Folliculotropic mycosis fungoides treated with topical corticosteroids: A case report and a review of its trichoscopic features

Sir, Folliculotropic mycosis fungoides (FMF) represents 5% of cutaneous lymphomas. It is a rare variant of mycosis fungoides that differs not only by its clinical and histological presentation but also by its prognosis. It is characterized by an infiltrate of atypical lymphocytes in the perifollicular dermis and hair follicles, with or without mucinosis, while epidermotropism may be completely absent. Dermoscopic and trichoscopic features in FMF are variable and not well defined. Herein, we present a unique case of FMF in a female patient with scalp alopecia, which evolved well under topical treatment. We review its trichoscopic findings. A 64-year-old female presented to our dermatology department with a seven-month history of an alopecic plaque on the scalp. No complaints of itching or burning were made. There was a history of arterial hypertension and dyslipidemia, which has been treated by oral medication. A physical examination revealed an erythematous, non-infiltrated, circumscribed alopecia in the frontal region of the scalp 8 cm in size associated with alopecia of the eyebrows (Fig. 1a and 1b). No other cutaneous lesions were evident. There were no other alopecic or infiltrated plaques, no hyperkeratosis or follicular papules, no acneiform lesions. A histopathological examination of a biopsy specimen revealed an epidermis covered with focally parakeratotic hyperkeratosis. The dermis contained a lymphocytic infiltrate in the follicles and the perifollicular areas. The hair follicles were dissociated by Alcian blue-positive edema. Folliculotropic infiltrate showed positive staining for CD3 and CD4. Some lymphocytes were CD20+ (Fig. 3a – 3c). The clinical, histological, and immunohistochemical appearance was consistent with the diagnosis of folliculotropic MF. Further examination showed no extracutaneous involvement. A full blood count and liver and kidney parameters were found to be in the normal range. A thoraco-abdomino-pelvic CT scan was without abnormality. Referring to the WHO/EORTC classification, the patient’s disease was stage IA. We initiated treatment with a high-potency topical corticosteroid with close monitoring. After two months of treatment, improvement was observed (Fig. 1c). No other cutaneous lesions were evident. There were no other alopecic or infiltrated plaques, no hyperkeratosis or follicular papules, no acneiform lesions. A histopathological examination of a biopsy specimen revealed an epidermis covered with focally parakeratotic hyperkeratosis. The dermis contained a lymphocytic infiltrate in the follicles and the perifollicular areas. The hair follicles were dissociated by Alcian blue-positive edema. Folliculotropic infiltrate showed positive staining for CD3 and CD4. Some lymphocytes were CD20+ (Fig. 3a – 3c). The clinical, histological, and immunohistochemical appearance was consistent with the diagnosis of folliculotropic MF. Further examination showed no extracutaneous involvement. A full blood count and liver and kidney parameters were found to be in the normal range. A thoraco-abdomino-pelvic CT scan was without abnormality. Referring to the WHO/EORTC classification, the patient’s disease was stage IA. We initiated treatment with a high-potency topical corticosteroid with close monitoring. After two months of treatment, improvement was observed (Fig. 1c).