Endocrine Abstracts

Sixteen percent of parathyroid adenomas can be situated in an ectopic location. Ectopic parathyroid glands result from aberrant migration during early stages of development, and lack of successful identification may lead to lack of success in parathyroid surgery. These glands are most frequently found in the anterior mediastinum, in association with the thymus or the thyroid gland. Ectopic parathyroid glands are a major cause of persistent and recurrent hyperparathyroidism.

The aim of the study was presented to patients with persistent primary hyperparathyroidism due to ectopic parathyroid adenoma in the chest.

Case report: This is a 67–year–old woman who was presented with fatigue and was diagnosed with primary hyperparathyroidism two years ago. At the time of diagnosis, the patient had the following findings: high levels of parathyroid hormone (PTH), ionized calcium and easily reduced phosphate values. Technetium-99m–sestamibi (MIBI) scintigraphy scan was positive and detected enlarged and hyperactive upper right parathyroid gland. The ultrasound showed a multinodally enlarged thyroid gland. The patient was referred to a surgeon. The parathyroid hormone and ionized calcium levels were not normalized postoperatively. The repeated Technetium-99m-sestamibi (MIBI) scintigraphy showed this time an enlarged and hyperactive lower left parathyroid gland. After that, an exploitative cervicotomy was done but the parathyroid glands could not be enlarged in the expected projects. Even after repeated operations there was again an elevated PTH level, elevatedionized and total calcium levels with normal calciuria. The patient was again advised to do parathyroid gland scintigraphy. The third scintigraphy detected localized parathyroid adenoma/hyperplasia in superior mediastinum (an enlarged and hyperactive parathyroid gland ectopically localized behind the upper part of the left half of the sternum manubrium).The computed tomography of the chest and lower neck showed an ovoid soft tissue density area measuring about 21 × 18 × 13 mm in the superior mediastinum. The patient was again referred to the surgeon. The removal of the lesion resulted in rapid improvement in serum calcium and parathyroid hormone.

Conclusion: In addition to the enlarged and hyp\eractive parathyroid glands at the typical site of the neck, the development of ectopically located parathyroid glands is also possible. Therefore, we think that the attention should be paid to this in dailyclinical practice. The neck ultrasound and 99mTc Sestamibi scan are first–line imaging modalities, although with low sensitivity and specificity. However, their combination with modern techniques, such as single photon emission computed tomography (SPECT) alone or in combination with CT (SPECT/CT) increases their diagnostic accuracy.