# Evolutionary origins of spinal cord tumors: A cross-species systematic review

## TL;DR

This study explores the evolutionary origins of spinal cord tumors by comparing cases in humans and animals, revealing shared patterns that could improve diagnosis and treatment.

## Contribution

The first cross-species synthesis of spontaneous intradural spinal cord tumors in non-human animals.

## Key findings

- Astrocytomas, oligodendrogliomas, and ependymomas were the most common tumor types, with a cervical spinal cord bias.
- Neurological symptoms like limb paralysis and ataxia were similar to those in humans.
- The evolutionary origin of spinal glial vulnerability dates back to the amniote ancestor over 340 million years ago.

## Abstract

Intradural spinal cord tumors, particularly intramedullary glial neoplasms such as astrocytomas, ependymomas, and oligodendrogliomas, are rare in humans but pose significant diagnostic and therapeutic challenges. Despite their clinical importance, little is known about their evolutionary origins or cross-species presentation. This study aimed to synthesize existing veterinary literature on spontaneous intradural spinal tumors in non-human animals to uncover patterns in clinical symptoms, tumor distribution, and histopathological features that may inform human spinal oncology.

We conducted a systematic review of Medline, Embase, and Web of Science using a Preferred Reporting Items for Systematic Reviews and Meta-Analyses-guided approach. Studies were screened using Covidence by multiple independent reviewers. Inclusion criteria required spontaneous, histologically confirmed intradural spinal cord tumors in non-human species. Data extracted included species, tumor type, anatomical location, presenting symptoms, and histopathology. Phylogenetic and life history data were incorporated to explore evolutionary trends.

A total of 109 studies describing 155 cases across 11 animal species were included. Astrocytomas (n = 37), oligodendrogliomas (n = 31), and ependymomas (n = 24) were the most common tumor types, with a notable bias toward the cervical spinal cord. Neurological symptoms were consistent with human intradural tumors: 42% of cases presented with limb paralysis and 28% with ataxia. The most recent common ancestor among affected species was the amniote, suggesting an evolutionary origin of spinal glial vulnerability dating back over 340 million years.

This is the first cross-species synthesis of spontaneous intradural spinal cord tumors in non-human animals. The evolutionary conservation of tumor types and symptom patterns highlights opportunities to develop genetically informed animal models and identify early diagnostic markers. Expanding comparative tumor databases may enhance our understanding of spinal cord oncogenesis and support novel therapeutic strategies in both veterinary and human medicine.