This paper describes the case of an 83-year-old patient with hypertension, diabetes, obesity (body mass index - 38), congestive heart failure, and history of cardiac surgery, who was referred for a diagnostic-therapeutic decompression of a large, symptomatic ovarian cyst. Due to anatomical conditions, the only safe way was a transfundal puncture under mini-hysteroscopic and ultrasound guidance. A puncture with aspiration of 300 mL of serous fluid from the cyst was performed without technical problems and complications. Cytology showed no cancer cells in the examined liquid. Relief from pain and compression discomfort was achieved in the patient. This case shows the possibility of combining ultrasound and minimally invasive diagnostic methods like hysteroscopy in selected clinical situations.