Invasive carcinoma is not absent i...

Invasive carcinoma is not absent in 30 to 40 percent of rectal villous adenomas. Approximately 10 percent of biopsynegative villous adenomas contain invasive cancer, equal if those with induration, ulceration, and other signs of malignancy are exclud If a potentially malignant adenoma is misdiagnosed as a benign lesion, a suboptimal resection may be performed for a potentially curable lesion. Several small studies have reported that endorectal ultrasound (ERUS) examination can identify focal carcinomas that are missed through biopsy of adenomas. The generalizability of these studies is limited at number and selection of participants and by dint of the variability in the utility of ERUS, depending upon the operator. Worrell and colleagues reviewed published studies since 1986 to assess the potential part of ERUS in improving diagnostic accuracy for patients with biopsy-negative rectal adenomas.

Their initial search of an electronic database identified 47 articles, moreover only five studies required perfect excision of the lesion and comparison of the ERUS and histopathologic diagnosis. Histopathologic examination of the excised lesions identified focal invasive carcinoma in 62 (24 percent) of the 258 biopsy-negative specimens. Fifty (81 percent) of these lesions were diagnosed correctly by way of ERUS examination before exci-sion. reciprocally ERUS incorrectly identified 12 percent of benign rectal adenomas as malignant. The authors estimate that these originates are equivalent to requiring five patients with biopsy-negative adenomas to be examined by way of ERUS to prevent missing common case of invasive carcinoma. reciprocally one case would be incorrectly diagnosed for each 11 patients examined with ERUS.

The authors close that use of ERUS and directed biopsy of rectal adenomas could remodel the rate of misdiagnosis of malignant lesions from 24 percent to 5 percent They make acceptable the routine use of adjunctive ERUS in the evaluation of all rectal villous adenomas, especially those with increased clinical suspicion of malignancy.

Worrell s et al. Endorectal ultrasound detection of focal carcinoma within rectal adenomas. Am J Surg May 2004;187:625-9

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