[A Case of Intravascular Lymphoma Mimicking Acute Sinusitis in Which the Outcome was Unfortunate].

Intravascular large B-cell lymphomas (IVLBCL) are a rare and aggressive non-Hodgkin Lymphoma characterized by proliferation of malignant lymphoid cells into the small blood vessels of the whole body. Making a diagnosis is very difficult due to the lack of mass formation and lymph node enlargement, resulting in a poor prognosis. We report herein on a case of IVLBCL which was proved by a biopsy of the nasal mucosa during endoscopic sinus surgery.