Lung and liver sarcoidosis-like reaction induced by tocilizumab.

A drug-induced sarcoidosis-like reaction is a systemic granulomatous reaction indistinguishable from sarcoidosis and occurring in temporal relationship with a drug initiation. In this article, we report a patient who developed lung and liver granulomatous lesions following tocilizumab initiation for a giant cell arteritis. Infectious, toxic, neoplastic and inflammatory differential diagnoses were ruled out and lesions regressed after treatment cessation, leading to the diagnosis of tocilizumab induced sarcoidosis-like reaction. We review the 6 cases reported so far and emphasize the value of a prompt diagnosis. Finally, we discuss the potential pathophysiological mechanisms underlying this rare reaction, which could help to better understand the pathophysiology of sarcoidosis.