Invisible mycosis fungoides: a diagnostic challenge.

We describe a 76-year-old woman who had persistent generalized pruritus as the only cutaneous manifestation of a cutaneous T-cell lymphoma (mycosis fungoides). No cutaneous lesions were observed throughout the patient's course. Skin biopsy specimens obtained from normal-looking pruritic skin revealed a discrete perivascular lymphocytic infiltrate in the upper dermis and focal intraepidermal clusters of atypical lymphoid cells (Pautrier's microabscesses). PCR analysis of TCR-gamma gene disclosed a monoclonal T-cell rearrangement. Sequencing of the PCR monoclonal product identified the J(8)V(2)C(2) TCR gene rearrangement. This observation illustrates the existence of a peculiar and exceedingly rare form of mycosis fungoides characterized only by persistent pruritus unresponsive to several therapeutic approaches. The diagnostic difficulties of this rare variant are stressed.