Purpose: About 10 % of biopsy-negative villous adenomas harbour invasive carcinoma. Transrectal ultrasound (TRUS) -guided biopsy is routinely being performed in the diagnosis of recurrent rectal cancer and used in the diagnosis of prostate cancer. However, to the best of our knowledge, we are not aware of any reports in which a TRUS-guided biopsy of primary rectal tumours has been used. We recently performed this new method of TRUS - guided biopsy of a primary rectal tumour.
Results: Because three set of clinical examination-based biopies of a primary rectal tumour were negative, a TRUS – guided biopsy was attempted. The tumour was situated 9 cm above the anal verge and was staged based on CT, MRI and TRUS. All methods of assessment showed a T4,N0,M0 rectal tumour. A forward "looking" 6.5 MHz transrectal transducer was used. Two passes with a histologic 1,2 mm Gallini needle biopsy of a suspicious hypoechoic area within the tumour was carried out. The biopsy guide system permitted us to maintain the transducer in position and repeat the needle pass without to reintroducing the transducer into the rectum. Both biopsies were consistent with adenocarcinoma. No pain or other complications of the procedure were encountered.
Conclusion: TRUS has the advantage over blind biopsy in that it allows targeting of suspicious hypoechoic areas within the rest of the hyperechoic villous adenoma and is therefore likely to be more accurate. The procedure could be considered for use prior to radiotherapy in cases with biopsy-negative tumours.