Mutiple Spontaneous Rib Fractures in Patient with Cushing's Syndrome

Glucocorticoid (GC) excess, including Cushing's syndrome, is a common cause of secondary osteoporosis. Thirty to fifty percent of Cushing's syndrome patients experience non-traumatic fractures, which is often the presenting manifestation of Cushing's syndrome. However, there have been rare cases of Cushing's syndrome diagnosed only based upon bone manifestations. We describe a case of Cushing's syndrome that was diagnosed in a 44-year-old woman who initially visited our hospital due to multiple non-traumatic rib fractures. She did not exhibit any other manifestations of Cushing's syndrome such as moon face, buffalo hump or abdominal striae. Initially, we evaluated her for bone metastases from a cancer of unknown origin, but there was no evidence of metastatic cancer. Instead, we found a left adrenal incidentaloma. As a result of the hormone study, she was diagnosed as having Cushing's syndrome. Interestingly, her bony manifestation of Cushing's syndrome, which was evident in the bone scan and bone mineral densitometry, completely recovered after a left adrenalectomy. Therefore, the possibility of Cushing's syndrome as a cause of secondary osteoporosis should be considered in young patients with non-traumatic multiple fractures, with or without any other typical features of Cushing's syndrome.