A Case of Rosai-Dorfman Disease Presenting as an Isolated Pleural Plaque

Rosai-Dorfman disease (RDD) is a rare non-Langerhans histiocytic disorder primarily involving lymph nodes. Extranodal RDD has heterogenous presentation, and isolated pulmonary involvement rare. We report the only case of presenting as an pleural mass. Our patient was 55-year-old female with multiple comorbidities who presented chest pain. Imaging revealed enlarging pleural-based lesion. She underwent resection mass, showing atypical infiltrate in prominent background collagenous fibrosis. Immunohistochemistry shows CD1a-negative S100-positive cells demonstrating emperipolesis, confirming diagnosis RDD. currently on six-month CT surveillance no recurrence disease. This highlights unique presentation It also underscores that observations may be appropriate asymptomatic cases.