Review Question - QID 210477

A 47-year-old man presents to the emergency department with worsening weakness in the setting of persistent abdominal pain. He arrived in the United States 6 months ago and has been working in a restaurant as a cook. His abdominal pain started 4 months ago, but he could not find time away from work to see a doctor. He reports nausea without vomiting. His temperature is 98.6°F (37°C), blood pressure is 98/61 mmHg, pulse is 110/min, and respirations are 18/min. He has no cardiac murmurs but does have tenderness in his epigastric region. His hemoccult test is positive. His laboratory workup is below.

Hemoglobin: 7.2 g/dL
Hematocrit: 23%
Leukocyte count: 11,000/mm^3 with normal differential
Platelet count: 470,000/mm^3

Serum:
Na+: 137 mEq/L
Cl-: 109 mEq/L
K+: 3.1 mEq/L
HCO3-: 23 mEq/L
BUN: 52 mg/dL
Glucose: 89 mg/dL
Creatinine: 0.9 mg/dL

An esophagogastroduodenoscopy reveals the presence of a mass surrounded by bleeding ulcers. On initial shave biopsy, the preliminary diagnosis is mucosa-associated lymphatic tissue lymphoma (MALToma). Which of the following is the most appropriate next step in management?