Cutaneous T-cell lymphoid dyscrasia: a unifying term for idiopathic chronic dermatoses with persistent T-cell clones.

It often takes several years before the diagnosis of mycosis fungoides is clearly established. During this period preceding the diagnosis of cutaneous T-cell lymphoma (CTCL), some patients experience a variety of distinct skin conditions of ambiguous origin. With refinement in the methods of T-cell clonal detection in skin biopsy specimens, we can now establish that many of these preceding entities are characterized by a T-cell clone. Therefore, we studied the association of these clonal conditions with CTCL. We identified 8 distinct clinicopathological conditions characterized by the frequent detection of T-cell clonality, a chronic course often recalcitrant to topical therapy, lack of a known triggering event, and lack of morphologic evidence of a T-cell lymphoma with potential for progression to CTCL. We propose the term cutaneous T-cell lymphoid dyscrasias to unify these entities. Defining the preceding stages of CTCL is important to properly categorize these conditions and to help us understand and redefine the evolution of idiopathic clonal dermatoses and their potential for lymphoma progression.