Hepatic fibrin-ring granulomas in granulomatous hepatitis: report of four cases and review of the literature

BACKGROUND The differential diagnosis of hepatic fibrin-ring granulomas includes infective agents (Coxiella burneti, CMV, EBV,....), hypersensitivity to medication (allopurinol) and malignancy. METHODS During a period of 6 months, four patients presented at our university hospital with a similar clinical picture of fever and abnormal liver tests, and fibrin-ring granulomas on liver biopsy. Clinical course, laboratory and imaging findings, and histopathological features were compared. RESULTS Clinical manifestations, and laboratory and imaging findings were similar. Histopathological assessment of the hepatic fibrin-ring granulomas appeared not to be helpful in identifying the causative agent. Other histopathological features (e.g. sinusoidal rows of lymphocytes, eosinophilic polymorphonuclear infiltrate) were suggestive for the causative agent, yet conclusive identification was obtained by either serology (Q fever, CMV, EBV), or by exclusion with concomitant stop of medication (allopurinol). CONCLUSIONS In the differential diagnosis of hepatic fibrin-ring granulomas, serologic titers remain the determining factor, since an infective agent is the most common cause. When hepatic fibrin-ring granulomas are present, other histopathological features may be helpful in making the differential diagnosis.