<s>[INST] A 54-year-old man comes to the physician with a 3-month history of worsening fatigue, weight loss, and diffuse left upper quadrant abdominal pain. His temperature is 38.0°C. His laboratory results are as follows:

- White blood cell count (WBC): 15,000 cells/μL
- Hemoglobin: 10.5 g/dL
- Platelet count: 450,000 cells/μL
- Blood glucose: 120 mg/dL
- Serum creatinine: 1.2 mg/dL
- Total bilirubin: 1.5 mg/dL
- Alkaline phosphatase: 120 IU/L
- Alanine transaminase (ALT): 60 IU/L

A CT scan of the abdomen shows a 10-cm solid mass in the spleen with multiple smaller satellite lesions. The mass is highly suggestive of a primary splenic tumor. Given the clinical presentation and the laboratory results, what is the most likely diagnosis?[/INST]