Cutaneous-to-Bronchial Rosai-Dorfman Disease without Lymphadenopathy: A Rare Case Report and Literature Review.

Rosai-Dorfman disease (RDD) is a rare non-Langerhans cell histiocytosis that typically presents with massive cervical lymphadenopathy and systemic manifestations. The cutaneous form is usually limited to the skin and rarely progresses to systemic involvement. Timely confirmation of the diagnosis of RDD in cases of progression to systemic involvement is a challenge for the health care system. We report a 23-year-old woman with a history of COVID-19 infection and subsequent mRNA vaccination who developed acneiform eruptions on her face and at the vaccination site on her shoulder. Biopsies confirmed cutaneous RDD without lymphadenopathy. After more than one year of a purely cutaneous course, she developed cough and dyspnea. Imaging revealed an isolated bronchial lesion without lymph node involvement; histology confirmed RDD. The patient responded to local corticosteroid injections and systemic glucocorticoids, with stabilization of the disease. Our report underscores the importance of considering RDD in persistent acneiform eruptions unresponsive to treatment and bronchial masses without lymphadenopathy.