Exuberant granulomatous reaction masking primary mediastinal seminoma.

Primary mediastinal seminoma is an important diagnostic consideration for an anterior mediastinal mass in a young man. Occasionally, seminomas can elicit a florid granulomatous reaction that can obscure the underlying tumour on a small biopsy like the one obtained with a core needle from an anterior mediastinal mass. Herein, we illustrate such a scenario, which can lead to diagnostic confusion if this association is not recognised.