We report a case of Rosai-Dorfman disease with typical cytological features of the lymph node confirmed by imprint smear, which showed numerous plasma cells and large histiocytes containing nondegenerated blood cells. Immunohistochemically, histiocytes were positive for S-100 protein. Histologically, follicles were decreased and histiocyte filling was noted in the expanded lymphatic sinus. Emperipolesis was also noted. Rosai-Dorfman disease is diagnosed by the presence of emperipolesis in large histiocytes, considerable plasma cell infiltration, and positive S-100 protein presence in histiocytes confirmed by imprint smear.
We report the case of an 80-year-old ex-coal miner under follow-up for colonic carcinoma who presented with mediastinal lymph node swelling. A specimen obtained through endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) contained histocytoid cells containing abundant amounts of phagocytosed coal pigment. Examination by polarized microscopy demonstrated birefringent silica and silicate crystals, both in the cytoplasm of the cells and in the background. No cancer cell clusters were found in the aspirate. EBUS-EBNA is a less invasive diagnostic method suitable for evaluating mediastinal lymph node swelling in silicosis patients.