An 82-year-old male was transferred for an abdominal CT scan for chronic cutaneous fistulation at the level of the right abdominal wall. Previous CT and ultrasound imaging described recurrent collections in the right abdominal wall, requiring CT guided abscess drainage. The abdominal CT scan revealed an abscess in between the internal oblique and transversus abdominis muscle layers of the right flank, with significant fat stranding and loss of the intermuscular fat planes ( Figure 1 ). Inside this abscess, we notice a spontaneous hyperdense nodular lesion (Hounsfield Units 130), which doesn't enhance after contrast injection ( Figure 1 arrow). Looking back at the previous CT scans we discern the presence of this hyperdense lesion, which tends to migrate over time over a small distance along the abdominal wall ( Figure 2 A-D arrow). We can trace this back on the numerous previous scans, with different local tissue reactions over time. The first performed CT 8 years prior reveals a perforated calculous cholecystitis, containing multiple cholecystolithiases with the same density as our previously mentioned hyperdense lesion ( Figure 3 arrow). Thus, raising the suspicion of a biliary origin of this corpus alienum.
Teaching point: Spilled gallstones during laparoscopy may lead to late abscess.