The Gorham-Stout Syndrome (Gorham's massive osteolysis) is a rare condition in which spontaneous, progressive resorption of bone occurs. The aetiology is poorly understood. We report six cases of the condition and present evidence that osteolysis is due to an increased number of stimulated osteoclasts. This suggests that early potent antiresorptive therapy such as with calcitonin or bisphosphonates may prevent local progressive osteolysis.

In 20 intact and 20 parathyroidectomized female Sprague-Dawley rats, holes with a diameter of 1.8 mm were bored into the proximal third of the tibia. Half the animals served as controls and received the vehicle, the remainder received daily subcutaneous injections of 100 MRCmU calcitonin in 5 % gelatin. Tetracycline labelling was performed weekly. 5 animals from each group were sacrificed after 3 weeks, the other 5 after 6 weeks. Nondecalcified ground sections through the center of the holes were evaluated with an integration ocular; the surface of the newly formed bone was compared with the original size of the defect. The course of the regeneration for the control animals was in agreement with previous data in the literature. Calcitonin treatment produced a distinct acceleration of the healing process. Presumably, the hormone does not only act via inhibition of bone resorption, but also by stimulating the activity of osteoblasts and by increasing the mineralization of the osteoid seams.

T he Gorham-Stout Syndrome (Gorham's massive osteolysis) is a rare condition in which spontaneous, progressive resorption of bone occurs. The aetiology is poorly understood. We report six cases of the condition and present evidence that osteolysis is due to an increased number of stimulated osteoclasts. This suggests that early potent antiresorptive therapy such as with calcitonin or bisphosphonates may prevent local progressive osteolysis.

The clinical and morphological characteristics of Shwachman's syndrome (exocrine pancreatic insufficiency, pancytopenia, skeletal changes) were observed in a boy who, at the age of 8 years, developed a juvenile form of chronic myeloic leukemia which did not respond to cytostatic treatment. Autopsy revealed a striking lipomatous atrophy of the pancreas, defects in the ossification zones of the bones and marked dwarfism. In addition there was leukaemic infiltration of the pancreas, the spleen, the liver and the lymph nodes. The association of Shwachman's syndrome with leukaemia is a rare, but remarkable complication of this entity because of its relationship to the preceeding pancytopenia. Thorough follow-up of the haematological status of patients with Shwachman's syndrome is recommended.

The present study deals with qualitative und quantitative analysis of osteoclastic bone resorption in metastatic bone disease. 267 cases were examined histomorphologically and divided into three developmental stages. In the first 'phase of early appearance' no bone resorption takes place. The stimulation of osteoclastic resorption in the surroundings of tumour tissue is typical in the second 'phase of interaction'. Pressure atrophy, aseptic necrosis and osteolysis by the tumour cells themselves are other mechanisms of bone destruction in the last 'phase of carcinomatosis'. Because osteoclasts are exclusively responsible for the loss of bone tissue in the 'phase of interaction', this stage is suited for precise quantitative analysis of osteoclastic resorption. 24 pure osteolytic secondary bone tumours of various primary lesions were examined histomorphometrically. The numerical values were compared with each other and with standard values of healthy individuals. In contrast with normal bone tissue the fractional resorption surfaces und osteoclast indices increase in metastases. Activated osteoclasts are larger and have more nuclei. The numbers of osteoclast index and nuclei per osteoclast are significantly higher in renal than in breast carcinoma. Osteoclasts can be activated in distances of more than 500 micron from tumour tissue. The mean stimulation distance in metastasis from squamous cell carcinoma is markedly higher than in secondary bone tumours of breast carcinoma. Several osteoclast activating substances and divers mechanisms of stimulation might be responsible for different numerical values of morphometric parameters in metastases from various primary malignancies.