Incidentally discovered severe hypercalcaemia from a functioning parathyroid cyst: the limitations of intraoperative parathyroid hormone (IOPTH) monitoring

Parathyroid cysts (PCs) are rare pathologies and are typically non-functional (do not secrete parathyroid hormone (PTH)). The aetiology of PCs is highly debated, and management is complex. We present a unique case of a parathyroid adenoma contained within a functional PC and highlight the limitations of intraoperative PTH monitoring during the surgical resection of functional PCs.

Parathyroid cyst: A rare entity

Parathyroid cysts are an uncommon entity. They are classified as functioning and nonfunctioning cysts. Cyst aspiration with detection of parathyroid hormone is a useful tool to confirm the diagnosis. Here, we report four cases of parathyroid cysts. One patient had a functioning cyst. Ultrasonography of the neck revealed a cystic lesion behind the left lobe of the thyroid gland in two cases and a right cystic thyroid nodule in two cases. The cysts exerted a mass effect on the adjacent structures in two cases without clinical compressive symptoms. Fine-needle aspiration with detection of parathyroid hormone in the cyst fluid was performed in one case (nonfunctioning cyst): intracystic parathyroid hormone level was high. Recurrence was noted 1 month after the cyst aspiration. All patients underwent surgical treatment. Our series is characterized by two cases of nonfunctioning intrathyroidal parathyroid cysts which are very uncommon. They are mistaken for thyroid cysts. After surgery, no recurrence was noted. We aim to describe the epidemiological, clinical, and paraclinical features of this condition as well as its therapeutic modalities.

Parathyroid cyst: differential diagnosis

Parathyroid cysts are rare lesions of the cervical region and less frequently of the mediastinum. They occur mostly in women and are usually asymptomatic. They generally occur in the fourth and fifth decades of life and mainly are non-functioning. They commonly present as a neck mass that is found incidentally during surgery or in imaging test. Its importance lies in the difficulty in diagnosis, often confusing itself with thyroid pathology. The diagnosis is usually made intraoperatively, confirmed by histopathological examination.The aim of this paper is to report a case of parathyroid cyst that mimics a thyroid nodule.

Fine-needle aspiration washout in the diagnosis of cystic parathyroid adenoma

Cystic parathyroid adenomas are one of the rare causes of neck masses. Due to its rarity, it causes misdiagnosis and wrong treatments and has undesirable consequences. The measurement of parathyroid hormone in fine-needle aspiration washout fluid is a minimally invasive, safe method for the diagnosis of parathyroid cysts and seems to be more useful than Tc-99m sestamibi (MIBI) parathyroid single photon emission computed tomography (SPECT)/CT.