The long strip-shaped lump at the root of thigh may be related to epidermoid cyst, lipoma and lymphadenitis. 1. Epidermoid cysts: mainly manifested as elevated skin lumps, mostly round or ovoid, which can occur in any part of the body, and some patients may have long strip-shaped lumps at the root of thighs. Its cause may be embryonic ectopic, trauma and other factors. 2. Lipoma: mainly manifested as one or more lumps of different sizes under the skin, mostly seen in the neck, shoulder, thighs, buttocks and other places. Its cause may be caused by the activation of tumor-causing factors, genetic, chronic inflammation and other factors may also induce the disease. 3. Lymphadenitis: mainly manifested as enlarged lymph nodes, in severe cases, multiple lymph nodes will be enlarged, which can be fused to form a larger lump, and some patients will feel a long strip-shaped lump at the root of the thigh. Its etiology may be related to germs infection, such as hemolytic streptococcus, staphylococcus aureus, etc.; some of the lymph node enlargement is related to tumors and so on. There are many causes for the long strip-shaped lump at the root of the thigh, and patients are advised to seek medical examination to clarify the cause.