Cysts of the parathyroid glands. Apropos of 6 cases

Parathyroid cysts are rare lesions. Pathological examination distinguishes the "true" parathyroid cysts (non functional) most often present and cystic degeneration of a parathyroid adenoma (rare) with clinical or biochemical evidence of hyperparathyroidism. With the increased use of ultrasound and fine needle aspiration biopsies, the diagnosis of these cysts can be confirmed by an elevated parathyroid hormone (PTH) assay. The non-functioning parathyroid cysts can be successfully treated by total aspiration of the cyst fluid. Surgical exploration of all parathyroid glands is the treatment of choice for hyperparathyroidism. The different proposed etiologies for parathyroid cysts are discussed.     

Parathyroid cysts

Cystic neck masses may be accurately diagnosed by sonography, and some nonfunctioning parathyroid cysts can be cured by percutaneous aspiration. Primary hyperparathyroidism should be considered in all patients with cystic neck masses. Parathyroid cysts can often be recognized from the characteristics of the cyst fluid which is usually clear and colorless, contains elevated parathyroid hormone levels and normal or low thyroid hormone levels, and may contain parathyroid cells. Parathyroid cysts may be multiple; all four parathyroid glands should therefore be identified and appropriately removed or hyperparathyroidism may persist.     

Needle aspiration of nonfunctioning parathyroid cysts

Until recently, nonfunctioning parathyroid cysts were usually identified at operation for a presumed thyroid mass. Thyroid needle biopsy now allows their preoperative diagnosis and potential definitive treatment. This study reviews four patients with nonfunctioning parathyroid cysts treated during a two-year period. Three women and one man range in age from 28 to 70 years. Each presented with an asymptomatic thyroid mass ranging from 3 to 5 cm in length. None had symptoms of primary hyperparathyroidism. Serum calciums were from 9.2 to 10.7 mg/dl and serum phosphoruses were 3.2 to 4.4 mg/dl. Needle aspiration revealed 5 to 85 cc of water-clear fluid. C-terminal parathyroid hormone in three patients was 12,600, 6,500 and 61,200 pg/ml and N-terminal PTH was 1,700 pg/ml in one. All four had normal serum calcium and phosphorus on follow-up ranging from six months to two years. Two patients had resolution of their cysts with a single aspiration. One patient had recurrence but has no evidence of recurrence six months after injection with tetracycline. Another patient had a recurrence but remains well one year following reaspiration. Nonfunctioning parathyroid cysts present as a thyroid mass. Needle aspiration of water-clear fluid high in parathormone is diagnostic and, in most patients, is the therapeutic modality of choice.     

Treatment of a nonfunctioning parathyroid cyst with tetracycline injection

Parathyroid cysts are uncommon: about 200 cases have been reported. They can be functional (i.e., accompanied by signs of primary hyperparathyroidism), or nonfunctional. Preoperative diagnosis is difficult, although it has become increasingly frequent with the use of ultrasound and fine-needle aspiration biopsy. Fluid of parathyroid cysts is almost invariably watery, colorless, and crystal clear, which should cause clinical suspicion. However, definitive diagnosis relies on the demonstration of high parathyroid hormone (PTH) levels in the fluid. Puncture may cure nonfunctioning cysts, but surgery is indicated when the lesion recurs after several fine-needle aspirations. We report a case of a nonfunctioning parathyroid cyst in a 17-year-old boy, which reappeared after two punctures made 6 months apart. On the third occasion, 1 mL of a sterile tetracycline solution injected into the cyst cured the lesion. Tetracycline and other sclerosants have been recommended as a treatment of recurring thyroid cysts. We suggest that injection of a sclerosant should be considered as an alternative to surgery in recurring, nonfunctional cysts of the parathyroid glands.     

