Multiple Pathologic Fractures Mimicking Bone Metastases In a Patient With Cushing's Syndrome

Abstract

The deteriorating effects of corticosteroids on bone structure and metabolism have been well documented since they were first reported by Harvey Cushing in 1932. The main effects of corticosteroids causing osteoporosis Include: direct suppression of osteoblasts, indirect stimulation of osteoclasts mediated by cytokinins and prostaglandins, and secondary hyperparathyroidism due to both decreased gut absorption and increased urinary excretion of calcium. Corticosteroids also have a suppressive effect on both gonadal function, adrenal androgens In women, as well as catabolic effects on muscle and bone matrix proteins. Therefore, high corticosteroid levels result in pathologic bone fractures. The authors describe a 33-year-old woman with adrenal Cushing's syndrome who had multiple pathologic fractures, including bilateral pelvic fractures, which mimicked bone metastases on bone scintigraphy. These findings resolved completely after the resection of the adrenal tumor. When a patient presents with multiple pathologic bone fractures, demonstrated on both radiography and scintigraphy, one should consider a diagnosis of metabolic bone disease, as well as other diagnostic possibilities.