There is no clear conclusion on how long it takes to detect malignant tumor of submandibular gland, and there are individual differences in different symptoms and the time of appearance, if there is a lump, tongue and skin abnormalities, it may suggest that there is a tumor of submandibular gland. 1. Appearance of lump: submandibular gland tumor is mostly manifested as a lump in the submandibular triangle, and when the tumor invades the periosteum of the mandible, it can be adhered to the body of the mandible and can not be moved. 2. Abnormalities of tongue: malignant tumor of submandibular gland can invade lingual nerve, causing tongue pain and numbness of tongue; it can invade hypoglossal nerve and cause restriction of tongue movement, with the affected side of the tongue being biased when stretching out the tongue, and it can also appear symptoms of tongue muscle atrophy and tongue muscle tremor. 3. Skin abnormality: malignant tumor of submandibular gland may be plate-like hard if it invades the skin. Malignant tumor of submandibular gland may have other symptoms, if the above symptoms occur, it is recommended to go to the hospital in time.