Spinal epidermoid cyst in a SJL mouse: case report and literature review.

This research presents the first recorded case of a spinal epideroid cyst, which is a type of benign growth, in a specific strain of mouse (SJL). The paper also provides a brief review of the occurrence of such cysts in different animals.

Spinal Epidermoid Cyst in SJL Mouse

• This research identifies an unusual case of a spinal epidermoid cyst (EC) in a SJL mouse. Prior to this, there are no known records of such a condition in this strain of mice.
• The EC was not initially obvious; it did not show any distinct symptoms nor did it affect the mouse’s performance on a rotating rod test—an assessment often used to evaluate motor coordination and balance in rodents.
• Upon microscopic inspection, researchers found an oval-shaped cyst. It was lined by stratified squamous epithelium, a type of tissue, and was attached to the meninges, layers of tissue that protect the brain and spinal cord. This cyst was causing moderate compression of the surrounding lumbar spinal cord, located in the lower back.

Occurrence of ECs in Animals

• The paper offers a broad review of the prevalence of ECs in a range of animals, including dogs, horses, mice, and rats.
• For mice and rats, researchers note that these growths are typically situated in the caudal region of the spinal cord, near the bottom of the spine. The occurrence of these cysts is variable and appears to be dependent on the strain of the animals.
• Interestingly, researchers found that ECs in mice and rats generally do not present apparent clinical signs. In other words, these cysts seem to cause no evident health issues in the animals, and thus, can be considered as incidental findings—unintentionally detected anomalies that may not have direct significance to the primary disease or condition being studied.