Renal mucus gland cystadenomas in a horse.

The study discusses a case where a 35-year-old horse was diagnosed with renal mucus-gland cystadenomas, a rare tumor, during its autopsy at the University of Kentucky Livestock Disease Diagnostic Center. This diagnosis is noteworthy for veterinarians as this type of tumor should be considered when cystic structures are identified in a horse’s kidney.

Objective and Methodology

• The main objective of the research was to provide crucial pathological insights into observing and diagnosing uncommon tumors in horses such as renal mucus gland cystadenomas.
• During the examination, the horse was dead and submitted for necropsy at a disease diagnostic center.

Findings and Outcomes

• The researchers found multiple cystic structures in the right renal medulla and cortex of the horse’s kidney, which were not expected.
• The sizes of these cysts ranged from 1 to 4 cm in diameter. Microscopic analysis revealed that these formations pressed against the normal architecture of the kidney.
• These cysts were lined with a tall columnar epithelium, a kind of lining or barrier that separates the body’s internal structures, occasionally forming papillary projections. Papillary projections can usually indicate a benign or malignant growth.
• Inside these cysts, large amounts of mucicarmine and periodic acid-Schiff (PAS)-positive mucinous material were found. These substances are markers often associated with mucus production and epithelial tumors.
• Based on these observations, the team diagnosed the formations as renal mucus gland cystadenomas, a type of tumor largely comprised of mucus-producing cells.

Significance and Conclusion

• The results of this study contribute to the understanding of unusual tumors in horses, specifically renal mucus gland cystadenomas.
• This research informs veterinarians of the need to consider this type of tumor when identifying cystic structures in the kidney of a horse during an autopsy.
• In conclusion, the findings of this autopsy propose an important differential diagnosis in equine pathology.