A 65 year old man presents with debilitating fatigue and some weight loss. On exam, you note hepatomegaly and splenomegaly. The spleen is pretty remarkable; you feel the inferior border at the pelvic brim and the right border past midline. His past medical history includes a DVT when he had a knee replacement. Otherwise, he's pretty healthy. However, labs are surprising. Hemoglobin is 9g/dL, WBC is 26,000/microL, platelets are 90,000/microL.
Peripheral blood smears are shown below:
You attempt to do a bone marrow aspiration but get a "dry tap." A bone marrow biopsy is shown below; the trichrome stain colors collagen blue.
Challenge: What's your diagnosis?
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