H&E staining of sections of hilar lymph nodes.

(A) Typical tuberculous granulomas consisted of three parts, as shown at the box: the center of the granuloma displays evident necrosis and mineralization (*); numerous epithelioid cells and Langhans’ giant cells are present in the intermediate layer of the granuloma (†); A large number of lymphocytes are present in the external layer of the granuloma (‡). Magnification ×200. Box (*), Box (†), and Box (‡) indicate areas enlarged in panel B, C, and D, respectively. (B) Amorphous pink caseous material composed of the necrotic elements of the granuloma as well as the infectious organisms. Magnification ×400. (C) Epithelioid cells aggregation and Langhans’ giant cells could be seen subsequently. Magnification ×400. (D) Redundant lymphocytes infiltrated. Magnification ×400.