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 primary tumours are common in the vulva except : 
Select and explain. 
A. Adenocarcinoma, B. Basal cell carcinoma, C. Choriocarcinoma, D. Squamous cell carcinoma
C: Choriocarcinoma
Answer: C: Choriocarcinoma 
Explanation: Invasive lesions of vulva : Squamous cell carcinoma--most common 90% Melanoma 1-5% Adenocarcinoma 1% Sarcoma 2% Rodent ulcer or basal cell carcinoma 1%. Reference: Shaw's Textbook of Gynaecology 16th edition page no 475