Endocrine Abstracts

A 75-year-old lady was referred to our centre from a local DGH, where she presented with constipation, reduced consciousness and acute confusion. She was found to have severe hypercalcaemia (Adjusted Calcium 5.21mmol/l), with PTH of 1473ng/l, and urine calcium of 13.8mg/24 h. Based on available biochemistry, a presumptive diagnosis of Parathyroid Carcinoma was made, and Hypercalcemia management was started. She was given about 3 litres of fluid and 60mg of pamidronate. Subsequently, Cinacalcet was created at 30mg BD dose and quickly up-titrated to 90mg QDS due to resistance in decline of calcium levels. There was a worsening of renal function. She was commenced on Renal Replacement therapy to reduce her calcium in preparation for Parathyroid Surgery. She had an NM parathyroid SPECT CT and MIBI, which showed tracer retention in soft tissue in the right paratracheal and retrosternal region, suggesting a parathyroid lesion. The histopathology of the lesion showed a Right inferior parathyroid gland nodule that was finely encapsulated. The lesion was reminiscent of a paraganglioma with abundant finely granular pale staining cytoplasm and no evidence of invasion or necrosis. Despite the paraganglioma-like appearance, the tumour cells were strongly positive for cytokeratin AE1AE3, MNF116 and PTH stains, while the CD56, S100, TTF1 and synaptophysin stains were negative. The Chromogranin stain was weakly positive, and M1B1 stain showed a very low proliferative index. The overall gland architecture was preserved, with surrounding normal parathyroid and adipose tissue. The specimen was labelled as a Parathyroid adenoma, with paraganglioma-like architecture but negative stains. Her post-operative stay was complicated by severe hypocalcaemia, Hospital Acquired Pneumonia and need for ITU stay. She was managed with Intravenous Calcium and Alfacalcidol replacement till her Calcium levels stabilised. This case highlights the treatment challenges of a complex parathyroid adenoma, mimicking a Parathyroid Carcinoma, and the challenging peri-operative Calcium management.