title: Combined Cutaneous Rosai-Dorfman Disease and Localized Cutaneous Langerhans Cell Histiocytosis Within a Single Subcutaneous Nodule.
abstract: Rosai-Dorfman disease (RDD) is a reactive multisystem histiocytosis that typically presents with cervical lymphadenopathy and systemic symptoms. Cutaneous involvement occurs in approximately 10% of cases, and 3% of cases are limited to the skin without nodal or other extranodal involvement. Langerhans cell histiocytosis (LCH) is a clonal histiocytosis with a wide spectrum of presentations ranging from isolated skin or bone disease to multisystem involvement. Rare case reports have identified concomitant presentation of RDD and LCH; however, most of these reports have involved LCH and RDD occurring concurrently but at separate sites. We present a rare case of concurrent RDD and LCH presenting within a single skin nodule. The patient did not have any evidence of systemic involvement and has remained stable without additional treatment. We also review the literature on this unusual co-presentation and suggest possible underlying mechanisms. Finally, we recommend baseline laboratory and imaging studies and discuss treatment options based on the available evidence.
authors.affiliation: *Department of Dermatology, Saint Louis University School of Medicine, St. Louis, MO; †Departments of Dermatology and Pathology, Yale School of Medicine New Haven, CT; and ‡Department of Pathology, Saint Louis University School of Medicine, St. Louis, MO.
authors.forename: Brandon R
authors.initials: BR
authors.lastname: Litzner
authors.forename: Antonio
authors.initials: A
authors.lastname: Subtil
authors.forename: Claudia I
authors.initials: CI
authors.lastname: Vidal
mesh_terms: D002280:Basal Cell Carcinoma / Q000453:epidemiology; D015897:Comorbidity; D005260:Female; D006646:Histiocytosis, Langerhans-Cell / Q000150:complications* / Q000473:pathology; D015618:Histiocytosis, Sinus / Q000150:complications* / Q000473:pathology; D006801:Humans; D008875:Middle Aged; D012871:Skin Diseases / Q000150:complications* / Q000473:pathology; D012878:Skin Neoplasms / Q000453:epidemiology