Introduction: Specific involvement of the mucous membranes is possible during the course of mycosis fungoides but has seldom been reported, except in postmortem series. A single mucous membrane is most often involved, mainly in the mouth. Such mucous lesions are generally ominous with regard to the general outcome of the disease.
Observation: A 74 year-old woman was investigated for mycosis fungoides complicated with lesions around the mouth and of the mucosa, involving the tongue and esophagus, featuring ulcerated nodules with specific chorion infiltration and epidermotropism. This progression was rapidly followed by a fatal outcome, in spite of various systemic treatments.
Discussion: This case report of mycosis fungoides displaying multiple and predominant oral and mucosal involvement of mycosis fungoides is unique. The rapidly unfavorable outcome confirms the ominous prognosis of mucous lesions, whereas no patent visceral extension was detected. The mechanisms underlying the mucous membranes involvement is discussed.