Persistent lymphoedema in Morbihan disease: formation of perilymphatic epithelioid cell granulomas as a possible pathogenesis

Morbihan disease is a rare complication of rosacea, characterized by persistent lymphoedema on the upper half of the face, occurring during the chronic clinical course of rosacea. This refractory condition has been also designated as 'rosacea lymphoedema' and 'solid persistent facial oedema of rosacea'. We report a patient with Morbihan disease showing persistent lymphoedema on the upper half of the face accompanied by unique histological findings of striking dermal dilated lymphatics and damage of the lymphatics at the site of the adjacent epithelioid cell granulomas, with histiocytes bulging into the lymphatic lumen. The marked epithelioid cell granulomas forming around dermal lymphatic vessels with subsequent lymphatic damage and luminal obstruction by histiocytic infiltration may account for the development of lymphoedema in this patient.