Immunophenotype of LyGa by immunohistochemistry. The atypical cells are positive for CD7 (A; case 5), CD56 (B; case 3), granzyme B (C; case 4), and cytoplasmic CD3ϵ (D; case 2). To confirm the cytoplasmic localization of CD3ϵ, fluorescein double immunohistochemistry for CD3ϵ (E) and CD56 (F) was performed (case 10). In the merged figure (G), the cytoplasmic localization of CD3ϵ is clearly shown, indicating that the atypical cells are of NK lineage. Figures were taken with a microscope (BX51; Olympus) and a digital camera (KY-F75; Victor). Microsoft PowerPoint 2007 was used for image processing. Numeric apertures: 40× (A,C,D), 10× (B), 60× (E-G).