99 - An unusual vagal mediastinal mass of unknown etiology

Poster Board Number: 99
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Co-authors:

Andy Grass, PhD - Associate Professor, Anatomy, A.T. Still University School of Osteopathic Medicine in Arizona

Abstract Body : A rare superior mediastinal mass was discovered upon dissection of a 95-year-old female donor, whose cause of death was listed as a pulmonary embolism. The mass encapsulated the right vagus nerve, and was directly adjacent to the arch of the azygos vein and the right upper lobar pulmonary artery. The exact identification and etiology of the mass was initially unclear, which prompted further investigation.



The mass was oval-shaped and well encapsulated, measuring 40 mm x 24 mm x 20 mm. The anterior surface was rough and irregular in texture, while the posterior surface was smooth. The mass was gritty, light tan in color, and appeared to be either ossified or calcified, with a focal area of elongated dark brown discoloration. Externally, the mass was hard and extremely difficult to cut through during gross examination. Internally, the mass was a lighter tan color, much softer than the external surface, and was friable with caseous features.



Based on these characteristics, we believe that this mass may be one of three pathologies: a vagal schwannoma, a vagal paraganglioma, or a tuberculosis nodule. Based on its location, we initially assumed this mass to be a schwannoma. But upon further examination and dissection, we believe this mass to more likely be a paraganglioma or TB nodule. Patient history of the donor was limited, making a firm diagnosis more challenging.



When histological results are obtained, and a final determination of this mass is made, it will provide an addition to the medical literature of these rare phenomena.