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Adult vulvar Langerhans cell histiocytosis: a rare presentation

Dear Editor, We report a case of Langerhans cell histiocytosis (LCH) manifesting as vulvar ulceration and diabetes insipidus (DI). LCH is a rare monoclonal proliferative disorder of Langerhans cells, which has an unclear etiology. It can be confined to a single organ or have systemic involvement. In adults, LCH often affects the bones, especially the axial skeleton. Less commonly, the pituitary gland is involved. DI is the initial manifestation in 25% of patients with LCH, far more frequently in children than in adults, caused by Langerhans cell infiltration into the hypothalamus, pituitary stalk, or posterior pituitary. DI is often associated with multisystemic LCH. Vulvar ulceration as the only cutaneous manifestation of LCH is extremely rare. A 42-year-old Caucasian female patient with a 4-year history of DI was referred due to recurrent vulvar ulcers developing in the preceding 2 years. On physical examination, there were multiple exudative ulcers and erosions, well-defined with irregular borders, measuring 0.5–2.5 cm, covered by a layer of adherent fibrin, on the labia minora and the posterior fourchette (Fig. 1). No other mucocutaneous lesions were observed. Polymerase chain reaction of the exudate was negative for herpes simplex virus types 1 and 2. A skin biopsy was performed, which revealed a polygonal cell infiltrate with slightly eosinophilic cytoplasm and reniform nuclei with positive immunophenotyping for S100, CD68, and CD1a (Figs. 2 and 3). These results, combined with the history of DI, were compatible with a diagnosis of vulvar LCH with pituitary involvement. Computed tomography scans of the thorax, abdomen, and pelvis; positron emission tomography; and bone marrow biopsy excluded other systemic involvement of the disease. The patient was treated with 0.05% betamethasone dipropionate cream and 1% ciclopirox olamine cream, with a near-complete clinical response, before starting systemic treatment. Cladribine (2-chlorodeoxyadenosine) was administered for a total of six cycles, to which