Fig. 5

Histopathological findings of the mediastinal mass showing small- to medium-sized atypical lymphoid cells, and some of them exhibit plasmacytoid differentiation in the hematoxylin and eosin staining (a). A light chain restriction positive for kappa (b) and negative for lambda (c) chains is demonstrated. We used antibodies with the product number N1510 (company, DAKO; dilutions, 5 times for the kappa chains) and product number NCL-LAM (company, Leica; dilutions, 200 times for the lambda chains). The positive cells are stained with a brown color