Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Case Reports
. 2021 Mar;33(2):336-339.
doi: 10.1177/1040638721990896. Epub 2021 Feb 1.

Thymoma in an aged backyard Leghorn chicken, with reviews of a database and literature

Julia Blakey  1 , Carmen Jerry  1 , Ana da Silva  1 , Simone Stoute  1
Affiliations
Case Reports

Thymoma in an aged backyard Leghorn chicken, with reviews of a database and literature

Julia Blakey et al. J Vet Diagn Invest. 2021 Mar.

Abstract

A 7-y-old backyard Leghorn chicken (Gallus domesticus) was submitted to the California Animal Health and Food Safety Laboratory System (CAHFS)-Turlock branch for postmortem examination, with a history of unexpected death. At postmortem examination, a hemorrhagic soft tissue mass was observed in the cervical region. Microscopically, a densely cellular neoplasm of polygonal epithelial cells and small lymphocytes was observed. The microscopic features of the neoplasm in combination with positive immunohistochemistry for pancytokeratin and CD3 were used to classify the lesion as a thymoma. Thymoma was diagnosed in only 5 birds submitted to CAHFS from 1990 to 2019. Thymoma has been described only rarely in birds, and is an unusual diagnosis in backyard chickens.

Keywords: California; backyard chickens; thymoma.

PubMed Disclaimer

Conflict of interest statement

Declaration of conflicting interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Figures

Figure 1,2.
Figure 1,2.
Thymoma in a 7-y-old backyard Leghorn chicken. Figure 1. A soft tissue mass enveloped in clotted blood (asterisk) is present in the subcutis of the neck, cranial and left of the celomic inlet. Figure 2. The soft tissue mass was surrounded by clotted blood and adipose tissue, and contained 2 cavities that were distended with clotted blood (asterisks).
Figures 3-8.
Figures 3-8.
Microscopic examination of a thymoma in a 7-y-old Leghorn chicken. Figure 3. Within the mass are regions comprised of polygonal epithelial cells with abundant finely granular eosinophilic cytoplasm and round nuclei with open chromatin and a prominent nucleolus. H&E. Figure 4. Concentric, lamellated bodies with deeply eosinophilic cytoplasm, reminiscent of Hassall corpuscles, are present. H&E. Figure 5. Abundant small lymphocytes populate the mass. Inset: high magnification of small lymphocyte population. H&E. Figure 6. The mass is partially encapsulated. Regions of necrosis (N) and pseudocyst formation (C). H&E. Figure 7. Strong cytoplasmic immunoreactivity to pancytokeratin in the epithelial cells. Figure 8. Small lymphocytes have strong cytoplasmic and membranous immunoreactivity to CD3.
See this image and copyright information in PMC

References

    1. Aronsohn M. Canine thymoma. Vet Clin North Am Small Anim Pract 1985;15:755–767. - PubMed
    1. Balaguer L, et al.. A poorly-differentiated squamous cell thymoma in a chicken with lymphoma. Avian Pathol 1995;24:737–741. - PubMed
    1. Ciriaco E, et al.. Age-related changes in the avian primary lymphoid organs (thymus and bursa of Fabricius). Microsc Res Tech 2003;62:482–487. - PubMed
    1. Feldman WH. Thymoma in a chicken (Gallus domesticus). Am J Cancer 1936;26:576–580.
    1. Kendall MD. Avian thymus glands: a review. Dev Comp Immunol 1980;4:191–209. - PubMed

Publication types