“…We read with great interest the Clinicopathologic Conference by Los Arcos‐Bertiz et al published recently in Arthritis Care & Research about a patient with Erdheim‐Chester disease (ECD) who was treated effectively with interferon‐α (). Of note, the prognosis of this condition is poor, with 1‐ and 5‐year survival rates of 96% and 68%, respectively, because of resistant and progressive life‐threatening ECD, and interferon‐α can be responsible for a wide range of adverse events and potentially severe toxicities ().…”