Extranodal Rosai–Dorfman disease: a rare soft tissue neoplasm masquerading as a sarcoma

Introduction Rosai–Dorfman disease (RDD) is a rare proliferative histiocytic disorder of unknown etiology. RDD typically presents with generalized lymphadenopathy and polymorphic histiocytic infiltration of the lymph node sinuses; however, occurrences of extranodal soft tissue RDD may rarely occur when masquerading as a soft tissue sarcoma.