[Cutaneous T-cell lymphoma, cutaneous hyperpigmentation and paraneoplastic pemphigus]

Paraneoplastic pemphigus is an autoimmune mucocutaneous disease usually associated with neoplasia as lymphoid proliferations. We report the original case of a patient who had developed a mycosis fongoide preceded by a paraneoplastic pemphigus. To our knowledge, this association has never been reported before. Cutaneous manifestations of mycosis fongoide as pigmentary change are known. This mycosis fongoide was particular in its progressive cutaneous hyperpigmentation.

A 70-year-old male patient developed a mycosis fongoide with CD30 positive cells in the dermis several months after the diagnosis of a paraneoplastic pemphigus. Simultaneously, a cutaneous hyperpigmentation was predominantly noticed on photo-exposed areas, which improved after chemotherapy.

Paraneoplastic pemphigus may precede the cancer, as is shown by our present case. This paraneoplastic pemphigus is singular because of the lack of oral erosions, patient's prolonged survival and its association with a mycosis fongoide. The diagnosis of mycosis fongoide with CD30 + cells was finally established together with its relationship to the cutaneous hyperpigmentation. Indeed, a few cases of pigmentary changes in mycosis fongoide have already been reported. The pathogenesis is still unknown, but the role of mast cell and stem cell factor in hyperpigmented mycosis fongoide has been proposed.