Rosai-Dorfman Disease in a Middle-Aged Man With Recurrent Pleural Effusions and Lymphadenopathy.

Rosai-Dorfman disease (RDD) is a rare benign condition that presents most commonly with lymphadenopathy and skin lesions and is characterized by infiltration of histiocytes into the skin and soft tissues. We present a case of RDD in an Afro-Caribbean male in his 50s who presented to our chest clinic with shortness of breath, cough, and weight loss of 15 kg over one year. CT scan showed evidence of right pleural effusion, mediastinal and hilar lymphadenopathy, and bony lesions in the spine. Cytology from multiple pleural effusions and endobronchial ultrasound-guided fine needle aspiration from lymph nodes did not show any malignancy. Left axillary excisional biopsy showed a pattern consistent with RDD. The patient was started on interferon therapy by the hematologist and pleurodesis after repeated pleural taps failed to relieve recurrent right pleural effusions. This case emphasizes the importance of tissue diagnosis to avoid misdiagnosis and unnecessary treatment.