Hepatic involvement in granulomatosis with polyangiitis - diagnostic difficulties.

We report the case of a 57-year-old Caucasian man who presented with dry cough, haemoptysis, fever, lung nodules, erythrocyturia, and acute hepatitis. After a lung biopsy, the patient was diagnosed with granulomatosis with polyangiitis. The diagnosis was supported by the presence of anti-proteinase-3 anti-neutrophil cytoplasmic antibodies. The most common causes of liver damage are excluded. The patient was treated with prednisone and cyclophosphamide, which resulted in remission of chest CT findings and improvement in liver function tests. During the flare, new lung infiltrations as well as elevation of liver enzymes were present. Treatment with rituximab resulted in complete clinical and radiological remission and normalisation of liver function tests. What makes this case worth reporting is the rare liver involvement in the GPA. After exclusion of coexistence of autoimmune liver disease and drug-induced liver lesion, organ involvement was supported by the reversion of abnormal LFT after the immunosuppression of GPA.