Monoclonal rearrangement of the T cell receptor gamma-chain in lichenoid pigmented purpuric dermatitis of gougerot-blum responding to topical corticosteroid therapy.

Lichenoid pigmented purpuric dermatitis of Gougerot-Blum belongs to a group of closely related disorders which are termed pigmented purpuric dermatoses. It clinically manifests itself with grouped lichenoid papules in association with purpuric lesions. We report a case of lichenoid pigmented purpuric dermatitis of Gougerot-Blum with a heavy band-like CD4-positive lymphocytic infiltrate and clonal rearrangements of the gamma-chain of the T cell receptors as detected by polymerase chain reaction/denaturing gradient gel electrophoresis. Monoclonal expansion of T cells in combination with certain histological features of mycosis fungoides (MF) might support a biological relationship between lichenoid pigmented purpuric dermatitis of Gougerot-Blum and MF. However, prompt clinical response to topical steroid therapy supports the benign clinical nature of our case.