ABSTRACT
To report a case of sinus histiocytosis with massive lymphadenopathy [Rosai-Dorfman disease] in an extranodal site with unusual presentation. A 19-year-old girl presented with bilateral upper eyelid swellings of 2 years duration due to tumor. The masses were excised and sent for histopathological examination. Microscopic examination revealed similar features in both masses in the form of a collection of large histiocytic cells showing emperipolesis [lymphocytophagocytosis]. The histiocytic cells stained positively with S-100 protein and CD68. The background comprised small lymphocytes and plasma cells. Based on the overall features a diagnosis of sinus histiocytosis with massive lymphadenopathy or Rosai-Dorfman disease was made. The present case highlights one of the forms in which extranodal Rosai-Dorfman disease can manifest itself. It is important to keep this differential diagnosis in mind whenever such histopathological features are encountered