Case 41. Reference case 41B

　 　 　 　
　 Infectious mononucleosis, showing epipharyngeal swelling in a 10 year-old boy (biopsy, HE). 　
　 　 　 　

　

 　 In the non-necrotic part of the epipharynx, activated atypical lymphocytes are intermingled with small lymphocytes.