Chinese Medical Journal

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METASTATIC CARCINOMA OF HUMERUS 65

showed the presence of tumor cells with clusters of signet ring cells. Though no surgical exploration was done, the roentgenogram of the stomach and the presence of Krukenberg’s tumors of ovaries as diagnosed by our gynecologist strongly suggested that the primary lesion was in the stomach.

In all our cases, the site of metastases gave rise to early symptoms. The first 2 cases had pathological fractures of the humerus before the exact diagnosis was made. The third case gave the symptoms of pain and soreness over the back, shoulder and the cervical region instead of in the gastrointestinal tract. These facts show that metastatic lesions in bones might arise from concealed lesions in the gastrointestinal tract, whose investigation is of much importance.

Moreover, in some cases of carcinoma of the stomach with definite bone metastases, clinical evidence is cften lacking, and even roentgenological examination may be negative. Lawton’s(9) 10 cases of carcinoma of stomach which showed bone metastasis clinically were not seen in the x-ray film. Metastatic lesions were verified in 3 of them at necropsy. Thus, cases of bone metastases from carcinoma of the stomach and the rectum are probably more common than generally supposed.

The following four anatomical pathways(10) are possible routes of spread of carcinomas of the gastrointestinal tract: direct extension, the lymph vessels, the blood stream, and transplantation through the peritoneal cavity. Carnett and Howell(11) support the theory of lymphatic permeation in case of neoplastic extension within the abdomen. Mechling(12) asserts that the spread is either direct through the blood stream or secondarily through the embolus formation (e.g. in the lung with secondary growth and further spread therefrom) or the result of the passage of a single cancer cell through the lung capillaries into the general circulation. He believes that the tumor cell emboli entering the thoracic duct from the blood stream may produce the bizarre metastatic lesion. Batson(13) believes that metastasis may occur through the vertebral veins. The vertebral veins, according to him, form a separate system, having a rich, valveless ramification and connections, so that metastasis can occur without involvement of the heart and lungs. Geschickter and Copeland(6) state that, in view of cases with metastasis to the long bones as the humerus and the femur but without invasion of the intervening structures between the primary focus and the distant metastasis, one is forced to consider metastasis occurring by way of the blood stream. But it seems that each case should be considered individually. In our

cases the hematogenous or lymphatic route appears to be the more likely channel of spread.