighting the ability to sustain homeostasis over an extended period despite the cyst’s size. Unlike other reports, progressive hair loss in the flank region was not observed in this case (Pilny, 2014). However, several studies have reported findings similar to ours, suggesting that alopecia is less common (Nielsen et al., 2003; Preetha et al., 2011).
The formation we examined exhibited characteristics consistent with serous cystadenoma, as described in previous studies (Quattropani, 1978). In guinea pigs, serous ovarian cysts most frequently develop from the rete ovarii (Shi et al., 2002), although other factors, such as infections, neoplasia, or persistent tertiary follicles that fail to undergo luteinisation, may also contribute to their formation (Bean, 2013). The formation of the cyst cavity and the accumulation of fluid can be explained by the intercellular junctions present between the epithelial cells lining the cyst cavity. Adhesion junctions, such as spot-like desmosomes (also called maculae adherentes) or belt-like zonulae adherentes, are present; however, studies on the ultrastructure of rete cyst epithelium in guinea pigs indicate that there are few or no tight occluding junctions between the cells (Kierszenbaum and Tres, 2011). The low presence or even absence of tight junctions explains the permeability of this epithelium. Tight junctions in junctional complexes function as occluding junctions that prevent molecules from passing through the space between cells, forcing them to enter the cell in order to move between body compartments (Bhat et al., 2019). The accumulation of cyst fluid, attributed to the lack of tight junctions involved in maintaining the paracellular pathway barrier, is further supported by the absence of secretory granules in the epithelial cells of the cysts, as revealed by light and electron microscopy studies (Bean, 2013).
CONCLUSIONS
To our knowledge, this case represents the largest ovarian cyst (cystadenoma) reported in guinea pigs to date, highlighting the organism’s remarkable adaptability in managing significant topographic changes. This makes it a key case for advancing veterinary knowledge and improving clinical practices.
Future studies should investigate the hormonal and genetic mechanisms driving the formation of massive cysts that resist rupture despite their size and the pressure exerted during palpation. Additionally, the remarkable resilience and adaptive capacity of the organism should also be examined.
Author contributions: Conceptualization: AC; Methodology: AC; Analysis: LB; Histological analysis: IP; Investigation: IP; Resources: LB; Data curation: AC; Writing: AC; Review: LB; Supervision: LB. All authors declare that they have read and approved the publication of the manuscript in this present form All authors declare that they have read and approved the publication of the manuscript in this present form.
Funding: There was no external funding for this study.
Conflicts of interest: The authors declare no conflict of interest.
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Burtan Liviu Cătălin, Ciubotariu Alexandra, Popovici Ivona
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