The etiology of soft fibroma is not clear, it may be caused by HPV virus, or it may be related to diabetes, obesity and other factors. 1. HPV virus: for low-risk types of human papillomavirus, such as HPV11, HPV6, etc., there may be a certain link with the development of soft fibroid tumor. 2. Diabetes mellitus: Chondromatosis may have some connection with insulin level in peripheral circulation, so the chance of diabetes mellitus patients will be increased. 3. Obesity: Obese people are more likely to develop chondroma than other people, so obesity may also induce chondroma. The appearance of skin lesions similar to chondroma can go to the regular hospital for examination and clear diagnosis.