Cecal Bascule: A Rare Adverse Event as a Result of Retuximab Therapy

Abstract

Introduction: Cecal volvuli (CeV) are relatively rare, accounting for 10% of all cases of colonic volvuli. Three types of cecal volvuli (CeV) exist: 80% are type I and II, developing from clockwise and counterclockwise axial torsions, respectively, of the cecum (Ce) around its mesentery. A rare type III or Ce bascule (CeB) involves upward folding of the Ce. All three types are dependent on previous existence of abnormally mobile Ce (congenital or acquired). In CeB, folding of the Ce anterior to the ascending colon (AC) causes inflammatory adhesions, fixing the anterior surface of the Ce to the mid-AC. This fixation leads to increased tension on the bowel wall, resulting in gangrene with subsequent perforation. Rituximab (RTX) is a chimeric human/mouse monoclonal Ab that binds to a CD20 Ag present on the surface of B lymphocytes, thereby causing lysis of tumor cells. A pooled analysis of clinical trials in patients with CD20-positive non-Hodgkins lymphoma (NHL) has indicated a higher incidence of GI perforations in the RTX plus chemotherapy (CTX) arm, as compared to CTX only arm. Although the mechanism is unclear, aggressive tumor lysis response may be related to the high CD20 expression on tumor cells, leading to perforations in patients with lymphomatous involvement of the GI tract. Ceb as a consequence of RTX therapy, although plausible through the same mechanism, has thus far not been described. Case: A 65-year-old male with NHL treated with RTX presented in acute distress with rigid, distended and severely tender abdomen with hypoactive bowel sounds. A plain film revealed dilated sb with no obvious free air. CT abd/pelvis with PO/IV contrasts showed a markedly dilated Ce with no evidence of BO, volvulus or bowel wall thickening, moderate distention of AC and transverse colon with stool and decompressed descending colon, and rectum with no dilation of SB. Repeat CT with water soluble contrast through the rectal tube showed anteromedial displacement of extensively fecalized and markedly dilated Ce in relation to AC, resulting in CeB and possible Ce obstruction. Ultimately, the patient's symptoms resolved with conservative management, and he was discharged in stable condition. Conclusion: We present the first case of a CeB-associated with RTX therapy. Clinicians should maintain a high degree of vigilance in patients undergoing treatment with RTX who present with non-specific abdominal symptoms.Figure