A Rare Case of Metaplastic Thymoma Presenting With Myasthenia Gravis

Authors

Ilianne Vega Prado, Department of Pathology, The George Washington University, Washington, DC, USA.
John Shymansky, Department of Neurology & Rehabilitation Medicine, The George Washington University, Washington, DC, USA.
Anisha Apte, Department of Surgery, The George Washington University, Washington, DC, USA.
Keith Mortman, Department of Surgery, The George Washington University, Washington, DC, USA.
Henry J. Kaminski, Department of Neurology & Rehabilitation Medicine, The George Washington University, Washington, DC, USA.
Stephanie Barak, Department of Pathology, The George Washington University, Washington, DC, USA.

Document Type

Journal Article

Publication Date

2-1-2024

Journal

International journal of surgical pathology

Volume

32

Issue

1

DOI

10.1177/10668969231168344

Keywords

AE1/AE3; keratin; metaplastic thymoma; myasthenia gravis; terminal deoxynucleotidyl transferase

Abstract

Thymomas are tumors of the mediastinum often associated with autoimmune conditions, in particular myasthenia gravis. In contrast, among the fewer than 40 reports of metaplastic thymoma, myasthenia gravis is rarely found. We describe the fourth patient, and first man, with metaplastic thymoma and myasthenia gravis. A 34-year-old had acute onset of double vision with associated dysphagia and was found to have an elevation of serum acetylcholine receptor antibodies. He underwent a transsternal thymectomy. Tissue sections showed a biphasic proliferation of keratin-positive epithelial cells with a complement of spindle cells confirming the diagnosis of metaplastic thymoma. Terminal deoxynucleotidyl transferase (TDT)-positive T lymphocytes were rare and only found in the periphery of the tumor, consistent with thymic remnant. A gene fusion, with an in-frame fusion between genes Exon5 (NM_001130145) and Exon2 (NM_032427) was found, supporting further the diagnosis of metaplastic thymoma (Anchored multiplex RNA sequencing [Archer Dx, Boulder, CO] assay). The patient's gender and relatively young age, the presence of an autoimmune condition, and the lack of lymphocytic infiltrate all contribute unusual features to this case and suggest avenues for further exploration.

APA Citation

Vega Prado, Ilianne; Shymansky, John; Apte, Anisha; Mortman, Keith; Kaminski, Henry J.; and Barak, Stephanie, "A Rare Case of Metaplastic Thymoma Presenting With Myasthenia Gravis" (2024). GW Authored Works. Paper 4450.
https://hsrc.himmelfarb.gwu.edu/gwhpubs/4450

Department

Neurology