Angiomatosis [ or Diffuse Hemangima] is a rare condition in which large segments of the body are involved by proliferating vessels. By now, some authers say that this lesion begins during early intrauterine life when the limb buds form, grow proportionately with the fetus, and consequently affect large areas of the trunk or extremity. The majority of angiomatoses present during childhood or infancy as swelling, induration, or discoloration of the affected area. The patient was 13 year old male and had no specific signs and symptoms except palpable mass on the left lateral chest wall from childhood and a painful tender mass on the posterior chest wall for 5 days before admission. The chest PA showed no abnormalities.The operation was done with the resection of left 10th rib and 9th and 10th intercostal muscles including masses and the ligation of the both intercostal and feeding vessels of the masses. The pathologic result was angiomatosis involving intercostal muscles and rib.