This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Skin
Sign of the groove is seen in: 
Select and explain. 
A. Lymphogranuloma venereum, B. Granuloma inguinale, C. Syphilis, D. Chancroid
A: Lymphogranuloma venereum
Answer: A: Lymphogranuloma venereum 
Explanation: LGV is caused by Chlamydia trachomatis serovars L1, L2 and L3 and occurs in three stages. In the secondary stage or inguinal stage, enlargement of the femoral and inguinal lymph nodes separated by the inguinal ligament produces the 'sign of the groove'/sign of Greenblatt. NOTE: Ramrod /saxophone penis in males and Esthiomene in females occurs in the third stage of LGV. Ref: Sexually Transmitted infections, Bhushan Kumar, 2nd edition, pg 510-511.