Langerhans cell histiocytosis of the vulvaTo the Editor: Langerhans cell histiocytosis (LCH) is regarded as a functional disorder of immune regulation that results in the proliferation of itnmature Langerhans cells [l]. The disorder may be localized or disseminated with multisystemic disease. The oral cavity is frequently affected, but the involvement of the female genital tract is very uncommon [l]. We describe two patients who had LCH of the genital tract.Case 7. A 38 year-old woman, in previously good health, presented in 1987 a bilateral pneumothorax.The chest X-ray demonstrated a honeycombed reticulonodular pattern, and a lung biopsy was compatible with pulmonary histiocytosis X. One year later, she developed poiyuria and polydipsia and the diagnosis of diabetes insipidus was made. In 1989, two osteolytic lesions were detected by bone X-ray in the palate and the mandible, respectively. Six months later, she noticed the appearance of ptiiritic ulcerative lesions on the right axilla and vulva. Cutaneous physical examination revealed two indurated ulcers with undermined borders, 1 cm in size, localized on the right labium minora of the vulva and the right axilla. Histological, ultrastructural and immunohistochemical ( Fig. 1) examination of biopsies taken frotn these lesions confirmed the diagnosis of LCH.Case 2. A 42 year-old woman had a six months history of pruritic, erosive and ulcerating lesions on the vulva. There was no significant past medical history. Physical examination revealed several small erosions over an erythematous area on the left labium minora. She was first treated with topical acyclovir and topical antibiotics without relief. The histological examination showed a dermal infiltrate containing abundant Langerhans-type histiocytes. Ultrastructural studies revealed the presence of Birbeck granules in the cytoplasm of these cells (Fig. 2). Extensive studies, including haematologic profile, serum and urine biochemistries, thyroid hormones and bone x-ray, were strictly normal and gave no evidence of multisystemic involvement. The lesions were treated with surgery, but a short time afterward she had a local recurrence. Three years later, she has developed poiyuria and polydipsia, and the diagnosis of diabetes insipidus has been made.