Idiopathic myointimal hyperplasia of mesenteric veins mimicking steroid-refractory ulcerative colitis: A case report

Table 1 Differential diagnosis of idiopathic myointimal hyperplasia of mesenteric veins and other causes of inflammatory colitis

Disease	Clinical features	Endoscopic findings	Histopathology	Distinguishing features
IMHMV	Chronic bloody diarrhea, left-sided predominance, steroid-refractory	Segmental erythema, deep ulcers, edema	Myointimal hyperplasia of mesenteric veins with preserved arteries	Diagnosis usually requires surgical specimen
Ulcerative colitis	Chronic relapsing bloody diarrhea	Continuous inflammation from rectum	Chronic active colitis, crypt distortion	Responds to immunosuppressive therapy
CMV colitis	Immunocompromised host	Large punched-out ulcers	CMV inclusion bodies	CMV IHC/PCR positive
MMF-induced colitis	MMF exposure	Variable erythema/ulcers	Increased epithelial apoptosis	Improves after MMF withdrawal
Infectious colitis	Acute onset, fever	Diffuse erythema, exudate	Acute neutrophilic inflammation	Positive stool studies
Ischemic colitis	Acute abdominal pain	Segmental ischemic ulceration	Ischemic injury	Typical vascular risk factors
Enterocolic lymphocytic phlebitis	Abdominal pain and diarrhea; may mimic IBD or ischemic colitis	Segmental or diffuse inflammatory/ischemic changes	Lymphocytic inflammation selectively involving veins and venules, with arterial sparing	True venous phlebitis with lymphocytic infiltration, unlike non-inflammatory myointimal hyperplasia in IMHMV

IMHMV: Idiopathic myointimal hyperplasia of mesenteric veins; CMV: Cytomegalovirus; IHC: Immunohistochemistry; PCR: Polymerase chain reaction; MMF: Mycophenolate mofetil; IBD: Inflammatory bowel disease.