Rosai-Dorfman disease with a concurrent mantle cell lymphoma

Rosai-Dorfman disease (RDD), also known as sinus histiocytosis with massive lymphadenopathy (SHML), is a rare, benign histiocytic disorder characterized by generalized lymphadenopathy and constitutional symptoms.1 The classic presentation of RDD is painless cervical lymphadenopathy with associated fever, night sweats, and weight loss.2 Extranodal involvement is present in up to 40% of cases of RDD, with the skin being the most common site.1 Although considered benign, 10% of patients with RDD have coexisting immunologic abnormalities, such as postinfectious conditions and hematologic malignancies.