Lethal midline granuloma: a case of Ki-1 lymphoma.

Lethal midline granuloma syndrome (LMG) is the clinical term generally used to describe a rare clinical entity of unknown cause characterized by a progressive and often fatal ulceration and destruction of the upper airway involving the nose, the paranasal sinuses and the soft tissues of the face. The following histopathologic entities have always been grouped under the term LMG: Wegener granulomatosis (WG), non-Hodgkin lymphoma, polymorphic reticulosis (PR) and idiopathic midline destructive disease (IMDD). Today in order to begin an adequate therapy a differential diagnosis is necessary. The progresses in clinical immunology and immunohistochemistry and cytophotometric findings are useful to define the LMG syndrome better. First of all the LMG must be discriminated from localized WG occurring in the midface. Serologic examinations of patients with WG in its active form show a high percentage of autoantibodies against cytoplasmic structures in leucocytes and monocytes. Moreover a review of the literature allows us to suppose that cases described as IMDD and PR are indeed a large evolutionary spectrum from almost benign to fatal malignant lymphoma. We report a case of Ki 1-lymphoma presenting as LMG syndrome.