Cryptococcomas contain numerous granzyme B positive, but very few perforin positive NK cells.

<p>Case 1: The brain was removed at autopsy and fixed in formalin with subsequent sectioning and examination. Sections were taken from the cryptococcoma in the cerebral cortex and stained with mucicarmine (200×) (A); or stained with PAS and labeled with either anti-CD56 (400×) (B); anti-CD57 (600×) (C); anti-granzyme B (1000×) (D); or anti-perforin (E, 600×) antibody. <i>Cryptococcus</i> (open arrow) in association with labeled cells (solid arrows) are shown. Perforin positive cells (brown) in NK cell lymphoma in lung, shown as a positive control for perforin (F). Case 2: Wedge resection of lung cryptococcoma, fixed in formalin with subsequent sectioning, PAS staining and labeled with either anti-CD57 (G, 400×), anti-granzyme B (H, 1000×) or anti-perforin (I, 600×). No organisms are present in figure G. The organisms stain bright pink with PAS, whilst positive staining for antigens is dark brown.