Hypopigmented mycosis fungoides

Clinical features

•Associated with a good prognosis

•More commonly seen in children & adolescents although any age can be affected

•M=F

•Predilection for African & Asian descent; much less often in Caucasians

•Generally asymptomatic, scaly, hypopigmented patches on trunk, buttocks & extremities

•Clinically mistaken for vitiligo, post inflammatory hypopigmentation, tinea versicolor & pityriasis alba

Histological features

•Indistinguishable from classical mycosis fungoides with the additional feature of marked pigmentary incontinence

•CD8+ve cells may predominate

•Hypopigmentation likely associated with melanocytic toxicity & reduced melanocyte population although this isn’t always a feature

•Masson-Fontana may show reduced melanin with SOX10 & with Melan-A showing reduced numbers of melanocytes

Childhood and adolescent mycosis fungoides

•Exceedingly rare

•Lesions are frequently hypopigmented

•Presents with patch & plaque stage disease

•Prognosis is generally good

•Histology is identical to classical mycosis fungoides

•A CD8 immunophenotype is common particularly in hypopigmented variants