Visualization of radiographic mineral opacities in guinea pigs in the location of the bulbourethral glands may be underdiagnosed

Background: Pathology of male guinea pig accessory sex glands is minimally described. Mineral opacities caudal to the pelvis were identified during evaluation of two index cases presenting with urinary signs. The objective of this study was to identify the prevalence of this radiographic finding, suspected to be bulbourethral glands, and to describe associated clinical signs. Methods: A retrospective review of medical records from a single academic institution was performed identifying male guinea pigs with abdominal radiographs, abdominal computed tomography, and/or necropsy. Available imaging studies were evaluated for mineral opacities caudal to the pelvis and necropsy reports were reviewed. Medical case histories meeting the inclusion criteria were summarized. Results: Six cases met the inclusion criteria, with a prevalence of 5.17% (6/116) amongst male guinea pigs with abdominal imaging that included the soft tissues caudal to the pelvis. Collimation of 25% (28/112) of radiographic studies and 50% (4/8) of computed tomographic studies excluded this region. One necropsy report (3.23%, 1/31) during the study period evaluated the accessory sex glands. The most common clinical signs in identified cases were hematuria (66.7%, 4/6) and stranguria (50%, 3/6). Conclusions and clinical relevance: The clinical significance of radiographic mineralization in the vicinity of the bulbourethral glands is unknown. This radiographic finding may be underreported due to collimation practices which may exclude the soft tissues caudal to the pelvis. Purposeful evaluation of these organs should be performed during imaging and necropsy evaluation to screen and develop better understanding of the clinical significance of this radiographic finding.