Mixed epithelial and stromal tumor (MEST) is a rare neoplasm of the kidney, affecting mostly women at menopausal age. While few cases of malignant transformation have been described in the literature, MEST is usually considered a benign tumor with minimal risk of local recurrence or distance metastases. The current study presents a case of a 18-year old male patient with a cystic tumor of the left kidney incidentally diagnosed on magnetic resonance imaging of the heart performed for other reasons. The patient underwent a partial nephrectomy, with perioperative course being uneventful. The pathology report revealed MEST of the kidney. No local recurrence nor disease progression have been observed in the patient during the one-year follow-up period. The present case report is evidence that may help in developing guidelines on the management of patients with benign renal masses.