A 43-year-old woman with systemic lupus erythematosus (SLE) was treated for lupus pleurisy. During the course of her illness, she abruptly suffered severe right hypochondriac pain and high-grade fever. Abdominal ultrasonography revealed a thickening of the gallbladder wall without cholelithiasis, and she was diagnosed with acute acalculous cholecystitis (AAC). Laparoscopic cholecystostomy was performed. Pathological examination revealed lymphocytic venulitis without arteritis. Antiphospholipid antibodies were not demonstrated during the course of illness. From these findings, the cause of AAC was revealed as a mesenteric inflammatory veno-occlusive disease (MIVOD), which is a novel venopathy mainly affecting the mesenteric vein and/or its branches, causing serious ischemic complications. MIVOD should be considered as a possible cause of AAC.