There are multiple causes for small, palpable masses under the skin, and I recommend that you see your doctor
for a formal evaluation to elucidate the cause of the mass on your leg. Given the location of the lesion, sexually transmitted diseases should be considered. Human papilloma virus (HPV) is the pathogen that causes genital warts
, which can sometimes present as small cauliflower-like masses on the skin in the groin region. If there is ulceration of the skin, then syphillis and herpes can also cause lesions in this area. There are multiple other causes of palpable lumps. One of the most common diagnoses is lipoma, which is a benign growth of fat tissue in the subcutaneous layer under the skin. Lipomas feel like small, rounded, mobile and firm masses. They are usually painless and can be monitored. In rare cases, malignancy of the soft tissues can present as a small mass such as sarcoma. However, these are quite rare. They often present as rapidly growing and can be painful. Other causes include sub dermal nevi, which are essentially moles within the dermal layer of skin. Finally, infection of the skin such as ingrown or abscess
can also lead to painful lumps on this skin. Your doctor will be able to evaluate your lesion and determine what may be the cause of the mass on your leg.