Endocrine Abstracts

Background: Nowadays, primary hyperparathyroidism is usually diagnosed incidentally, in asymptomatic patients, while only around 15% of patients present the classical manifestations. Osteoclastoma, a benign bone lesion, is usually the late manifestation of hyperparathyroidism.

Objective: We present the case of a 52 years old female (non-menopausal) recently diagnosed with ulnar osteoclastoma, primary hyperparathyroidism and secondary osteoporosis.

Material and methods: The patient had a history of pathological fracture of right ulna secondary to osteoclastoma; she had undergone surgery removal of the tumor followed by bone grafting and screw fixation one year before being admitted to our hospital. At admission to our hospital, the patient had walking difficulties caused by the harvesting of fibular graft. Except for this, the physical exam was unremarkable. Laboratory findings revealed hypercalcemia (11.8 mg/dl), hypophosphatemia (2.2 mg/dl), low 25(OH)vitamin D level (6.45 ng/ml), high level of PTH (811.7 pg/ml) and elevated level of 24-h urinary calcium excretion (374 mg/24 h). Screening for multiple endocrine neoplasia type 1 and type 2A was negative. Neck ultrasonography revealed a hypoechoic mass (2.5/1 cm) suggestive for a lower right parathyroid adenoma. DXA of the lumbar spine, left hip and left radius showed low mineral bone density: L1–L3 T score=−3.8 S.D., Z score=−3.2 S.D., left hip (neck) T score=−3 S.D., Z score=−2.3 SD, distal left radius T score=−2.1 S.D. Z score=−1.9 S.D.. Abdominal ultrasonography showed bilateral renal microlithiasis.

Results: Clinical and paraclinical findings led to the diagnosis of primary hyperparathyroidism that eventually caused ulnar osteoclastoma and secondary osteoporosis. We recommended sestamibi parathyroid scintigraphy for adequate localization of the adenoma, followed by surgical removal. Based on the DXA score, we decided to initiate antiosteoporotic treatment with denosumab 60 mg 1 injection/6 months and supplementation with 1000 IU vitamin D3.

Conclusions: Although the classical hyperparathyroidism is not frequent nowadays, this diagnosis should be taken into consideration when dealing with osteolytic bone lesions such as osteoclastomas, so that proper treatment could be initiated. In the case we presented above, the late diagnosis of primary hyperparathyroidism led to multiple complications such as ulnar osteoclastoma with pathological fracture and secondary osteoporosis.