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. MATERIALS AND METHODS: A comprehensive search of all published cases of soft tissue RDD without associated lymphadenopathy was conducted using PubMed and Google Scholar for the years 1988 to 2011. Ophthalmic RDD was excluded. RESULTS: Thirty-six cases of extranodal soft tissue RDD, including the current one, have been reported since 1988. Anatomical distribution varied among patients. Four (11.1%) patients presented with bilateral lesions in the same anatomic region. Pain was the most common symptom in six (16.8%) patients. Sixteen (41.6%) patients were managed surgically, of which one (2.8%) case experienced recurrence of disease. CONCLUSION: RDD is a rare inflammatory non-neoplastic process that should be considered in the differential diagnosis of a soft tissue tumor. Thus, differentiation of extranodal RDD from more common soft tissue tumors such as soft tissue sarcoma or inflammatory myofibroblastic tumor is often difficult and typically requires definitive surgical excision with histopathological examination. While the optimal treatment for extranodal RDD remains ill-defined and controversial, surgical excision is typically curative.