Unless there is a clinical suspicion of hyperparathyroidism, radiographs of other areas, such as the hands, showing the classic stigmata of the disease, are not routinely requested. Unfortunately, if the interpretation of the imaging fails to identify the hyperparathyroidism, the pathologist may compound the misdiagnosis. It is for this reason that the histology of the proximal humeral lesion in case 2 was reported as GCT or solid ABC, even on review. In an ideal situation the serum calcium level would be available at the time of reporting the imaging. All too often, in the interests of prompt assessment of the patient, imaging investigations and blood tests are ordered simultaneously.
Primary hyperparathyroidism presenting with brown tumour is now unusual.
Clearly, our unit has a biased referral pattern because of the specialist nature of orthopaedic oncology. In the 3-year period that these cases were seen, a total of 335 new primary sarcomas of bone and 65 GCTs were referred to our unit for diagnosis and management. As compared with brown tumours, primary sarcomas of bone were over 100 times more common and GCT over 20 times more common. It is interesting to speculate as to whether MR imaging may have a role in future in the management of brown tumour. It was recognised, well before the introduction of MR imaging, that a minority of brown tumours fail to heal after successful treatment of the underlying condition.