A Case of Adult Generalized Cutaneous Langerhans Cell Histiocytosis.

Dear Editor:Langerhans cell histiocytosis (LCH) is a rare disease and generally affects infants and children. Adult-onset form and generalized cutaneous lesions at presentation without extracutaneous involvement are uncommon. We report an unusual case of generalized adult cutaneous LCH without extracutaneous involvement.The patient was an 81-year-old man who complained of rapidly growing eruptions on the perianal area, groins, axillae, face, and ankles. He stated that the lesions had been present for about 3 months—they first appeared on the perianal area, and then extended rapidly to the groins, axillae, face, and ankles. Physical examination revealed disseminated violaceous papules and plaques on the perianal area, groins, axillae, face, and ankles; the lesions on the perianal area and groins were confluent and ulcerated (Fig. 1). He had no weight loss and no palpable lymphadenopathy or organomegaly. The laboratory results, including complete blood count with differential, liver, and renal function tests, were within the normal range. Bone marrow biopsy examination revealed no evidence of tumor involvement. In addition, a whole body positron emission tomography/computed tomography study showed no involvement of any organ. Histopathologic findings of the lesions showed diffused infiltration of large tumor cells in the dermis, and epidermotropism was appreciated. The tumor cells had a moderate amount of eosinophilic cytoplasm and grooved nuclei consistent with Langerhans cells. These cells were mixed with small lymphocytes, neutrophils, and eosinophils (Fig. 1). The immunohistochemistry staining showed that the tumor cells were diffusely positive for S-100, CD1a, langerin, leukocyte common antigen (LCA), CD4, and CD68, but negative for CD3, CD5, CD20, CD34, CD79a, human melanoma black (HMB)-45, and melan-A (Fig. 2). The Ki-67 proliferating index was approximately 60%. Taken together, these morphological and immunological data were consistent with a cutaneous LCH according to the World Health Organization diagnostic criteria.Fig. 1(A~C) Multiple, erythematous, rust-colored papules and plaques with erosions distributed on the perianal area, groins, and axillae; (D~F) multiple, erythematous macules and papules on the face and ankle.Fig. 2(A) Under low-power microscopic examination, the lesion shows diffused infiltration of tumor cells in the dermis (Hu0026E, ×25). (B) The lesion shows infiltration of large tumor cells in the dermis, and epidermotropism was appreciated (Hu0026E, ...After diagnosis of LCH, the patient was referred to an oncologist and received chemotherapy. However, the patient died of myocardial infarction 10 days after being diagnosed with the disease.LCH is a clonal proliferative disorder of Langerhans cells, typically seen in infants and children. Occurrences of LCH in the adult population are rare, but even rarer with the disease limited to the skin1. Compared with LCH in infants and children, adult LCH occurs predominantly in bone and presents mainly as single system disease, with a more chronic clinical course and a better prognosis. The clinical presentation of cutaneous LCH in adults is variable. It can present as papules, plaques, or nodules localized to a single anatomic site or in a generalized distribution. Pruritic papules or nodules of cutaneous LCH may appear similar to prurigo nodularis, and other (non-LCH) papules or ulcers of the external genitalia1,2. Sites most frequently involved include the scalp, trunk, flexural and intertriginous areas, glabrous skin, and external genitalia1. Treatment of cutaneous LCH is controversial. Several therapeutic approaches have been reported in the literature, according to the extent of disease: topical and systemic corticosteroids, topical imiquimod, psoralen plus ultraviolet A (PUVA), thalidomide, interferon-α, vinblastine, and surgery have been used for treating this disease3,4,5.