Inflammatory pseudotumor of the liver successfully treated with nonsteroidal anti-inflammatory drugs: a challenge diagnosis for one not so rare entity.

Inflammatory pseudotumor of the liver is a rare, benign lesion characterized by a well-circumscribed mass of chronic inflammatory cell infiltration and proliferating fibrous tissue. Its etiology remains unclear, although inflammatory processes have been proposed. It is often misdiagnosed as a malignant tumor, and the management has been traditionally surgical. We report the case of a 16-year-old boy who was referred from another hospital with a fever of >38 degrees C with rigor and right upper quadrant pain which he had suffered from for 5 days. The ultrasonographic computed tomography and MRI findings were not diagnostic, and we performed a needle biopsy from the lesion that was consistent with inflammatory pseudotumor (of liver, mixed fibrous tissue and chronic inflammatory cell infiltration). The patient was treated with nonsteroidal anti-inflammatory drugs and had an uneventful clinical course. During follow-up, the lesion subsequently shrank to completely vanish 1 year later.