Case Presentation:

A 24‐year‐old man with no medical history presented with 2 weeks of intermittent night sweats and 2 days of crampy right upper quadrant abdominal pain without other associated symptoms. He denied any history of travel outside the United States. He did have tattoos but denied any drug use, blood transfusions, or incarceration. Physical exam was remarkable for fever to 101.3 degrees, tenderness in the right upper quadrant and a palpable liver edge 3 cm below the costal margin. Initial laboratory analysis revealed normal white blood cell count and liver function tests and negative tests for hepatitis A, B, and C, and HIV. ACT scan of the abdomen revealed 2 masses, an approximately 3‐cm lesion in the right hepatic lobe and an approximately 6 cm lesion in the left hepatic lobe. An MRI suggested these masses were compatible with metastatic lesions but was not definitive. A core biopsy of the lesion in the right lobe was obtained and showed necrotic debris and caseating granulomas. An infectious etiology was assumed, however stains for fungal organisms and mycobacteria were negative. Microbiologic cultures‐including routine bacterial, fungal, and mycobacterial—were negative. Urine histoplasma, Blastomyces, and coccidiodes antigens were negative. Serum serologies for Brucella, Leptospira, and Entamoeba were negative as was a serum cryptococcal antigen. A second biopsy was performed and demonstrated spindle cells and focal necrosis consistent with fibrohistiocytic type inflammatory pseudotumor of The liver. Repeat MRI performed 3 weeks later demonstrated regression of the lesions and surgical intervention was deferred.

Discussion:

Inflammatory pseudotumors (IPTs) represent a collection of rare, benign inflammatory masses that can be found throughout The body. IPT of the liver usually presents with fever, abdominal pain, and fatigue. It commonly affects young male patients. It has been increasingly identified as a cause of focal liver lesions, with a reported incidence of 1% among patients undergoing liver resection. The etiology is unknown, but an inflammatory reaction to translocation of gut flora and an autoimmune response have been hypothesized. Imaging characteristics on CT and MRI can be nonspecific and often appear similar to malignant lesions. Many cases of IPT of the liver have a possible antecedent cause, such as international travel, biliary or pancreatic disease, and Gl infection. Management is controversial and can involve surgical resection, antibiotics, and steroids. A recent review of the literature demonstrated no difference in overall mortality between patients treated surgically and medically.

Conclusions:

IPT of the liver should be considered in the differential diagnosis of focal liver lesions, particularly among young patients with associated abdominal pain and constitutional symptoms.

Author Disclosure:

M. Fitzpatrick, none; J. Butter, none; L. Kuo, none.