[Bone metastases of colonic and rectal neoplasms. Apropos of 11 cases].

The authors report 11 personal cases and discuss the characteristics of bony metastases in carcinoma of the colon and rectum. The frequency of these metastases is fairly low (1.3% of all cases of bony metastases) as tumours of the large intestine do not tend to migrate to the bones. Sometimes bony metastases are the presenting symptom but, usually the metastases occur within 5 years of the diagnosis of the primary tumour. The clinical picture shows no special characteristics. Radiologically, these bony metastases may be either single or multiple. Their distribution recalls that of other metastases in the bones with a few differences, however. The special frequence of pelvic involvement, distal localisations (hands or feet) are not exceptional. Metastases usually give rise to osteolysis. The mixed appearances are, however, not rare, and usually give a pseudo-sarcomatous appearance, with invasion of the soft parts and very marked periosteal reaction. Sometimes, bony condensation may be noted. The treatment of rectal and colonic cancer with bony metastases, is disappointing as the disease is always fatal within a relatively short period, usually less than one year after the diagnosis of the bone involvement. The histological appearances of the bony lesions depend on differenciation of the tumour and the characteristics of the neighbouring bony abnormalities which, in our experience, usually include both osteolysis and osteogenesis.