Extranodal rosai-dorfman disease: Clinicopathologic series of 10 patients with radiologic correlation and review of the literature

Objectives: To describe the radiologic and clinicopathologic features of extranodal Rosai-Dorfman disease (RDD) in our patient population. Methods: Via a data mining engine, we evaluated 13 cases of extranodal RDD in 10 patients treated at our institution from 2000 to 2014. Results: There was a marked female predominance (90%) in our series. The most common clinical presentation was a palpable, painless mass, which often simulated a neoplasm. Only two cases occurred in children. Multicentric and recurrent disease were uncommon. Histologically, all cases showed large histiocytes with emperipolesis in a mixed inflammatory background, with areas of dense, storiform collagen fibrosis. Positive S-100 and CD68 with negative CD1a in histiocytes are characteristic. Conclusions: Extranodal RDD is rare and its manifestations varied. It may constitute a clinical and pathologic diagnostic challenge. Clinical suspicion and recognition of its histologic features are necessary for correct diagnosis and avoiding unnecessary treatment. Resection is curative in most cases.