Parathyroid FNA and hormone assay.

Primary hyperparathyroidism is a relatively common problem encountered in clinical endocrine practice. In most cases the diagnosis is relatively straightforward, however, when imaging studies fail to localize the parathyroid adenoma or hyperplasia, management can be challenging. We describe here such a case where the diagnosis was made by a novel method of analysis of parathyroid hormone levels in the needle wash obtained during fine-needle aspiration of a suspected parathyroid adenoma. A 60 year old white male was first seen in the endocrinology clinic for evaluation of osteoporosis. He had history of multiple compression vertebral fractures involving thoracic and lumbar vertebrae and fracture of right femoral neck following minimal trauma. He had high normal serum calcium and elevated urinary calcium levels. His parathyroid hormone level was within normal limits. Work-up for secondary causes of osteoporosis was unremarkable. He was started on hydrochlorthiazide therapy for a presumptive diagnosis of idiopathic hypercalciuria. Subsequently his serum calcium level became elevated and he continued to have significant hypercalciuria. The elevation in serum calcium persisted despite cessation of hydrochlorthiazide therapy. Parathyroid hormone level remained in mid-normal range. A diagnosis of primary hyperparathyroidism was considered at this stage and imaging studies were carried out to localize the parathyroid pathology. Parathyroid-sestamibi scan did not reveal any abnormality. Ultrasound examination of the neck showed a hypoechoic nodule posterior to right thyroid lobe. A fine needle aspiration of the nodule was carried out with estimation of parathyroid hormone level in the needle wash to indicate the presence of parathyroid adenoma. This was surgically removed later successfully with subsequent normalization of serum and urinary calcium levels. The current management of hyperparathyroidism is primarily surgical. Minimally invasive parathyroid surgery is the treatment of choice but it requires the clear localization of a parathyroid lesion for successful removal. In cases where preoperative localization is evasive, novel techniques, such as the one described above, can provide useful diagnostic information which can aid in the successful management of hyperparathyroidism. Further studies are needed before this technique can be applied on a more widespread basis.