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Case Reports
. 2023 Sep 15:13:1156566.
doi: 10.3389/fonc.2023.1156566. eCollection 2023.

Primary mediastinal seminoma presenting with paraneoplastic anti-Hu encephalitis: a case report and literature review

Chelsey M Williams  1 , Derek B Allison  2   3 , Adam B Coleman  4 , Roshmita Bardhan  5 , Jordan D Miller  6 , Zin W Myint  2   7
Affiliations
Case Reports

Primary mediastinal seminoma presenting with paraneoplastic anti-Hu encephalitis: a case report and literature review

Chelsey M Williams et al. Front Oncol. .

Abstract

Primary mediastinal seminomas are exceedingly rare tumors, often localized to the anterior mediastinum. They may present with numerous complications, including superior vena cava syndrome, chylothorax, and pericardial effusions. Less commonly, they may present with paraneoplastic encephalitis. In this report we describe a case of a 19-year-old male with no significant past medical history who presented with bilateral hearing loss, progressive neuropathy, and ataxia. Subsequently the patient was found to have mediastinal mass with a high-titer anti-Hu antibody. To our knowledge, only one other case of mediastinal seminoma presenting with anti-Hu antibodies has been described in the literature. In this report, we describe a rare case of mediastinal seminoma, describe treatment options, and discuss additional known cases presenting with paraneoplastic encephalitis.

Keywords: ANNA-1; anti-Hu; bilateral hearing loss; paraneoplastic encephalitis; primary mediastinal seminoma; rhombencephalitis.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
(A) Nodular area with central low density in the left side of the thymus, measuring roughly 32 mm long axis indicative of mediastinal seminoma (yellow indicator). (B) Computed tomography of axial chest demonstrates anterior mediastinal mass (red arrow).
Figure 2
Figure 2
(A) Section of thymus shows cystic degeneration at the right side of the image (white space) and a rim of thymus showing intact, normal Hassel's corpuscles and a diffusely infiltrative malignant process. Tumor cells are present as single, dispersed cells, as well as cords and clusters, in a background of lymphocytes and thymic epithelial cells. Although there is cystic degeneration, the diffusely infiltrative growth pattern results in more of thickening of the thymic epithelium rather than a discrete mass. H&E stain, 20x magnification. (B) Higher magnification showing tumor infiltrative as single cells, cords, and clusters between lymphocytes, thymic epithelium, and Hassel's corpuscles. The tumor cells are large, contain clear to eosinophilic cytoplasm, and have large, round nuclei with prominent nucleoli. H&E stain, 40x magnification. (C) Pancytokeratin stain shows diffuse staining in the normal thymic epithelium in the lower left portion of the image. In contast, clusters of tumor cells show focal, punctuate staining. AE1/AE3 stain, 40x magnification. (D) Clusters and isolated seminoma cells show nuclear posibility with the germ cell marker OCT3/4. OCT3/4 stain, 40x magnification. (E) Clusters and isolated seminoma cells show nuclear positivity with the germ cell marker SALL4. SALL4 stain, 40x magnification. (F) Background thymic epithelium stain positively with p63 while the seminoma cells that are present in clusters are negative. p63 stain, 40x magnification. H&E, Hematoxylin and eosin; AE1/AE3, cytokeratin stain; OCT 3/4, octamer-binding transcription factor 4; SALL4, spalt like transcription factor 4.
Figure 3
Figure 3
A detailed diagnosis and treatment timeline of mediastinal seminoma with paraneoplastic anti-Hu encephalitis.
See this image and copyright information in PMC

References

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