Sinus histiocytosis with massive lymphadenopathy--a review of seven cases.

Sinus histiocytosis with massive lymphadenopathy (SHML) also called as Rosai Dorfman disease is a rare histiocytic proliferative disorder of unknown etiology. Histological features currently define it. Persistent painless lymphadenopathy due to expansion of sinuses infiltrated with benign histiocytes and plasma cells and emperipolesis are the characteristic features of SHML. Our study includes seven cases (5 nodal and 2 extranodal) of SHML over a 5-year period whose slides and blocks were reviewed. IHC was performed on the main lesion, from a panel of S100, CD68, LCA, CD20, CD3, CD30, CD43, bcl2, cytokeratin and epithelial membrane antigen. In our series we have work up available in 7 cases out of which a detailed follow-up is available in 5 patients. Out of these 5 patients, 4 have a stable disease, while one developed histiocytic sarcoma after a gap of four years.