The pathogenic microorganism of oral tuberculous ulcers is Mycobacterium tuberculosis, and lesions are uncommon in the clinic. The lesions occur anywhere in the oral mucosa, but are commonly found on the tongue. The ulcer is usually well-defined or linear and appears as a superficial, slightly concave and flat ulcer with a small amount of purulent exudate at the base, and a dark red mulberry-like granuloma is visible after removal of the exudate. The texture of the ulcer base may be similar to that of the surrounding normal mucosal tissue. When the nodules break down, they become dark red mulberry-like granulomas, and the ulcer then enlarges. Because the nodules do not have a fixed location at the edge of the ulcer, the shape of the tuberculous ulcer is usually irregular and the patient has varying degrees of pain, with the ulcer on the tongue being the most obvious. The ulcer may also be sclerotic, but this is generally less pronounced than malignant changes or other infectious granulomas. In addition, if a patient with pulmonary tuberculosis has very poor resistance, lesions may develop at the mucosal-skin junction of their mouth and lips. The early stage is a superficial granulomatous ulcer with a tendency to develop into extensive tissue destruction and produce extensive deformities, called cutaneous oral tuberculosis.