Buried Adenocarcinoma Masquerading as a Refractory Rectal Stricture

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45 year old African American female with a long standing history of Crohn's colitis (involving the descending and sigmoid colon with perianal fistulas) and medication non-compliance presented with worsening constipation for months. Patient was not on medications at the time of presentation, but has a history of treatment with asacol, azathioprine and infliximab. Patient denied fevers, nausea, vomiting or rectal bleeding. Colonoscopy revealed a 5 cm long tight rectal stricture about 10 cm from the anal verge along with extensive pan colitis and normal small bowel. Biopsy of the stricture revealed inflammatory infiltrate. MR enterogram revealed a tight rectal stricture with enhancement indicating inflammation. Patient was treated with high doses of prednisone followed by infliximab infusions along with endoscopic dilations to which she had minimal response. This was followed by injection to infliximab directly into the rectal stricture with limited response. Patient was referred for surgery where she underwent abdominal perineal resection of rectum with end-colostomy. The stricture appeared benign on macroscopic examination but pathology reports revealed intra-strictural adenocarcinoma and normal overlying mucosa. She had to undergo repeat surgery for complete resection followed by radiation and chemotherapy. Discussion: The association between inflammatory bowel disease (IBD) and colorectal cancer (CRC) is well-known and has been widely described in literature. The risk of malgnancy is directly related to the severity of perianal involvement, extent of disease and its time course. In CD the risk is estimated to be around 30% after 25 years of diagnosis and noted to be higher in patients who receive the diagnosis before the age of 30. Our patient had long standing crohn's colitis, which was uncontrolled due to medication non-compliance. In addition, she was a smoker which increases the risk of malignancy. The stricture was biopsied multiple times on endoscopy and imaged with MR enterogram, which failed to reveal malignancy. Even during surgery, the surgeon did not suspect malignancy on gross examination as the mucosa appeared normal. The pathology specimen (see figure) demonstrates buried glands with adenocarcinoma interspersed within the stricture. Overlying mucosa appears normal. This is the first report where we describe a case of adenocarcinoma buried within the stricture with normal overlying mucosa. It is important for clinicians to have a high suspicion of malignancy in strictures which fail to respond to intensive therapy.Figure 1Figure 2Figure 3