Although testicular cancers are relatively rare, accounting for only 1% to 2% of worldwide male cancer diagnoses, it is the most common malignancy in men aged 15 to 44. Testicular tumors may originate from any of the cell types present in the testes and generally fall into the two competing categories of germ cell tumors, of which about 95% of testicular cancer is composed, and sex cord-stromal tumors which comprise the remaining 5% in adults. Of the 5% of sex cord-stromal tumors, Leydig cell tumors are the most common and derive from the same Leydig cells that normally reside in the interstitium of testicles and secrete testosterone in the presence of luteinizing hormone. They are generally benign tumors with only 5% to 10% being considered malignant and have a bimodal distribution with peaks in the prepubertal age group and between the ages of 30 to 60. Due to Leydig cells' hormonally active properties, they can present with precocious puberty, breast tenderness, or gynecomastia.