Sign of the groove is seen in:
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.
Lymphogranuloma venereum
Granuloma inguinale
Syphilis
Chancroid