Endocrine Abstracts

Introduction: Hypercalcemia is mostly caused by primary hyperparathyroidism and malignancy. Parathyromatosis is a rare condition characterized by multiple nodules of hyperfunctioning parathyroid tissue scattered throughout the neck and superior mediastinum, which can present a diagnostic and therapeutic challenge.

Case report: A 56-year-old woman visited the ER due to chest pain, left-sided neck edema, and hematoma. The day before, she experienced left-sided neck pain and dysphagia. Her other complaints were recent weight loss and fatigue. Due to chest pain and high D-dimer level, CT pulmonary angiography was ordered, which showed a large heterogeneous soft tissue formation extending from the left side of the neck over the upper thoracic aperture and over the posterior mediastinum to just above the esophageal hiatus. The patient was admitted to Respiratory Medicine, where hypercalcemia (serum calcium 3.18 mmol/l; ref. 2.1-2.6 mmol/l) was found. At first, it was thought to be paraneoplastic, and an ultrasound-guided fine-needle aspiration biopsy of the mediastinal formation was performed, which was not diagnostic. FDG PET/CT two weeks after admission revealed a significant shrinkage of the mediastinal formation that showed low metabolic activity. Nothing abnormal was detected elsewhere. Finally, the patient was diagnosed with parathyroid hormone-dependent hypercalcemia (PTH 225 ng/l; ref. 10-65 ng/l) and transferred to Endocrinology. After parenteral hydration and introduction of a calcimimetic, serum calcium level fell to 2.68 mmol/l. Marked hypercalciuria (17 mmol (680 mg)/24 h was found, however, nephrocalcinosis or nephrolithiasis on ultrasound were absent. Bone mineral density was in the range of osteoporosis (T-scores: lumbar spine -2.5 SD, femoral neck -2.6 SD, one-third radius -4.5 SD) with increased bone turnover (bone-specific ALP 59.1 μg/l; ref. 5.5-27.1 μg/l, CTX 3.976 μg/l; ref. 0.142-1.351 μg/l, PINP 50.0 μg/l; ref. 27.7 – 127.6 μg/l). 18F-choline PET/CT showed hyperfunctioning parathyroid tissue at the lower part and behind the left thyroid lobe. A metabolically active process around the esophagus extending caudally to Th3 level was also present. Surgery revealed extensive parathyromatosis at the lower part of the left thyroid lobe and in the neck adipose tissue. Histopathology confirmed extensive parathyromatosis. A surgical cure was not possible, and the patient continued treatment of persistent primary hyperparathyroidism with a calcimimetic. Cholecalciferol supplementation and zoledronate were given for osteoporosis.

Conclusion: We present a patient with mediastinal mass and hypercalcemia, which was first thought to be paraneoplastic. Further diagnostic workup revealed a rare case of spontaneous rupture and hemorrhage of a parathyroid adenoma with subsequent surgically incurable parathyromatosis.