We report a case of primary adenocarcinoma of the rete testis in a 55-year-old man with pulmonary metastases that were detected 11 months prior to the diagnosis of the primary lesion. Primary adenocarcinoma of the rete testis is an extremely rare malignant tumor with a poor outcome. The most common primary symptom is a scrotal mass, often accompanied by hydrocele and chronic epididymitis. The diagnosis is often delayed because of non-specific clinical presentation and symptoms. We cannot forget that rete testis is a possible primary site for a primary, unknown metastatic adenocarcinoma.