Presentation
Mild chest pain associated with shortness of breath. No fever, sweating or weight loss.
Patient Data
Lobular non-calcified soft tissue density anterior mediastinal mass lesion.
Heart and lungs are normal.
Large solid-looking anterior mediastinal mass measuring around 9.5 x 4.3 x 6.7 cm with an average attenuation of around 73 HU. No internal necrotic or fatty component or any calcifications are seen. The lesion is closely related to the great vessels of the thorax without any invasion or encasement. A few prominent prevascular lymph nodes measuring 8 mm in short axis. No other radiologically significant lymphadenopathy identified. Generalized decreased parenchymal density of the liver (fatty liver).
- Marked interval improvement of the anterior mediastinal mass.
- Complete interval resolution of previously noted few prominent anterior mediastinal lymph nodes.
Case Discussion
Conclusion: Large soft tissue attenuation anterior mediastinal mass; possible differentials include thymoma and lymphoma.
Procedure: Video-assisted thoracoscopy (VATS) and anterior mediastinal mass biopsy.
Diagnosis: Large B-cell lymphoma.
Immunohistochemical profile:
- Pan Cytokeratin (AE1/AE3): Negative
- CD13: Negative
- CD15: Negative
- CD10: Negative
- Cyclin D1: Negative
- MUM1: Negative
- TdT: Negative
- CD23: Negative
- CD11c: Negative
- EBV: Negative
- CD1a: Negative
- CD20: Positive
- CD19: Positive
- CD79a: Positive
- CD3: Positive in reactive cells
- CD99: Focally positive
- BCL6: Positive (>30%)
- BCL2: Positive (>50%)
- CD5: Positive in T-reactive cells
- PAX5: Positive
- Ki67: 70%-80%
Trichrome special stain shows fibrotic septa in the tumor. The morphology and the immunophenotype are suggestive of primary mediastinal large B-cell lymphoma (thymic origin).