Intravascular large B-cell lymphoma (IVLL) is a rare subtype of extranodal diffuse large Bcell lymphoma and is very difficult to diagnose in patients antemortem due to nonspecific presentation of the disease. We report a case of IVLL in a 68-year-old white female who presented with 3-month history of fever of unknown origin (FUO), night sweat, and weight loss. Laboratory tests revealed bilateral adrenal enlargement and adrenal insufficiency. IVLL was diagnosed only at autopsy. A review of the English language medical literature indicates that it is not uncommon for IVLL presented initially with FUO, bilateral adrenal enlargement, and adrenal insufficiency. We present this case to call for heightened awareness of the possibility of IVLL, particularly in an elderly woman who presents with FUO, bilateral adrenal enlargement, and adrenal insufficiency. The pathophysiologic mechanisms of adrenal insufficiency in IVLL are also discussed. Am. J. Hematol. 81:411-413, 2006. V V C 2006 Wiley-Liss, Inc.