Thymic Hyperplasia after Lung Transplantation Imitating Posttransplant Lymphoproliferative Disorder
Figure 2
(a) Thymic tissue with adjacent mature fat (hematoxylin and eosin, original magnification ×4). (b) Hyperplastic thymus with lobular structure, divorcing fibrous septa, sometimes interrupted by mature fat and enclosed hyperemic vessels (hematoxylin and eosin, original magnification ×4). (c) Thymic tissue with prominent enlarged Hassall’s corpuscles (hematoxylin and eosin, original magnification ×20). (d) Immunohistochemistry shows CD20 positivity for B lymphocytes surrounding Hassall’s corpuscles (original magnification ×20, methylen blue counterstain). (e) Strong Ki-67 positivity, which demonstrates the high proliferation rate of the cellular elements of thymic tissue. The staining relieves the areas surrounding the Hassall’s corpuscles (original magnification ×4, methylen blue counterstain).
