The predominance of benign histology in small testicular masses

To evaluate the concordance between testicular tumor size and benign histology in order to identify a cut-off size, below which the rate of benign lesions would be highest.

During the years 1995-2008, we performed 131 consecutive testicular operations for testicular tumors. Ten of these were testicular preserving surgery, whereas the other 121 patients had radical orchiectomy. We searched for the rate of benign lesions in the following 3 groups of tumor diameter: 10 mm or less, 11-20 mm, and greater than 20 mm. ROC analysis was used to find the optimal size cut-off below which the rate of benign lesions would be highest.

Benign lesions were found in 11 patients (8%), including epidermoid cyst (n = 4), Leydig cell tumor (n = 3), fibrosis (n = 1), adenomatoid tumor (n = 2), and 1 patient with a simple cyst. Small tumor size strongly correlated with benign histology. The mean diameter of benign vs. malignant lesions was 15 mm and 41 mm, respectively (P < 0.05). The rate of benign lesions in tumors with a diameter of 10 mm or less, 11-20 mm and greater than 20 mm was 50%, 17%, and 2%, respectively. Receiver Operating characteristic (ROC) analysis with 87% sensitivity and 83% specificity revealed a cut-off value of 18.5 mm tumor diameter below which the proportion of benign lesions was 38.5% compared with 2% above it (P < 0.05).

While benign lesions comprise only 8% of all testicular tumors, their proportion among small lesions is much higher. With a size cut-off of 18.5 mm, 38.5% of smaller lesions are benign. These findings support consideration of testicular exploration for small testicular lesions aiming at preservation rather than predetermined radical orchiectomy.