Microdissection and mutational analysis of a representative patient with NLPHL. (A) Lymph node biopsy showing a neoplastic nodule containing characteristic L/H cells with popcorn appearance of the nucleus (top left, hematoxylineosin stain; magnification, 800 ×). (Top middle, immunoperoxidase technique; magnification, ×150. L/H tumor cells are CD20⁺ (arrows) and are surrounded by a rim of CD20^– rosette T cells (top right, immunoperoxidase technique; magnification, 800 ×). CD20⁺ L/H cells before and after laser microdissection (bottom, right and left) (APAAP technique). *CD20⁺ tumor nodule. (B) Electropherogram showing mutations of the RhoH/TTF and PAX5 genes in microdissected L/H cells (Table 2, patient 2).