男１４岁，３年前发现左足第２趾包块，因无疼痛，麻木等症状，未引起注意。近日来感包块逐渐增大，足趾畸形，酸胀。体检：右足第２趾背侧，外侧各可见有一约０．３ｃｍ×０．２ｃｍ大小包块，质硬，边界清楚，无压痛，表面光滑不移动。实验室各项检查均正常。Ｘ线检查：... The boy was 14 years old and he found his left toe mass 2 years ago. He did not notice because of pain and numbness. In recent days, the mass has gradually increased, with deformed toes and soreness. Physical examination: The dorsal side of the second toe of the right foot, with a mass of about 0.3cm x 0.2cm on each side of the right foot. The mass is hard, the boundary is clear, there is no tenderness, and the surface is smooth and does not move. All tests in the laboratory are normal. X-ray examination: ...