OBJECTIVE: Authors characterized all published adult cases of cutaneous, intertriginous Langerhans cell histiocytosis (LCH) to bring this clinical presentation to the attention of clinicians. The authors emphasize the morphology, histopathology, immunohistochemical profiles, and genetic mutations associated with these cases. MATERIALS AND METHODS: A systematic review of the National Center for Biotechnology Information's PubMed was conducted, utilizing the following specific key words to identify all adult LCH patients with cutaneous intertriginous involvement: "Intertriginous Langerhans," "Vulvar Langerhans," "Genital Langerhans," "Perineal Langerhans," "Perianal Langerhans," "Intergluteal Langerhans," "Inguinal Langerhans," "Axillary Langerhans," and "Inframammary Langerhans." Reports were subjected to strict inclusion criteria: case reports, case series, or meta-analyses documenting case(s) of biopsy-proven LCH with cutaneous, intertriginous involvement in adult patients (>
18 years of age at the time of diagnosis). RESULTS: This systematic review identified 1 original and 121 published cases of biopsy-proven, cutaneous, intertriginous LCH in adult patients. Morphology commonly included eroded, ulcerated papules and plaques, and rare presentations demonstrated potential mimickers (hidradenitis suppurativa, deep fungal mycosis, condyloma accuminata). CONCLUSIONS: This systematic review encompasses the largest compilation of adult cutaneous intertriginous LCH cases in the medical literature to the authors' knowledge to date. This study identifies an important clinical presentation of this rare, commonly pediatric diagnosis
highlights trends among these cases and important clinical mimickers
and serves as a reminder to clinicians to maintain suspicion for LCH in adult populations, particularly in the setting of intertriginous cutaneous involvement.