May-I-Ro syndrome (Melkersson-Rosenthal syndrome is named for the earliest reports by Melkersson (1928) in Switzerland and Rosenthal (1931) in Germany. It is clinically characterized by recurrent orofacial swelling, recurrent facial paralysis, and cleft tongue triad. Granulomatous labyrinthitis is one of its manifestations.
[Etiology] The etiology is unknown. The disease may have genetic factors, infectious factors, allergic factors, and vasodilatory dysregulation. Predisposing factors such as odontogenic infectious lesions are sometimes found clinically, and there are also reports in the literature that the organism is associated with allergy to cinnamaldehyde, alcohol, cobalt, cocoa, monosodium glutamate, and cinnamon. It has also been suggested that it is a variant of nodular disease (sarcoidosis-like).
[Pathology] Except for the pathological manifestations of granulomatous labyrinthitis seen in lip specimens, no pathological basis could be found for any other characteristic clinical signs. Tissue specimens from the swollen area of the lip had typical epithelioid cell granuloma manifestations. Nodules and Langerhans cells formed by epithelioid cells in chronic granulomatous inflammatory tissue, and interstitial edema and vasculitis can be seen.
Clinical manifestations】Recurrent orofacial swelling, recurrent peripheral facial palsy, and split tongue triad of May-Ro syndrome may occur simultaneously or sequentially over several months to years.