Endocrine Abstracts

Case history: An 80-year-old woman, with a background of primary hyperparathyroidism (PHPT), presented to the emergency department with a spontaneous pathological fracture of her left femoral shaft. Blood tests revealed severe hypercalcaemia (corrected calcium 3.26 mmol/l, 2.1 – 2.55) after being lost to follow up for twenty years. She was vitamin D replete after supplementation, had normal renal functions (creatinine 76 umol/L, 50-98), and high parathyroid hormone (PTH 199 pmol/l, 3-12), confirming PHPT. A technetium 99-m-sestamibi scan of her parathyroid gland found intense isotope uptake on right and left sides of her neck. Ultrasound correlation was unclear because of the presence of thyroid nodules. She was medically optimised with Cinacalcet, having initially declined parathyroid surgery.

Investigations: Plain radiography demonstrated a displaced fracture of the proximal left femur through a lucent area. Magnetic resonance imaging revealed abnormal tissue within the bone marrow at the point of fracture and two additional abnormal lesions in the right proximal femur. Computed tomography (CT) of the chest, abdomen and pelvis showed no evidence of underlying malignancy. Whole-body low-dose CT demonstrated multiple, lytic lesions throughout the non-vertebral skeleton; tibiae and femurs, right patella, left radius, right index metacarpals, 2nd and 4th left metacarpals and right 4th middle phalanx. Serum electrophoresis and immunoglobulins were within normal ranges, ruling out myeloma as a diagnosis.

Results and treatment: The patient underwent long gamma nail fixation of the left femur and prophylactic intramedullary nail fixation of both the right femur and left tibia, given the pending fracture risk. She was started on Denosumab (60mg subcutaneously every six months) to reduce osteoclastic activity, and Cinacalcet (60mg orally daily) to reduce serum calcium level while undergoing orthopaedic surgery. Five months following presentation, the patient underwent a right superior and left parathyroidectomy. Histological analysis confirmed parathyroid adenoma of the left inferior parathyroid.

Conclusion and points for discussion: The patient described here had been lost to follow up for almost twenty years and unfortunately presented with uncontrolled PHPT resulting in pathological fracture, and multiple lytic lesions at risk of further fractures requiring significant surgical management. Although extensive bone disease such as this is a rare manifestation of uncontrolled PHPT; it highlights the importance of early parathyroidectomy as the treatment of choice in preventing loss of bone mineral density. Additionally, this case demonstrates that uncontrolled PHPT should be considered in the differential diagnoses of multiple, osteolytic lesions in patients presenting with pathological fractures.