This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gynaecological oncology, Subject name: Gynaecology & Obstetrics
The following statements are related to clear cell carcinoma of the vagina except : 
Select and explain. 
A. Common to those whose mothers were given diethylstilbestrol during early pregnancy, B. Vaginal adenosis may progress to this conditions, C. The middle one-third is the commonest site, D. May be multicentric and may involve even the cervix as well
C: The middle one-third is the commonest site
Answer: C: The middle one-third is the commonest site 
Explanation: clear cell adenocarcinoma of vagina: Found in adolescent girls who have a history of intrauterine exposure to diethylstilbestrol Incidence following DES exposure is 1:1000 may develop vaginal adenosis lesion usually involves upper third of anterior vaginal wall and cervix may be involved Treatment: radical hysterectomy,vaginectomy with pelvic lymphadenectomy. D.C.DUTTA'S TEXTBOOKOF GYNECOLOGY,Pg no:339,6th edition