OBJECTIVETo study the clinicopathologic features and differential diagnosis of extranodal Rosai-Dorfman disease (RDD) of the upper respiratory tract.

METHODSThe clinical, pathologic and immunohistochemical features of 10 cases of RDD were evaluated.

RESULTSAmong the 10 cases studied, there were 3 males and 7 females. The age of patients ranged from 20 to 61 years old (mean 38 years). The lesion arose in the nasal cavity (7 cases), nasopharynx (2 cases) or hard palate to trachea (1 case). Most of the patients presented with nasal obstruction, rhinorrhagia or tumor mass in the nasal/nasopharyngeal regions. CT scan often showed the presence of soft tissue lesion without bone destruction. Histologically, extranodal RDD was characterized by light-staining bands alternating with dark-staining bands. The light-staining bands were formed by aggregates of large round or polygonal histiocytes with emperipoiesis. The dark-staining bands were formed by abundant lymphoplasmacytic infiltrates. Immunohistochemical study showed that the histiocytes strongly expressed S-100 protein and partially expressed CD68. Six patients had no recurrence after surgical resection.

CONCLUSIONSExtranodal RDD of the upper respiratory tract is a rare disorder of histiocytic proliferation, which usually involves the nasal cavity and paranasal sinuses. RDD can easily mimic rhinoscleroma, mainly due to the overlapping morphologic appearance. Immunohistochemical study is helpful in the differential diagnosis.