Incidence and histopathology of metastases of mammary carcinoma in biopsies from the posterior iliac crest.

Bone marrow biopsies were taken from the posterior iliac crest in 532 women with unilateral breast cancer. Metastatic tumors were found in 10% of the biopsies. In a group with negative radiological examinations of the skeleton, the incidence of positive bone marrow biopsies was 1.6%. In a group with radiologically detectable metastases in the skeleton 28% of the biopsies were positive. In the latter group 43 out of 45 individuals with positive biopsies had negative x-rays of the pelvis. Histopathologically, 19% of the metastatic tumors were osteolytic, 65% were osteoblastic and 16% did not influence the bone structure. The fibrous reaction in and around the bone marrow tumors was similar to that found in the primary tumor. In 74% the morphological pattern was consistent throughout the biopsy, whereas in 26% the morphology was different in different parts of the biopsy. No specific histopathology was observed in the individuals with negative radiological examinations of the skeleton. Bone marrow biopsy of the posterior iliac crest does not seem to be helpful as a routine method in the initial staging of mammary carcinoma but may contribute to establish the degree of tumor spread in individuals with positive or suspicious x-ray of the skeleton.