Background: Inflammatory pseudotumours are rare benign tumours that can present as solid and potentially malignant tumours on diagnostic images.
Case description: A 59-year-old male presented at the emergency department with continuous pain in his right upper abdomen, attacks of colic and intermittent fever. CT scans of the abdomen revealed a solid lesion in the liver. Histopathological analysis of a biopsy showed an inflammatory pseudotumour. Since the pain persisted and a malignancy could not be excluded with certainty, surgical resection of the tumour was performed. The specimen showed an inflammatory pseudotumour with an increase in IgG4 positive plasma cells as well as a purulent infection around aggregates of Actinomyces.
Conclusion: It is important to realise that a pseudotumour caused by an inflammatory reaction can mimic a malignancy.