Contrast-enhanced ultrasound and real-time elastography for the diagnosis of benign Leydig cell tumors of the testis - a single center report on 13 cases.

Purpose: To describe sonomorphological features in testicular Leydig cell tumors (LCTs) with a special focus on contrast-enhanced ultrasonography (CEUS) and real-time elastography (RTE).

Patients And Methods: In a series of 186 patients with testicular surgery for neoplastic disease, 13 benign LCTs (in 12 patients) were histopathologically diagnosed. Preoperatively, all patients had been examined with a standardized protocol (high-resolution grayscale and color-coded ultrasonography, CEUS). 5 patients underwent RTE. In CEUS, the filling time of the lesion was compared to that of 14 size-matched germ cell tumors (GCT).

Results: 10/13 LCTs had a size of < 10 mm, and a sharply demarcated hypoechoic appearance was typical (10/13). Color-coded ultrasonography detected signals in 8 lesions, while CEUS showed clear hypervascularization in all. LCTs had a significantly shorter filling time than GCTs (p < 0.0005), with 9/13 LCTs being completely filled within 4 s. In RTE, all 5 examined lesions were clearly "harder" than the surrounding testicular tissue.

Conclusion: Contrary to some earlier reports, we could demonstrate marked hypervascularization in LCTs. This feature clearly allows for the differentiation of a small LCT from focal scars. However, it may only be visible on CEUS. In CEUS, LCT is suggested by the findings of a short filling time or by a circumferential vessel with a rapid centripetal filling, combined with a "harder" appearance in RTE. These features along with the findings of a small and peripherally situated hypoechoic tumor would justify an operative strategy with frozen section examination and possibly organ sparing surgery instead of orchiectomy.