There is a hard lump inside the thigh root which may be related to enlarged lymph nodes, inguinal hernia, soft tissue tumors, etc., and it should be consulted in time to find out the cause of the disease. 1. Enlarged lymph nodes: a hard lump inside the thigh root may be caused by enlarged lymph nodes in the inguinal area, which can be caused by lymphatic inflammation, lymphatic tuberculosis, lymph node metastasis of malignant tumors, etc., and is usually accompanied by local pain, generalized fever and other symptoms. 2. Inguinal hernia: located in the triangular area at the root of the thigh, it can occur when there is a sudden increase in intra-abdominal pressure such as strong labor or defecation. Early patients can appear inguinal area protruding mass, accompanied by mild swelling, hernia gradually increased, can cause abdominal wall damage, can also occur incarceration or strangulation, resulting in intestinal obstruction. 3. Soft tissue tumors: including fibrous tissue, adipose tissue, rhabdomyosarcoma tissue and tumors of various parenchymal organ supportive tissues. Patients may have painless lumps, in which the lumps are harder in the tumor with more fibers and smooth muscles, and may be accompanied by pain and other symptoms. In addition, there is a hard lump inside the thigh root may also be sebaceous cysts, folliculitis and other diseases, but this symptom alone is not enough to diagnose the disease, and promptly go to the hospital general surgery or dermatology department, under the guidance of the doctor for examination and treatment.