[Stimulation of osteoblasts in skeletal metastases--a quantitative study]

In almost 80% of all skeletal metastases of carcinoma of the prostate, osteoneogenesis by "normal" osteoblasts can be detected in the surrounding tissue. The object of the present study was to perform a quantitative histomorphometric analysis of this local osteoblast stimulation. In tissue with metastases, the relative proportion of osteoid and mineralized bone tissue per unit of volume (Vv = 46%) was three times higher than the norm (Vv = 15%). Although the lamellar spongiosa (Pm = 19%) was only slightly higher than the physiological values (Pm = 15%), a considerable increase in fibrous bone tissue (PFK = 39%) was found (normal value: 1-2%). The volumetric density of the osteoid (POST = 7%) had also increased (normal value: 7%). While the mean width of the trabecula of the lamellar spongiosa was within normal range (dTRAB/LK = 136 microns), appositional accumulation of a 62 microns thick fibrous bone layer resulted in a distinct tumefaction of the trabeculae. The width of the osteoid border (dapp.OST) was 22 microns (normal value: 13 microns). The majority of the activated osteoblasts were 30-150 microns from the neighboring tumor cells.