Rosai-Dorfman Disease of Right Atrium Mimicking Myxoma

Autopsy case of Rosai-Dorfman disease presenting as fibrinous pericarditis

Rosai-Dorfman disease (RDD) is a rare non-Langerhans cell histiocytosis that is characterized histopathologically by accumulation of CD68-positive, S100-positive, and CD1a-negative histiocytes. Cardiac involvement of RDD is rare. We report here an autopsy case of cardiac involvement of RDD presenting as fibrinous pericarditis. A 14-year-old Japanese boy complained of loss of appetite and breathing difficulty when lying down. He was found dead on his back in his bedroom. One year before his death, he was diagnosed with RDD after skin biopsy. At autopsy, the deceased was 153 cm in height and weighed 38 kg with systemic edema. He had flat pigmented light-brown spots, as well as many pale reddish-brown papules on the abdomen and both thighs. Cervical and mediastinal lymphadenopathy was observed. A large amount of pleural and ascitic fluid was observed. The spleen weighed 381.9 g and showed splenomegaly. The heart weighed 620 g and showed acute fibrinous pericarditis with adhesion. Abundant fibrin was observed on the epicardial surface. The infiltrating cells were CD68-positive, S100-positive, and CD1a-negative histiocytes. The skin and spleen showed histiocytic involvement. Systemic edema, large amounts of pleural and ascitic fluid, a high brain natriuretic peptide level in blood, and hemosiderin-laden macrophages in the lungs suggested chronic heart failure. We speculate that the cause of death was extranodal cardiac involvement of RDD with chronic heart failure. This case highlights the need for forensic pathologists to perform a complete autopsy to determine the cause of sudden death when cardiac involvement of RDD is present.

Extranodal Rosai-Dorfman Disease Presenting as a Mediastinal Mass with Pulmonary Artery Invasion

Rosai–Dorfman disease (RDD) is a rare, nonmalignant disorder of histiocyte proliferation typically involving the cervical lymph nodes. However, a subset of patients with RDD will display extranodal manifestations that are highly variable in presentation, more challenging to diagnose, and less likely to spontaneously regress compared to nodal disease. While case reports of extranodal involvement in nearly every organ system exist, documented instances of mediastinal and pulmonary artery involvement are particularly rare. This study describes the case of a middle-aged woman presenting with new onset right heart failure who was found to have extranodal RDD in the form of a large mediastinal mass with invasion and occlusion of the main pulmonary arteries.