Abstract
Erdheim-Chester disease is a rare clonal non-Langerhans cell histiocytosis with multisystemic involvement. It affects bones, large vessels, and retroperitoneum. Cardiac involvement is one of the main mortality predictors.(1) We present an unusual case that debuted with cardiac tamponade and pericardial constriction requiring pericardiectomy for definitive control. (Level of Difficulty: Intermediate.).