Influence of different criteria for abnormal lymph node size on reliability of computed tomography in patients with non-seminomatous testicular tumor.

The reliability of computed tomography (CT) using different criteria for abnormal size of retroperitoneal lymph nodes (5, 10, 15 mm in largest diameter) was evaluated prospectively in 90 consecutive patients with a non-seminomatous testicular tumor and lymph nodes less than 20 mm at CT. Correlation was made with histologic findings following retroperitoneal lymphadenectomy. Histologic examination revealed metastases in 38 patients (42%). Using a strict criterion of 15 mm for abnormal node size, sensitivity was 37%, specificity 98%, positive predictive value 93% and negative predictive value 68%. A relaxed criterion of 5 mm led to a sensitivity of 71%, specificity 67%, positive predictive value 61% and negative predictive value 76%. Overall accuracy was approximately 70% with the 5, 10 and 15 mm criteria for abnormal size. The inability of a normal scan to exclude metastases was the main limitation of CT.