1. Department of Obstetrics and Gynecology, Toyooka Hospital, Toyooka, Hyogo 668-8501, Japan
2. Department of Diagnostic Pathology, Toyooka Hospital, Toyooka, Hyogo 668-8501, Japan
3. Department of Diagnostic Pathology, Kakogawa Central City Hospital, Kakogawa, Hyogo 675-8611, Japan
4. Department of Radiology, Toyooka Hospital, Toyooka, Hyogo 668‑8501, Japan
5. Professor Emeritus, Kansai Medical University, Hirakata, Osaka 573-1010, Japan