Practical Aspects Regarding the Histopathological Diagnosis of Early Mycosis Fungoides

Mycosis fungoides is the most common primary T-cell lymphoma of skin. The disease has a protean clinical and histological presentation in its early patch and plaque stages, when distinction from mimicking inflammatory dermatoses is difficult. Since no single criterion is specific enough, a reliable diagnosis in early stages requires integration of clinical, histopathological and molecular findings. In skin biopsies, the most helpful histologic features are the detection of atypical lymphocytes in the epidermis with minimal epidermal changes, basal alignment of lymphocytes along dermal-epidermal junction and formation of Pautrier microabscesses. An aberrant immunophenotype of T cells and molecular detection of a clonal T-cell population are factors that could allow a more specific diagnosis. This work recapitulates and discusses these features from a practical perspective.