A lump on the penis may be caused by sebaceous cyst, prepuce glans, warts, penile cancer and other factors. 1. Sebaceous cysts: prolonged failure to clean the penile area may lead to sebaceous gland duct blockage, sebaceous gland secretion discharge is not smooth, may induce sebaceous cysts, in the cyst is small, the clinical symptoms are not obvious, when the cyst is large, it may cause pain and other symptoms. 2. circumcision: may be related to poor hygiene, can make the penile area of inflammation and infection, due to inflammatory substances stimulation, can make the local pus pimples, may also be accompanied by itching, tingling, redness and other symptoms. 3. Condyloma acuminatum: usually caused by unclean sexual life, can make the penis localized cauliflower pattern protrusion, accompanied by mild itching and tingling, and has a certain degree of contagious. 4. Penile cancer: it may be related to chronic inflammation stimulation, prolonged smoking and other factors, which can make the penis appear small and hard lumps, similar to small pimples, and the volume will gradually increase, and there may be pain, itching, bleeding, pus and other symptoms. A lump on the penis, and there are other abnormal manifestations, may be the existence of disease factors, it is recommended to go to the hospital urology department for appropriate examination and treatment.