The ivory vertebra: an approach to investigation and management based on two case studies.
METHODS
Case report.


OBJECTIVE
To report and discuss the natural evolution of fortuitously found solitary radiodense or "ivory" vertebrae in two asymptomatic patients; to review the existing literature concerning ivory vertebrae; and to provide a practical guide for the diagnostic and management approach to the fortuitous finding of ivory vertebrae in asymptomatic patients.


BACKGROUND
The asymptomatic and apparently idiopathic ivory vertebra is often a very problematic clinical situation. Previous studies have hypothesized that although several etiologies have been known to be responsible for producing ivory vertebrae, the most likely etiology, particularly for so-called "idiopathic" ivory vertebrae, is early and asymptomatic Paget's disease of bone.


METHODS
Two patients, each with an incidentally discovered ivory vertebra, were followed clinically over a period of 13 and 10 years, respectively. During this time the patients underwent a multitude of investigations in an attempt to identify the etiology of the ivory vertebra. After having eliminated ominous etiologies, the authors opted for a conservative approach to management (observation) so as to have a long-term follow-up of the patients and also attempt to determine the natural history of idiopathic solitary ivory vertebrae.


RESULTS
Despite the extensive workups, no etiology was ever found for either patient because the tests showed normal results for extended periods of time. Whereas in one patient Paget's disease of bone was suspected, no definitive confirmation for the presence of Paget's disease could be obtained, even on bone biopsy. Both patients remained entirely asymptomatic with respect to the ivory vertebra over the entire follow-up period.


CONCLUSIONS
Based on the observations from the present study as well as a review of the literature on the subject, a decision-making algorithm is put forth for the investigative approach as well as for the subsequent follow-up and management of patients with idiopathic and asymptomatic ivory vertebrae whereby, after baseline screening tests eliminate ominous pathology, observation and periodic clinical reassessment are advised until symptoms develop or until there are radiographic changes in the appearance of the ivory vertebra.
Carpineta
Lucia
L
Department of Diagnostic Radiology, McGill University, Montreal, Quebec, Canada.
Gagné
Michel
M
D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000002:abnormalities* / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D010001:Osteitis Deformans / Q000150:complications; D011859:Radiography; D013122:Spinal Diseases / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy; D013904:Thoracic Vertebrae / Q000002:abnormalities* / Q000000981:diagnostic imaging