A lump growing at the deepest part of the thigh root may be associated with diseases such as inguinal lymphadenitis, sebaceous cysts, lipomas and skin boils. 1. Inguinal lymphadenitis is an inflammatory change that occurs when the lymph nodes in the groin are affected by inflammatory factors, and is mainly characterized by enlargement of the lymph nodes in the groin, accompanied by pressure and pain. 2. Sebaceous cyst is a cystic lesion located under the skin, due to the sebaceous gland ducts are blocked after sebum secretion can not be discharged normally, resulting in fluid retention caused by the lesion without pain, no itching discomfort. 3. Lipoma is a benign lesion related to abnormal fat metabolism, which is mainly manifested as a small painless lump under the skin and has no adhesion to the skin. 4. Skin boil is an acute inflammation that occurs on the surface of the skin, the lesion is located in and around the hair follicle deep, it can be manifested as small bumps under the skin, and accompanied by redness, swelling and hot pain phenomenon. There may be other reasons for a pimple at the deepest part of the thigh root, and it is recommended that the patient go to the dermatology department of the hospital in time to find out the cause of the pimple and follow the doctor’s instructions for treatment.