EXTRANODAL SOFT TISSUE ROSAI-DORFMAN DISEASE, A CHALLENGING DIAGNOSIS

Rosai-Dorfman disease (RDD) is a rare, benign histiocytic disease of unknown etiology. The characteristic presentation is lymphadenopathy due to abnormal production and accumulation of histiocytes in the lymph nodes. (1) Extranodal presentation may occur in rare instances in the soft tissue, posing a diagnostic dilemma to clinicians and radiologists alike.(2,3) Here, we report a case of a 56 year old lady of Indian descent, who presented with swelling on the left thigh which was clinically diagnosed as a soft tissue neoplasm. Histopathological examination revealed the classical features of RDD. There were large macrophages showing emperipolesis which were surrounded by dense lymphoplasmacytic inltrate. On immunohistochemistry, the histiocytes were positive for S100 and CD68. (4)The diagnosis of extranodal soft tissue RDD was thus conrmed.