[Parathyroid cyst. Report of ten cases]

Parathyroid cysts: A review of 359 patients reported in the international literature

BACKGROUND

Parathyroid cysts are lesions that represent 1-5% of neck masses. They are subdivided into two categories: functioning and non-functioning.The aim of the present review is to give a detailed account of all reported cases of parathyroid cysts in the literature and to analyze statistically the available data.

METHODS

A bibliographic research was performed from 1905 until 2016. A database with the patients' characteristics was made and analyzed statistically.

RESULTS

A total of 218 articles were found, reporting 359 cases of cysts. Mean age of patients was 49.24 y/o and the male/female ratio was 1:1.85. The most common locations were left thyroid lobe (113/358 patients, 31.6%), and superior mediastinum (69/358 patients, 19.3%), while the most common symptoms were neck mass (148/355 patients, 41.7%), compressive symptoms (73/355 patients, 206%) and hyperparathyroidism (62/355 patients, 17.5%). Non-functioning cysts were more frequent (220/357 patients, 61.6%). Regarding dimensions, mean diameter was 4.88 cm. Ultrasound and FNA are used for their diagnosis, while cystic fluid analysis may help the differential diagnosis. Recurrences were mentioned in 27/97 patients (27.8%) with available data. No deaths due to parathyroid cysts were mentioned in the literature.

CONCLUSION

Parathyroid cysts should be taken into consideration in case of parathyroid dysfunction or asymptomatic neck mass. The surgeon's careful manipulations on the cyst are crucial for a definitive treatment.

Infracentimetric parathyroid cysts in hyperparathyroidemia

Parathyroid cysts are rare, more frequently functional. Here we report 2 cases of infracentimetric parathyroid cysts identified in parathyroid adenomas resected for hyperparathyroidemia and hypercalcemia. Chronic parathyroiditis was associated. Chromogranin and E-cadherin/uvomorulin were expressed heterogeneously in the cyst lining and in parathyroid cells. In one of the cases, CD10 and CD56 were expressed by the luminal membrane of parathyroid cells. CD31 was expressed in interparathyroid cell monocyte/macrophage membrane as well as CD68, several cells showing also CD10 and/or CD56 expression. Ki67 was expressed in sparse parathyroid cells, some of binucleated cells or with nuclear clumps. In conclusion, heterogeneous E-cadherin expression in parathyroid cells may only indirectly related to cyst formation while CD56 and CD10 seem not to relate at all. The relevance of nuclear clumps and Azzopardi phenomenon as well as of the presence of disperse monocyte/macrophage-type cells for the parathyroiditis lesions remains to be further investigated.

Unusual presentations of functional parathyroid cysts: a case series and review of the literature

Background

Cysts of parathyroid origin are sometimes encountered and can easily be mistaken as thyroidal cysts. Functional parathyroid cysts, with symptoms and signs of hyperparathyroidism, are rare and may be a diagnostic challenge to clinicians. We report here on three cases of functional parathyroid cysts that illustrate diagnosis difficulties related to unusual clinical presentations in three Caucasian women, including negative parathyroid scintigraphy.

Case presentations

Patient 1, an 87-year-old Caucasian woman presented with confusion and dysphagia. She had hypercalcemia and elevated parathyroid hormone levels suggesting primary hyperparathyroidism. Parathyroid scintigraphy did not reveal any focal uptake, but a computed tomography scan of her neck identified a large cyst in the upper right thyroid region. At cervicotomy, a parathyroid cystic adenoma was removed. Patient 2, a 31-year-old Caucasian woman was investigated after a hypertensive crisis related to primary hyperparathyroidism. Cervical ultrasound identified a large cystic lesion in the lower left thyroid lobe that was removed by minimally invasive cervicotomy. Patient 3, a 34-year-old Caucasian woman presented with an indolent growing mass of the neck and a past medical history of kidney stones. Primary hyperparathyroidism was diagnosed. Ultrasound showed a cystic mass, but parathyroid scintigraphy was negative. Cervical exploration revealed a large cystic adenoma, containing high parathyroid hormone levels.

Conclusions

Diagnosis of functional parathyroid cysts can be challenging due to various clinical presentations and negative parathyroid scintigraphy. Surgery, but not fine-needle sclerotherapy, appears to be the safest treatment option. Despite its rarity, differential diagnosis of cystic lesion of the neck should include primary hyperparathyroidism due to functional parathyroid cysts.

A single-institution 25-year review of true parathyroid cysts

BACKGROUND

Parathyroid cysts (PCs) are rare, and their origin is a subject of debate. They have been described as either functional, causing hyperparathyroidism, or non-functional in eucalcaemic patients.

PATIENTS AND METHODS

We have performed a 25-year departmental review of PCs. Features studied included the clinical presentation and intra-operative findings, and a histological review was performed. Cases of cystic degeneration of parathyroid adenomas and pseudocystic change were excluded.

RESULTS

Over 25 years, 22,009 thyroidectomies and 2,505 parathyroidectomies were performed in our department. Amongst these, 38 non-functional PCs were documented in 37 patients. The mode of presentation included incidental findings on routine chest x-ray, compressive symptoms or an asymptomatic palpable neck mass. Aspiration was the initial treatment in 14 patients and was curative in 10 of these. Four out of 14 patients underwent surgical procedures for recurrence of the cyst that occurred 6 to 48 months after aspiration. In 27 patients, surgery was performed and all identified PCs were localized in the inferior parathyroid glands. Histologically, the cyst wall consisted in associations of lymphoid, muscular, thymic, salivary, adipose and mesenchymal tissues.

CONCLUSIONS

PCs are rare but should be included within the differential diagnosis of a neck lump. True PCs are non-functional. Pathological and immunohistochemical findings are suggestive of a branchial origin. Fine-needle aspiration may be curative and is diagnostic due to the characteristic appearance of the fluid and high PTH levels on assay.

Intraparathyroid cyst: a tumour of branchial origin and a possible pitfall for targeted parathyroid surgery

BACKGROUND

Parathyroid cysts account for 0.5% of parathyroid pathologies. They usually contain sky-high levels of parathyroid hormone (PTH) but are not necessarily associated with primary hyperparathyroidism (PHPT). Their origin is subject to debate. We provide evidence for a branchial origin and illustrate some potential problems they pose for targeted parathyroid surgery.

METHODS

The present study is a single institution retrospective study of 1702 parathyroid and 10 021 thyroid operations performed over a period of 12 years (1990-2001). Twenty-three cases of parathyroid cyst were found: three palpable neck masses, four cases associated with PHPT and 16 incidental findings at the time of thyroid surgery. Intracystic PTH measurements and immunostaining of the lining wall of the cyst were obtained in 16 out of 23 and 18 out of 23 cases, respectively.

RESULTS

Intracystic PTH levels were elevated in 15 out of 16 cases (average 3877, range 36 000-23 pg\mL). The wall of the cyst stained positively for epithelial cuboidal cell markers (CK +ve) and negatively for PTH (PTH -ve) in 18 out of 18 cases. In only one quarter of the cases associated with PHPT was the cyst the hypersecreting gland, nevertheless it contained less than the average PTH level (1440 vs 3877) and did not take up sestamibi. Results were conflicting in the other three cases. Histological studies on the present series suggest a branchial pouch origin.

CONCLUSION

Despite containing high levels of PTH, parathyroid cysts are of branchial origin and when associated with PHPT are rarely responsible for the disease. Targeted parathyroid surgery should not rely only on ultrasound and intraparathyroid PTH measurements.