A Quiet Invasion

A 45-year-old man born in Oaxaca, Mexico presents to the emergency department with three weeks of progressive right upper quadrant pain, fevers, and an unintentional weight loss of five kilograms. He immigrated to the United States fifteen years ago and returns to visit family in rural Oaxaca each summer; his most recent trip ended seven weeks ago. He reports no significant diarrhea. He takes no medications and has no prior medical history.

On examination, temperature is 38.7°C, heart rate 98, blood pressure 118/74 mmHg. He appears chronically ill. There is marked tenderness to palpation in the right upper quadrant and the liver edge is palpable 4 cm below the right costal margin. No jaundice. No splenomegaly. No peritoneal signs.

Laboratory studies: WBC 15.4 k/mcL with 88% neutrophils, hemoglobin 11.8 g/dL, platelets 388 k/mcL. Alkaline phosphatase 224 U/L, total bilirubin 1.6 mg/dL, AST 58 U/L, ALT 64 U/L, albumin 2.9 g/dL. Creatinine 0.9 mg/dL. Blood cultures are drawn and remain negative at 48 hours. CT of the abdomen with contrast reveals a single 9 cm hypodense, rim-enhancing lesion in the right lobe of the liver. A diagnostic aspirate is performed and the fluid is described as chocolate-brown and odorless, with no organisms on Gram stain and negative bacterial culture. The image below was obtained from the lesion aspirate.