Benign histiocytosis: Rosai-Dorfman disease

BACKGROUND:Sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease (RDD)) is a rare entity with pathological accumulation of specific, activated macrophages, mainly in cervical lymph nodes. However, in half of patients its primary presentation is extranodal. Its aetiology is unclear; several clues point in an immunological direction. Common clinical presentation is massive cervical lymphadenopathy, but nearly half of all patients suffer from extranodal manifestation at very diverse localizations. Diagnosis is based on histopathological findings: emperipolesis and S-100 positive histiocytes. Taking into account its benign character, caution in implementing therapy is recommended. Therapeutic options are limited to specific situations only.CASE DESCRIPTIONS:Two patients with known RDD presented at our outpatient clinic. A 75-year-old woman with two tumours in her right breast and an 83-year-old man with constipation - most likely due to a kidney tumour. Microscopic findings finally confirmed extranodal manifestation of RDD.CONCLUSION:Extranodal manifestations of RDD present in various forms and on history taking, physical examination and radiological imaging may resemble malignancies