Respiratory tract involvement in Rosai-Dorfman disease - A report of two distinct cases.

Rosai-Dorfman Disease (RDD), a rare histiocytic disorder typically characterized by painless cervical lymphadenopathy, can occasionally present extranodal presentations. Here, we report two distinct RDD cases involving the respiratory system, both treated with interventional bronchoscopy resection. The first case involved a solitary tracheal neoplasm with wild-type KRAS (Kirsten rat sarcoma viral oncogene homolog). This patient showed no recurrence or metastasis over a 16-month follow-up period. In contrast, the second case displayed multiple tracheal neoplasms with KRAS mutation. While there was no in situ recurrence at the resected site, the untreated tracheal lesions initially progressed at the first four months of follow-up but remained stable at the ten-month follow-up. These cases illustrate the variability and potential progression of RDD, and highlight the promising application of bronchoscopic treatment for managing respiratory involvement in RDD.