A Swollen Painful Knee In An Elderly Man With Recently Diagnosed Acute Myelogenous Leukemia

Gross and Microscopic Histologic Finding Under aseptic conditions, 18.0 mL of turbid fluid was aspirated from the left knee. Microscopically, no crystals were detected under polarized light. Gram stain and microbial cultures were negative. The WBC and RBC counts were 3,285/mm3 and 360/mm3, respectively. However, atypical mononuclear cells were identified on light microscopy [I2]. Flow cytometric immunophenotyping of synovial fluid cells from our patient was performed with the results shown in I3. Questions: 1. What is the interpretation of this patient’s flow cytometric immunophenotyping results? 2. Based on the constellation of this patient’s clinical and laboratory findings, what is the most likely diagnosis? 3. Which age group is most commonly affected by this patient’s condition or disorder? 4. What is the usual clinical presentation of this patient’s condition? 5. What is the pathogenesis of this patient’s condition? 6. What is the preferred diagnostic test for establishing the diagnosis of this patient’s condition? 7. What is the best therapy for this patient’s disorder?