INTRODUCTION Retinoblastoma (RB) is the most common eye tumour in children and is curable. Patients with hereditary RB have increased risk of developing additional tumours, predominantly sarcomas. The published results on the treatment of bilateral RB have shown that 10-15% of patients develop second primary tumours (SPT). Average latent period, e.g. the period from the diagnosis of bilateral RB to the appearance of SPT is 10.4 years. In the literature, the appearance of second benign tumours in patients suffering from unilateral and bilateral RB has not been analyzed separately. However, the size and the location of benign tumours can cause serious complications. CASE OUTLINE We present a 14-year-old female patient. At age 4 years, her left eye was enucleated owing to unilateral RB. In the postoperative period, she did not undergo irradiation, nor did she receive chemotherapy. On her regular ophthalmologic check-up, the patient informed us that her belly was 'swelling' over the past four months. She had no pains or other complaints. The abdomen was significantly above the level of the chest, tense, painless on palpation, with obvious fluctuations. Abdominal echosonography confirmed the presence of a huge multilocular cystic formation, 19×18 cm in diameter, spreading from the pelvis to the epigastrium, and pressing the liver and spleen. A cyst of 4.7 cm in diameter was observed in the upper pole of the left kidney. Both the gigantic cyst of the left ovary (weighing 10300 g) and the left suprarenal cyst (weighing 30g) were removed. CONCLUSION We report a patient who developed second nonocular tumors (ovarian and suprarenal cysts) after successful treatment of unilateral RB. Patients treated for RB (hereditary and non-hereditary) should be checked regularly and meticulously. Early recognition of tumours, treatment can prevent possible complications.