Endocrine Abstracts

Inroduction: Primary hyperparathyroidism most commonly presents with hypercalcemia. Rarely, parathyroid apoplexy or haemorrhage, mimicking a thyroid bleeding cyst is the first presentation of a parathyroid adenoma^(1,3).

Case Report: A 55-year-old woman presented to the ENT department with a sudden onset painful goiter. Ultrasound revealed a sharply defined hypoechogenic nodule in the right thyroid lobe measuring 24.1 x 17.8 x 18.2 mm. The patient was referred to the endocrinology department for fine-needle aspiration (FNA). Repeat ultrasound showed a partially cystic nodule located posterior to rather than in the right thyroid lobe, suggesting parathyroid adenoma bleeding rather than thyroid nodule bleeding. FNA was deferred. Lab testing confirmed hypercalcemia and hyperparathyroidism.^99m Tc-Pertechnetate/SestaMIBI one month after initial presentation showed no uptake in the nodule, which was interpreted as a cold thyroid nodule.¹⁸ F-fluorocholine-PET/CT two months after presentation showed uptake in the nodule, suggestive of a parathyroid adenoma. The patient was referred for parathyroidectomy along with right thyroid lobectomy in case of thyroid adhesion. At surgery, the right inferior parathyroid was strongly fused with the thyroid. A right hemithyroidectomy and resection of the parathyroid adenoma was performed. Pathology showed a parathyroid adenoma, approximately 17 mm in diameter, with an eccentrically located cystic structure (5 mm in diameter), filled with red blood cells and surrounded by a thickened fibrous capsule. The cyst wall contained numerous macrophages with iron pigment deposition.

Conclusion: Diagnostic workup includes dedicated ultrasonography to raise the suspicion of a parathyroid adenoma haemorrhage and to discern it from thyroid nodule haemorrhage. A negative ^99mTc-Pertechnetate/SestaMIBI scan has been reported in most cases of parathyroid apoplexy ^(2,3). Scarce blood supply as well as replacement of metabolically active cells by hemorrhage may contribute to the absence of SestaMIBI uptake. To our knowledge, this is the first parathyroid adenoma apoplexy case in which¹⁸ F-Choline-PET/CT has been performed. In conclusion, cervical pain/haemorrhage along with hypercalcemia point to the diagnosis of parathyroid apoplexy, mimicking a thyroid bleeding cyst. Expedite work-up with ultrasound and if available¹⁸ F-Choline-PET/CT allows for timely surgery, minimizing the risk of recurrent and more severe bleeding. Hence, a two-step process with a localized parathyroid adenoma haemorrhage preceding massive life threatening haemorrhage has been reported⁽⁴⁾.