P2531 - Preoperative Diagnosis of Idiopathic Myointimal Hyperplasia of the Mesenteric Veins (IMHMV) in a Post–Liver Transplant Patient

Ryan F. Hughes, MD¹, Danielle Morelli, MD², Eliza Cricco-Lizza, MD¹, Jose Jessurun, MD¹, David Wan, MD², Carl V. Crawford, MD¹
1NewYork-Presbyterian / Weill Cornell Medical Center, New York, NY; 2NewYork-Presbyterian Hospital/Weill Cornell Medical Center, New York, NY

Introduction:

Idiopathic myointimal hyperplasia of the mesenteric veins (IMHMV) is an exceedingly rare non-thrombotic, non-inflammatory cause of ischemic colitis, characterized by luminal obliteration of medium to large-sized mesenteric veins by proliferating smooth muscle cells and myofibroblasts embedded in a myxoid matrix, that is often clinically misdiagnosed as inflammatory bowel disease (IBD) or infectious colitis. It is typically diagnosed following surgical resection via full-thickness histology, and as a result is often a delayed diagnosis, generally preceded by prolonged hospitalization and failed medical therapies. This case represents a rare instance in which the histologic diagnosis of IMHMV was made preoperatively.

Case Description/

Methods: A 41-year-old woman with alcohol-associated cirrhosis status-post deceased donor liver transplant 1.5 years ago presented with worsening diffuse abdominal pain, non-bloody diarrhea, anorexia, and nausea for 2 months. Labs revealed hemoglobin 8 (baseline 14) g/dL, C-reactive protein 12 mg/L, Clostridioides difficile PCR (+)/toxin assay (-). Serial cross-sectional imaging showed progressive left-sided colitis with proximal distension. The patient underwent five total lower endoscopies, notable for severe sigmoidal inflammation/focal stricture with transverse colon and rectal sparing. She received extended antibiotic therapy against C. difficile as well as two fecal microbiota transplantations without clinical improvement. The third lower endoscopy yielded adequate tissue sample for histologic examination revealing ischemic changes with pseudomembranes, remodeling of lamina propria capillaries with arteriolarization, circumferential subendothelial fibrin deposits, and intravascular thrombi consistent with venous hypertension secondary to IMHMV. Bacterial peritonitis (secondary to a contained colonic perforation) was diagnosed on hospital day 29 and treated uneventfully with piperacillin-tazobactam. On hospital day 44, the patient underwent hemicolectomy with examination of the resected specimen confirming the diagnosis of IMHMV. The patient clinically improved without complication and was discharged on hospital day 53.

Discussion:

IMHMV may be confounded by or mistaken for infections like C. difficile and may clinically mimic IBD. Surgical resection is curative, however delays to surgery of up to 6 months or longer have been reported. Early preoperative diagnosis of IMHMV may reduce unnecessary therapies and decrease time to surgery as definitive treatment.


Figure: Figure 1: Endoscopically-obtained sigmoid colon biopsies revealing histologic changes consistent with IMHMV– A. Intravascular fibrin thrombi; B. Fibrinopurulent exudate; C. Subendothelial fibrin deposits (black arrows) with fibrin thrombi (green arrow); D. Vascular remodeling (arteriolarization).


Figure: Figure 2. A. Sigmoid colon with severe congestion, erythema, ischemia, and pseudomembrane formation. B. Sigmoid stricture at 30 cm. C. Resected left colon specimen with notable mucosal thickening, erythema, ulcerations, pseudomembranes, and pericolic fat wrapping. D. Surgical specimen revealing myointimal hyperplasia of mesenteric vein; E. Surgical specimen revealing normal veins for comparison in an unaffected region.

Disclosures:
Ryan Hughes indicated no relevant financial relationships.
Danielle Morelli indicated no relevant financial relationships.
Eliza Cricco-Lizza indicated no relevant financial relationships.
Jose Jessurun indicated no relevant financial relationships.
David Wan: Medtronic – Data Monitoring Committee.
Carl Crawford: Ferring – Advisor or Review Panel Member, Consultant, Grant/Research Support, Speakers Bureau. lumen – Grant/Research Support. nestle – Advisory Committee/Board Member, Consultant, Grant/Research Support, Speakers Bureau. Phathom – Speakers Bureau. vedanta – Grant/Research Support.

Ryan F. Hughes, MD¹, Danielle Morelli, MD², Eliza Cricco-Lizza, MD¹, Jose Jessurun, MD¹, David Wan, MD², Carl V. Crawford, MD¹. P2531 - Preoperative Diagnosis of Idiopathic Myointimal Hyperplasia of the Mesenteric Veins (IMHMV) in a Post–Liver Transplant Patient, ACG 2025 Annual Scientific Meeting Abstracts. Phoenix, AZ: American College of Gastroenterology.