Risk Factors and Treatment Outcomes of 1,375 Patients with Testicular Leydig Cell Tumors: Analysis of Published Case Series Data

Leydig cell tumors are rare but they are the most common nongerm cell testicular tumors. Only limited evidence exists for reliably differentiating between benign and malignant Leydig cell tumors and for optimally managing the different types and stages of this rare disease. In this review we synthesize the available evidence on the clinical presentation and clinicopathological characteristics associated with Leydig cell tumor malignancy and management.We analyzed published case series data on Leydig cell tumors. The association between clinicopathological variables and the presence of metastatic disease was assessed using regression analyses.We included 357 reports, reviewing available data from 1,375 patients (median age 34 years). Testis sparing surgery was performed in 463 patients. Local recurrence after testis sparing surgery occurred in 8 of 121 (7%) patients with available followup information. Metastases were found in 101 patients and were most often located in the retroperitoneal lymph nodes (60%), lungs (38%) and/or liver (29%). The multivariable models with or without multiple imputation predicting metastatic disease included older age, larger tumor size, presence of any adverse factor (larger tumor diameter, necrosis, angiolymphatic invasion, pleomorphism, high mitotic index, atypia) and any protective factor (Reinke crystals, lipofuscin pigments, gynecomastia) with model AUCs of 0.93. Durable remission after resection of metastases or use of platinum based chemotherapy was rarely seen.Our risk tables using clinicopathological parameters can help identify patients with malignant tumors. These patients should undergo disease staging and be followed or receive further treatment. In some patients with metastatic disease surgical and systemic treatment might result in disease control.