Endocrine Abstracts

Introduction: A brown tumor is a rare osteolytic non-neoplastic lesion, due to an anomaly of bone metabolism, occuring in primary, secondary or tertiary hyperparathyroidism.

This is a case about a brown tumor with multiple localizations seen in primary hyperparathyroidism.

Observation: A 42 year old patient,with a history of Behçet disease diagnosed at the age of 38, is hospitalized in our department for the management of a fortuitously diagnosed hypercalcemia at 3.11 mmom/l. The treatment consisted in a rehydration, resulting in the progressive decrease of hypercalcemia.

A primary hyperparathyroidism was diagnosed based on a hypercalcemia reaching 3.21 mmol/l, hypophosphatemia at 0.6 mmol/l, an elevated level of PTH at 2278 pg/ml (N : 15–72), a hypercalciuria at 11.8 mmol/24 h. A vitamin D deficiency at 8.1 mg/l was also diagnosed. A cervical ultrasound and a Sestamibi parathyroid scintigraphy were done concluding to a parathyroid adenoma localized in the right inferior pole. A study of the repercussions of the hyperparathyroidism has shown an osteoporosis, a medullary nephrocalcinosis and a right renal lithiasis.

A surgical indication was established, after a preoperative preparation by vitamine D and bisphosphonates. After the surgey, the patient developed a hungrybone syndrome, treated by a calcium and vitamin D supplementation. A month after that, the patient developed pain in both legs, leading to the discovery of multiple osteolytic images in the both tibias, on the radiography. A bones scintigraphy showed multiple pathological fixations in the skull, right clavicle, the sternum, rib cage, lower extremity of the left femur and the two tibias, all in favor of brown tumors. The patient refused to do a bone biopsy and was treated by bisphosphonates.

Discussion and conclusion: Brown tumors complicate 4.5 % of cases of primary hyperparathyroidism. They are the result of an important osteoclastic activity. The most common localizations are the ribs,clavicles, pelvicgirdle and the mandible. The localization in the long bones is rare. In the case of this patient, there are multiple localizations. These benign bone tumors pose a problem of differential diagnosis with osteolytic metastases. Biopsy, if realised, show multinucleated giant cells, but these latters are not specific