A 50-year-old man presenting with complaints of severe fatigue and excessive tiredness from past 6 months. His fatigue has been worsening over the past 4 weeks. He is also having non-productive cough from past 15 days, and has experienced several episodes of drenching night sweats. Clinical examination reveals several large bruises on his extremities without any obvious external injuries. Abdominal examination reveals massive enlargement of both the liver and spleen. There was no detectable lymphadenopathy. Laboratory findings of this patient is given below:
WBC count: 1000/mm3
Neutrophils: 50%
Eosinophils: 5%
Lymphocytes: 40%
Monocytes: 0%
Basophils: 5%
RBC count: 3.4/mm3
Hemoglobin: 8 mg/dL
Platelet count: 15,000/mm3
Peripheral blood smear was seen as given in image. Which of the following is the most likely diagnosis?
a) Acute lymphocytic leukemia
b) Hairy cell leukemia
c) Infectious mononucleosis
d) Nodular sclerosing Hodgkin’s lymphoma