At the Root: Cutaneous Langerhans Cell Histiocytosis
The present case has been reported in the in the American Journal of Medicine. Hair loss is of deep concern to patients, mainly because of its effect on appearance. On rare occasions, however, areas of balding can signal malignancy.

A 33-year-old woman was referred to a dermatology clinic because of a 15-year history of scalp eruption accompanied by intense itching and progressive hair loss. Previously, she was diagnosed with seborrheic dermatitis associated with female androgenic alopecia. She was treated with topical steroids for numerous years without improvement, except for transient relief of itching.

Physical examination revealed moderate hair thinning of the frontoparietal scalp, a finding in line with the diagnosis of female androgenic alopecia. Numerous follicular-based, erythematous, scaling papules with overlying yellow to brown crusts were noted on the parietotemporal and vertex areas of the patient's scalp, where hair thinning was striking.

The interfollicular skin appeared atrophic, as a result of the prolonged steroid applications, but was without erythema or scaling. Areas of scarring alopecia were absent. The diagnosis of seborrheic dermatitis was questioned because the condition manifests with erythema and desquamation of the scalp and involves both perifollicular and interfollicular skin.

At the same time, the patient's hair loss in the parietotemporal and vertex regions could not be explained by her previous diagnosis of androgenic alopecia, which commonly spares those areas in females.

Thus, a 4-mm punch biopsy was taken from a papular lesion. Histopathology revealed dermoepidermal detachment and a dermal infiltrate composed of what appeared to be Langerhans cells, clusters and sheets of large ovoid cells with abundant eosinophilic cytoplasm, and a reniform nucleus.

This accumulation of cells tended to have a periadnexal distribution, leading to follicular atrophy, and the accumulation of cells was mixed with numerous lymphocytes, plasma cells, neutrophils, and eosinophils.

Based on the combined clinical, histologic, and molecular findings, a diagnosis of Langerhans cell histiocytosis was made. To stage the disease, a total-body computed tomography scan and positron emission tomography were performed. No internal organ involvement was seen.

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