Clinical, Histological and Immunohistochemical Changes in Hypopigmented Mycosis Fungoides in Response to Narrow-Band UVB Phototherapy

Abstract

CaseA 26-year old Caucasian woman of Bulgarian descent presented at our department with multiple disseminated hypopigmented macules on the trunk and extremities since more than 4 years ( Figure 1A). The differential diagnosis included: vitiligo, pityriasis vesicolor and Mycosis fungoides-hypopigmented type. A punch biopsy was performed and histological examination revealed exocytosis of atypical lymphocytes with larger hyperchromic nuclei ( Figure 1B). A punch biopsy from normally looking skin was taken and the histological and immunohistochemical examination showed pigment incontinence and epidermotropisme of single atypical, CD3+CD4+ lymphocytes. Clinical and histological diagnosis of Mycosis fungoides-hypopigmented variant has been established.A Narrow Band Ultraviolet B-Treatment (NB-UVB) has been initiated according to the phototherapy protocol at our clinic with 4 sessions/ weekly with initial dose of 0.3 J/cm 2 and incensement of the dose with 0,05 at each session. A total number of 27 sessions have been performed and complete clinical response (disappearance of all existing lesions for at least one month) has been achieved after the 22 st session ( Figure 1C). Total UV dose was 17.5 J/ cm 2 and complete clinical response was achieved at a dose of 11.85 J/ cm 2 . No maintenance phototherapy has been administered according to the protocol.Skin biopsy after the end of the treatment taken from clinically cleared past lesion revealed fewer than initially, but still present, CD3+ T-cells, mostly CD4+, with large atypical hyperchromic nuclei in the epidermis ( Figure 1D). Exocytosis of atypical lymphocytes with larger hyperchromic nuclei were still present in fewer numbers than initially, marking a partial histological response to the therapy.The disease-free interval was 3,5 months. The patient presented with multiple hypopigmented lesions on her tights. DiscussionThe hypopigmented variant of Mycosis fungoides is rare among Caucasians and data about the efficacy and safety of NB-UVB treatment are scarce. The lower cumulative dose (17.5 J/cm 2 ) and the rapid complete response to treatment (after 22 sessions, or after a dose of 11.85 J/cm 2