Predictive value of percutaneous imaging-guided biopsy of peritoneal and omental masses: results in 111 patients.

OBJECTIVE The objective of our study was to determine the predictive value of percutaneous imaging-guided biopsy of peritoneal and omental masses. MATERIALS AND METHODS A retrospective study of 111 patients who underwent biopsy of a peritoneal or omental mass from 1998 to 2006 was performed. Biopsy results were classified as diagnostic (malignant or benign) or nondiagnostic. Sensitivity, specificity, and negative predictive value (NPV) were calculated for all patients, and the Fisher-Freeman-Halton exact test was used to determine whether test characteristics varied by patient history (presence of a known cancer), mass size (<4 cm vs >or= 4 cm), and needle size (biopsies with fine needles vs biopsies with fine and large needles). RESULTS The overall diagnostic rate was 89% (99/111); there were 86 true-positive, one false-positive, six true-negative, and six false-negative results (sensitivity, 93% [86/92]; specificity, 86% [6/7]; NPV, 50% [6/12]). There were no statistically significant differences between patients with and without known cancer. Among 79 patients with known cancer, 52 (66%) had metastatic disease from the known cancer; in eight (10%) patients, the biopsy result yielded new primary cancers. Of 32 patients with no known cancer, 23 (72%) had malignant results. Biopsy test characteristics did not differ with respect to mass or needle size. Minor complications were seen in three (3%) patients. CONCLUSION Percutaneous imaging-guided biopsy of peritoneal and omental masses is a safe, effective procedure that is useful in clinical practice. A second malignancy was revealed in a substantial number of patients with a known primary cancer. A new malignancy was diagnosed in most patients without a history of cancer.