[682] “Mass-Forming” Ischemic Colitis Is a Distinctive Variant with Predilection for the Proximal Colon: A Clinicopathologic Study of 16 Cases

Tze S Khor, Gregory Y Lauwers, Robert D Odze, Amitabh Srivastava. Massachusetts General Hospital, Boston, MA; Brigham and Women's Hospital, Boston, MA

Background: We have observed, anecdotally, mucosal biopsies with ischemic colitis (IC) in which the endoscopic impression is that of a mass lesion suspicious for carcinoma. The purpose of this study was to systematically evaluate the clinical and pathologic features, and outcome in patients with this unusual presentation of IC.
Design: A retrospective search was performed through the pathology archives of two participating institutions for a diagnosis of IC. Twenty patients were initially identified in whom the mucosal biopsies were reported to be from a colonic mass but the pathologic findings were those of an IC. Four of these cases were excluded because review of colonoscopic findings showed prolapse (n=1), polyp (n=2) and diverticular disease (n=1) without any concern for malignancy. The remaining 16 patients formed the final study group. Pathologic findings (biopsy=16 cases; resection =4 cases) were reviewed in all cases. Demographic, clinical, radiologic and follow-up data was obtained by medical chart review.
Results: The study group consisted of 5 males and 11 females with a mean age of 74.5yr (range 47-98 yr). Patients presented most often with abdominal pain (56.3%), either alone or associated with hematochezia (25%) or diarrhea (12.5%). CT scan was done in 8 patients and 6/8 showed segmental thickening suspicious for a neoplasm. Colonoscopic findings included an exophytic mass (n=13), circumferential firm constriction (n=2), or diffuse wall thickening with ulceration (n=1). The “mass lesions” were 1-8cm in size (mean: 4.7cm) and were located in the cecum (n=6), ascending colon (n=3), hepatic flexure (n=1), transverse colon (n=2), descending colon (n=2) and sigmoid colon (n=2).
Mucosal biopsies in all 16 patients showed typical features of IC. 4/16 patients underwent segmental colectomy. The mass-like appearance in all 4 resections was due to marked submucosal edema. Follow-up was available in 14/16 patients and ranged from 1-150 mth (mean: 35.5 mth). No malignancy was identified on resection or follow-up in any case. 3 patients had follow-up colonoscopy 1-3 months after initial diagnosis and showed complete resolution of the mass lesion.
Conclusions: IC may rarely mimic a mass lesion worrisome for malignancy on colonoscopic examination. This “mass-forming” variant of IC shows a female predominance and a predilection for the proximal colon. Awareness of this phenomenon may prevent unnecessary resections in these patients.
Category: Gastrointestinal

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 105, Monday Morning


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