[Ultrasound characteristics of testicular Leydig cell tumors , , , 1.]

OBJECTIVE: To explore the color Doppler ultrasonic characteristics of testicular Leydig cell tumors (LCT) and improve the clinical diagnosis of the disease. METHODS: We retrospectively analyzed 4 cases of testicular LCT diagnosed and treated in our hospital and summarized the experience in the ultrasonic diagnosis of LCT with a review of the relevant literature. RESULTS: All the 4 testicular LCTs were solitary and quasi-round, 1 in the left and 3 in the right. The smallest mass was 1.8 × 1.5 cm and the largest 3.1 × 2.5 cm, and 2 were complicated by hydrocele of tunica vaginalis. The margins of tumors were distinct in 2 cases and indistinct in 1, and changed from distinct to indistinct in another during the follow-up. Hypoechoes were revealed in all the 4 cases in ultrasonography, 2 with abundant internal blood flow, 1 with abundant peripheral blood flow, and the other with abundant internal blood flow changed from circular blood flow surrounding the mass. CONCLUSIONS: A typical sporadic LCT was ultrasonically manifested as an isolated hypoechoic infracentimetric mass with a clear demarcation from the adjacent pulp. It exhibited intrinsic hypervascularization associated with a typical peripheral rim pattern. Larger lesions more often presented a lobulated shape and intense hypervascularization. Although these ultrasonic characteristics do not reveal the nature of LCT with certainty, they can help the surgeon with the decision on testis-sparing surgery or perhaps even on the active monitoring for the smallest lesions in a population with impaired fertility.

CEUS Time Intensity Curves in the Differentiation Between Leydig Cell Carcinoma and Seminoma: A Multicenter Study.

PURPOSE: Ultrasound (US) is the main imaging technique in the assessment of testicular masses, as it has proved to be highly accurate in the visualization of these pathologies. Identification of a Leydig cell tumor is essential since the lesion is benign in 90% of cases. The aim of this multicenter study is to assess the effectiveness of contrast-enhanced ultrasound (CEUS) in differentiating Leydig cell tumors from seminoma using qualitative and quantitative features. MATERIALS AND METHODS: From February 2011 to December 2013, 31 patients (mean age: 34 years; range: 25 - 52) were recruited for this prospective study. Three of them were monorchid. Therefore, a total of 59 testicles were assessed. All patients underwent grayscale US, color Doppler ultrasound (CDUS), CEUS and orchiectomy. The paired one-tailed Student's t-test was carried out to differentiate between Leydig cell tumors and seminomas. RESULTS: 31 lesions suspicious for malignancy were hypoechoic on grayscale US while they did not show a typical pattern on CDUS. CEUS qualitative analysis, based on contrast enhancement pattern, during the arterial and venous phases, did not allow discrimination of Leydig cell tumors from seminoma. Quantitative analysis of time-intensity curves (TICs) demonstrated that only three parameters presented statistical significance, i. e. wash-in rate (WiR) p = 0.014, peak enhancement (PE) p = 0.001 and time to peak (TTP) p = 0.003. CONCLUSION: The vascular bed of a Leydig cell tumor is wider and the blood flow velocity is higher than that of a seminoma due to more regular neovascularization. In contrast, a seminoma presents large areas of necrosis due to irregular neovascularization. This explains the different PE and WiR values. Further studies involving larger patient populations are mandatory to confirm these encouraging preliminary results.

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.

Growth and composition of a transplantable murine Leydig cell tumor.

C57BL/6J mice inoculated sc with 50 mg of a transplantable Leydig cell tumor (M5480) demonstrated a reproducible pattern of slow tumor growth up to day 10 followed by rapid growth at the rate of approximately 0.5 g per day through day 27. The mean survival time of tumor-bearing mice was 33 days, when tumor weight accounted for more than 25% of total body weight. The rapid increase in weight occurring around day 10 resulted largely from a 20-fold increase in the quantity of extravasated blood inside the tumor, which in turn promoted a 50% reduction in host hematocrit. Sustained enlargement of M5480 during the third and fourth weeks of growth was supported by proliferation of tumor cells. Apart from blood-filled cavities, over 90% of the tumor consisted of neoplastic Leydig cells exhibiting generalized cytoplasmic features usually associated with mitotic activity. An activated macrophage was the next most abundant cell type, accounting for 2-3% of the nucleated cell mass. The remaining 3% was occupied by vascular elements, leukocytes, and giant cells. Depending on the age of the tumor, varying proportions of the cell population showed signs of anoxic degeneration. Degenerate cells were minimal at day 14, accounting for less than 4% of the total population, and maximal beyond day 21, when they occupied more than 50% of the cell mass.