RESUMO
Although bone metastases can be found commonly in some malignant tumours, diagnosing a primary malignancy site is not a usual event. Secondary signet ring cell carcinoma of the bone is a very rare tumour. We present a case with pure metastatlc signet ring cell carcinoma of the bone, with an uncertain primary site. A 48-year old man was admitted with Rt thigh swelling and inability to walk. One of first diagnostic effort performed was histopathological examination that revealed a metastatic signet ring cell carcinoma, compressing the regional lymphatics. To our knowledge, in Sudan literature, we believe that this case is the first report of metastatic signet ring cell carcinoma of the proximal femur. Because of the very short survival of many patients, all investigational procedures should be judged in view of their rationality, and should be focused on treatable primary tumours