Uncommon condition mimicking non-resolving pneumonia and malignancy on radiography that improves dramatically with a course of steroids.

A 58-year-old man was seen in a specialist respiratory clinic, with non-resolving pneumonia. Various investigations including CT scan, bronchoscopy and CT-guided biopsy were carried out for suspected malignancy but they could not find any evidence of neoplasia or anything else of significance. The lung mass that persisted for years later resolved with a course of steroids, at which point further investigations for alternative differential diagnoses suggested a surprising conclusion. 2016 BMJ Publishing Group Ltd.