A hard lump in the coronal groove resembling cartilage may be the cause of chancre, sclerosing lymphadenitis of the penis, and so on. 1. Hard chancre: it is a sexually transmitted disease caused by syphilis spirochete infection. Stage 1 syphilis may lead to the development of hard chancre in the genitals, causing painless, cartilaginous-textured hard lumps under the skin, and in some cases causing skin ulcers, which may be manifested as a hard lump in the groin of the crown that looks like a cartilage. 2. Penile sclerosing lymphadenitis: refers to the penile lymphatic vessels are subjected to external infection, trauma and other factors, caused by the blockage, inflammation, which leads to stiffness, protrusion, will also be manifested as the coronary groove has a hard lump like cartilage. There is a hard lump in the coronary groove like cartilage, there may be other reasons, you need to go to the hospital in time for further examination to clarify the cause.