Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant disorder that typically displays familial inheritance. Gastrointestinal polyposis and cutaneous pigmentation is a classic presentation of this syndrome. The reported lifetime cumulative cancer risk in PJS patients is >76% when compared with the general public with females affected more often than males. The prepubertal testicular tumor registry found Sertoli cell tumors (SCTs) to compose approximately 1% of all pediatric solid tumors. Prepubertal testicular masses are relatively rare. Only a small number of SCT cases have been reported in the first decade of life. The concurrence of PJS and feminizing SCTs of the testes is an increasingly recognized cause of prepubertal gynecomastia. The testicular lesions observed in patients with PJS primarily represent multifocal intratubular large cell hyalinizing SCTs with a distinct morphology that differs from large cell calcifying SCTs and sex cord tumors with annular tubules. Here, we describe the diagnosis and treatment course of a 4-year-old male with a SCT of the testes and diagnosis of PJS.