# Fibrosarcoma Originating from the Pleura in Cotton-Top Tamarin [Oedipomidas (Saguinus) oedipus, Linnaeus 1758]

## TL;DR

A fibrosarcoma originating from the pleura was found in a cotton-top tamarin, a New World primate, with no signs of metastasis.

## Contribution

This case report documents a rare fibrosarcoma in a cotton-top tamarin, expanding knowledge of neoplastic diseases in New World primates.

## Key findings

- A firm pleural mass was identified as a primary fibrosarcoma in a cotton-top tamarin.
- Histological and immunohistochemical analysis confirmed mesenchymal origin of the tumor.
- No metastasis was observed in the abdominal organs or lymph nodes.

## Abstract

Different species of the subfamily Callitrichinae, including tamarins and marmosets, suffer and often succumb to malignant neoplastic diseases, with predominantly enteral symptoms, ranging from colitis or partial obstruction to small bowel diarrhea. The underlying primary neoplasia (carcinoma, adenocarcinoma) often has metastasis to diverse abdominal organs (lymph nodes, liver, pancreas). Other different tumors (adenoma, cystadenoma, fibroma, liposarcoma, fibrosarcoma) are also quite common in these New World primates.

This report describes postmortem findings after the sudden death of a captive-bred middle-aged male cotton-top tamarin (Saguinus oedipus). A firm structure was attached to the pleura in the chest cavity and was assessed as a primary tumor without obvious metastasis. Histologically, the mass showed heterogenicity with immunohistochemistry (IHC) reactivity to vimentin, suggesting a diagnosis of fibrosarcoma of mesenchymal origin.