**2.4.3 Inflammatory pseudotumor**

Inflammatory pseudotumor of the liver is a benign reactive process, the pathogenesis of which is unclear. In the majority of cases in the literature, an infectious agent was found to be the causative agent. Symptoms, when present, are generally nonspecific including body pain, fever, weight loss, leukocytosis, and elevated transaminases. CT findings are generally not specific for the diagnosis, although spontaneous regression on followup imaging in 4-6 weeks is commonly reported to occur (Seki, S et al 2004). Histological features include replacement of liver parenchyma by densely hylanized collagenous tissue and chronic inflammatory infiltrates. These features are missed on FNA, making core needle biopsy critical for accurate diagnosis (Tsou, YK et al 2007). In a review of eight cases, Tsou et al have suggested that inflammatory pseudotumor may best be thought of as a variant of a healing liver abscess. Thus, treatment consists of antibiotic therapy and nonsteroidal antiinflammatory drugs. With appropriate therapy, the lesion can be expected to spontaneously regress. Surgical therapy is thus reserved for cases with severe symptoms or when malignancy is unable to be reliably excluded.
