CT-guided needle biopsy of deep pelvic lesions by extraperitoneal approach through iliopsoas muscle

We report our experience with computed tomography (CT)-guided coaxial needle biopsy of deep pelvic lesions by an extraperitoneal approach through the iliopsoas muscle, using a curved needle for difficult-to-reach lesions. We reviewed the records of all patients with pelvic masses who underwent CT-guided percutaneous biopsy via iliopsoas muscle between January 1999 and December 2001. Direct anterior or posterior approach to the lesion was obstructed by bowel, bladder, vessels, or bones in all patients. An 18-gauge guide needle was advanced through the iliopsoas muscle and a 22-gauge Chiba needle was used to perform the biopsy. A custom-tailored curved 22-g needle was used in 17 procedures when the location of the iliac vessels and the slope of the iliac wing obstructed a straight path to the lesion. Fifty-three patients underwent 57 CT-guided needle biopsies during the study period. The lesions comprised obturator (n = 25), internal iliac (n = 11), anterior external iliac (n = 4), and common iliac nodes (n = 4); soft tissue masses along pelvic side-wall (n = 6); adnexal lesions (n = 5); a loculated fluid collection, and a perirectal node. All lesions were safely accessed, and major vessels and viscera were avoided in all cases. Of the 57 biopsies, 53 (93%) yielded diagnostic specimens. No major complications were encountered. CT-guided coaxial needle biopsy by an anterolateral approach through the iliopsoas muscle, with the use of a curved needle in selected cases is safe and effective for obtaining samples from deep pelvic lesions.