Parathyroid cysts: experience of a rare phenomenon at a single institution

Abstract

Background: Parathyroid cysts are relatively uncommon lesions and are often misdiagnosed. We evaluate our experience in the diagnosis of and therapy to correct parathyroid cystic lesions.

Methods: We retrospectively reviewed a series of 32 patients with parathyroid cysts who were admitted to our department between July 2011 and November 2016. Clinical pathological features of the patients, including age, gender, location, size, ultrasonography, histopathology, surgery, and follow-up, were analyzed.

Results: There were 22 female and 10 male participants with a median age of 46.7 years old (27-76 years old). Only two cysts were found in the superior mediastinum. The rest were located under the lower pole of the thyroid. All of the patients underwent ultrasonography scans and serum parathyroid hormone (PTH) assays. Three patients had elevated serum PTH levels, and they were further scanned with Tc99m sestamibi as functional cysts. In 29 cases of nonfunctional cysts, 3 cases were preoperatively diagnosed by cystic aspiration with PTH detection. The rest were diagnosed by postoperative immunopathology. All of the patients underwent cystectomy, and 24 patients also underwent thyroidectomy. There was a significant difference in cyst diameter size between the cystectomy alone and cystectomy with thyroidectomy groups (4.0 ± 2.0 vs 1.5 ± 1.0 cm; p < 0.05). No participant experienced recurrence during the median 36 months of follow-up.

Conclusions: Cystic lesions located under the lower pole of the thyroid gland should be considered to have originated at the parathyroid gland. Cystic aspiration with PTH detection or postoperative immunopathology can lead to a definitive diagnosis. Cystectomy is still a commonly used and effective treatment.

Keywords: Cystectomy; Parathyroid cyst; Parathyroid hormone; Thyroidectomy.

Fig. 1

Representative case with enhanced computer tomography scan showing a huge cyst in the superior mediastinum. Cystic lesion (4×3 cm); PC, parathyroid cyst

Fig. 2

Representative case with PC ultrasonography scans. Cystic lesion (2.5×2×0.8 cm) in right lobe of thyroid gland. PC, parathyroid cyst

Fig. 3

Representative case with immunopathology of parathyroid cysts. Cytoplasmically stained blown cells with antibody against PTH are parathyroid cells (arrow); cyst lumen (black asterisk) (40×)

Fig. 4

Representative parathyroid cysts as seen intra-operatively. PC, parathyroid cyst

Fig. 5

Process for evaluation and management of patients with suspected parathyroid cyst. PTH, parathyroid hormone; Tg, thyroglubin