Histologic and immunocytochemical features of posttransplantation HHV8-related neoplastic diseases. (A) Top panel: KS. Hematoxylin and eosin–stained section of a skin lesion characterized by typical “spindle-like” neoplastic cells and surrounding “slit-like” vascular spaces (original magnification ×200). Bottom panel: On contiguous section from the same skin biopsy, LANA-1 immunostaining demonstrated HHV8 latent infection in the neoplastic spindle-like cells, within the KS lesion (original magnification ×200). (B) PEL: cytospin preparation from pleural effusion, showing a massive aggregate of neoplastic lymphoid cells with 2 evident mitotic figures. May-Grünwald-Giemsa stain typically revealed immunoblastic cells with dark basophilic cytoplasm and anaplastic cells with prominent scant light staining basophilic cytoplasm (original magnification ×600). (C) MCD: LANA-1 immunostaining in lymph node biopsy showing typical MCD-associated pattern, with positive plasmablastic B cells surrounding the follicular center (original magnifications ×100 and ×200).