Erdheim-Chester Disease is a rare, xanthogranulomatous, non-Langerhans-cells histiocytosis with frequent systemic involvement. Although the diagnosis is based on characteristic histological and radiological findings, its identification can be challenging because of its heterogeneous presentation. 

This case shows a rare pulmonary manifestation of Erdheim-Chester disease (ECD). The patient complained of chest tightness, shortness of breath. Also, perirenal involvement was present; although blood values of creatinine and eGFR were normal.

Retroperitoneal biopsy-proved diagnosis of ECD and histiocytosis BRAF V600 mutation was reported. First-line treatment with sirolimus and vemurafenib was started.