Mediastinum
Nonneoplastic
Thymic dysplasia
Author: Hanni Gulwani, M.B.B.S.
Topic Completed: 1 December 2012
Minor changes: 20 November 2019
Copyright: 2003-2019, PathologyOutlines.com, Inc.
PubMed Search: Thymic dysplasia
Table of Contents
Definition / general | Clinical features | Gross description | Microscopic (histologic) description | Differential diagnosisCite this page: Gulwani H. Thymic dysplasia. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/mediastinumthymicdysplasia.html. Accessed January 16th, 2021.
Definition / general
- Congenital thymic alteration due to developmental arrest
- Lack of differentiation of thymic epithelium, responsible for absence of Hassall corpuscles, is main feature (Histopathology 1992;21:499)
Clinical features
- Associated with severe combined immunodeficiency syndrome, ataxia telangiectasia, chromosomal instability syndromes, Nezelof syndrome (Arch Pathol Lab Med 1987;111:1118)
- Incomplete form of DiGeorge syndrome is congenital anomaly with a constellation of findings that includes thymic hypoplasia (J Cutan Pathol 2008;35:380); complete form has absent thymus
Gross description
- Small thymus (< 5 g)
Microscopic (histologic) description
- Tubules and rosettes of primitive appearing epithelium without segregation into cortical and medullary regions
- No Hassall corpuscles, no / rare lymphocytes
Differential diagnosis
