A 78 year-old man presents to your office and reports fatigue, fever, weight loss and night sweats for the last few months. He ignored his symptoms for a while but his wife insisted he must go to the doctor. Two weeks ago he had an insect bite and his ‘skin reacted badly like never before’. Physical examination is significant for cervical, axillary and inguinal lymphadenopathy. Abdominal examination found hepatomegaly and splenomegaly. Which of the following is the most likely diagnosis in this patient?
