Peer-reviewed veterinary case report
Priapism in a stallion with generalized malignant melanoma.
- Journal:
- Journal of the American Veterinary Medical Association
- Year:
- 1991
- Authors:
- Blanchard, T L et al.
- Affiliation:
- Department of Large Animal Medicine and Surgery · United States
- Species:
- horse
Plain-English summary
A Thoroughbred stallion developed a condition called priapism, which is a persistent erection that occurs without sexual arousal. Despite attempts to treat it with medication and flushing the area with a saline solution, the condition did not improve. After three weeks, the stallion lost the ability to retract his penis and experienced pain, and tests showed that the blood vessels in the penis were blocked. Unfortunately, the stallion was euthanized because the chances of him returning to breeding were very low, and a post-mortem examination revealed he had widespread malignant melanoma, a type of cancer. The treatment did not work, leading to a poor outcome for the stallion.
Abstract
A Thoroughbred stallion developed priapism that was unresponsive to medical treatment and lavage of the corpus cavernosum penis with heparinized 0.9% NaCl solution. Three weeks after onset of priapism, the penis was firm and noncompliant, and penile pain sensation and ability to retract the penis were lost. Ultrasonography confirmed thrombosis of the corpus cavernosum penis. The stallion was euthanatized because of poor prognosis for return to breeding soundness. Necropsy revealed enlargement of numerous lymph nodes. The dorsal penile nerves were demyelinated distal to the crura of the penis. A diagnosis of generalized malignant melanoma was made; however, neither metastasis to the vertebral canal nor compression of spinal nerve roots as they exited the vertebral foramen was found. Priapism is a persistent erection without sexual arousal and is initially unassociated with penile paralysis, but if prolonged, leads to irreversible venous occlusion where collecting veins join the cavernous spaces. Damage to the dorsal penile nerves may explain the long-term penile paralysis and loss of sensation that accompanied priapism in this stallion. Priapism unassociated with the use of phenothiazine-derivative tranquilizers is uncommon in horses.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/2032912/