Case 370:   Abscess (amebic)

Diagnostic Category:

Clinical Presentation:

39 year old man returning from a 3 year bike trip around the world (34.000km) and presenting with fevers (39.3°C), arthralgias, and chest and right abdominal pain. GOT (ALT) 130, GPT (AST) 156, AP 147 (<130nl), CRP >200, HB 13.9 (14.4 – 17.5g/dl), WBC 14.400 (neutrophils: 11.990, lymphocytes 950).

CT: Minimally hyperdense debris and double rim sign

Imaging Findings:

Unenhanced CT demonstrates a hypodense avascular mass in segment 7 representing amebic abscess, with thin enhancing capsule surrounded by thicker hypodense rim, representing edema, best seen on portal venous out phase ("double rim sign").

Absent surrounding hypervascularity of surrounding hepatic parenchyma, which was well seen on contrast enhanced ultrasound of the same day (see US) may be due to suboptimal early arterial contrast timing.

The CT exam was performed 5 days after initiation of treatment with metronidazole.