30. Hypopigmented CD8+ patch stage mycosis fungoides in an adolescent patient

Abstract

Mycosis fungoides (MF) represents the most common form of cutaneous T cell lymphoma. The majority of cases represent a neoplastic proliferation of CD4+/CD8– T cells occurring in middle aged and older adults, often with initial presentation as long standing erythematous patches on non-sun exposed skin. There is, however, a wide range of clinical, morphological and immunophenotypic variation in the presentation of MF. Hypopig-mented MF (HyMF) is an uncommon clinical variant which appears to have a predilection for young patients with dark skin, and often shows a CD4–/CD8+ immunophenotype. These characteristics present significant challenges for the pathologist in terms of recognising the possibility of a form of MF and separation from inflammatory dermatoses, particularly the early ‘inflammatory’ phase of vitiligo. Additionally, when the proliferation is recognised as neoplastic, separation from aggressive forms of CD8+ T cell lymphoma is critical. We present a case of HyMF in a 16-year-old male showing the CD4–/CD8+ immunophenotype and discuss the differential diagnosis of and clinicopathological approach to these challenging cases.