Parathyroid Cyst: Often Mistaken for a Thyroid Cyst

Introduction Parathyroid cysts are rare but clinically significant lesions. They can be functional, mistaken for a thyroid cyst, and/or managed nonoperatively on occasion. Methods We identified seven patients (1 male, 6 females) with the diagnosis of parathyroid cyst from 1998 to 2003. Results Altogether, 33% of the patients had functional cysts. Sestamibi scans were performed in three of the seven patients, including two with functional cysts; none showed focal uptake. In toto, six of the seven cysts (86%) were found in an inferior parathyroid gland. All of the cysts had crystal-clear aspirate. C-terminal parathormone (PTH) levels were obtained from the aspirate from five of the seven (71%) patients. The mean level was 269,736 pg/ml (1970–1,268,074 pg/ml). Surgery was performed in three of the seven (43%) patients. All patients who underwent surgery improved postoperatively based on symptoms and serum levels of calcium and PTH. The four patients (57%) who were treated nonoperatively were subjected to aspiration alone; three (75%) of those patients required multiple aspirations. Conclusions Most parathyroid cysts are nonfunctional and are rarely symptomatic. They are usually located in an inferior gland. If aspirated, most of the cysts reaccumulate fluid. Operative management is usually straightforward and alleviates symptoms and any biochemical abnormalities caused by the cyst. This study was presented as a poster at the meeting of the American Thyroid Association, Vancouver, BC, October 2004     

Parathyroid cysts of the neck and mediastinum. Case report

Five cases of parathyroid cyst are presented and the literature concerning this rare entity is reviewed. Three of the five cysts were located in the neck and were non-functioning. The other two were in the anterior mediastinum and functioning, and indeed were associated with hypercalcemic crisis. Four cases were treated surgically, and in one non-functioning parathyroid cyst both diagnosis and treatment were accomplished with fine-needle aspiration. The cystic appearance, color of the fluid contents, high content of parathyroid hormone and histologic features distinguish parathyroid cyst from the much commoner thyroid cyst. Non-functioning parathyroid cysts can be treated with fine-needle aspiration, whereas functioning cysts require surgical removal.     

Parathyroid cysts

Fourteen new cases of parathyroid cyst are presented. Two distinct groups were identified: functioning and nonfunctioning. Patients with functioning cysts presented with hypercalcemia, tended to be men and were older. Patients with nonfunctioning cysts were all women, had normocalcemia and all presented with neck masses. Ultrasonography proved useful while radionuclide thyroid scans were often misleading. In the functioning group removal of parathyroid cysts resulted in postoperative normocalcemia in all cases. In the nonfunctioning cysts thyroid lobectomy was performed in five of six instances. Parathyroid cysts usually contain clear or serous fluid and are surrounded by a well-delineated plane of dissection. We believe that preoperative aspiration of cystic neck masses and consideration of the diagnosis of parathyroid cysts may avoid needless thyroid lobectomy.     

Parathyroid cysts]

The Authors review the world literature on parathyroid cysts and report a case of this uncommon disease. The importance of an early pre-operative diagnosis by ultrasound, blood calcium level and parathyroid hormone assay with fine needle aspiration biopsy is pointed out. According to several surgeons, only the functioning parathyroid cysts require operation; needle aspiration may be appropriate therapy for the nonfunctioning ones.     

无功能性甲状旁腺囊肿：附15例报告

目的 了解无功能性甲状旁腺囊肿的临床特点,探讨其诊治方法.方法 对近16年来收治的无功能性甲状旁腺囊肿15例患者的临床资料进行回顾性分析研究.结果 术前均未获得诊断,均经术后病理检查证实.全组均行手术切除获得治愈,随访无复发.结论 对无功能性甲状旁腺囊肿,病理学检查是最可靠的诊断方法,针刺抽液测定PTH或细胞学检查有助于术前诊断.手术切除是最理想的治疗方法.     

A giant nonfunctioning parathyroid cyst

Summary A case of a giant nonfunctioning parathyroid cyst is presented. The diagnosis was missed preoperatively, due to unfamiliarity with this pathology. Functioning parathyroid cysts cause hyperparathyroidism and are easy to diagnose. Nonfunctioning parathyroid cysts produce only a mass in the neck, without other symptoms. From the literature it appears that they are seldom diagnosed preoperatively. However, aspiration of clear, colorless watery fluid should lead to a correct diagnosis. This case is interesting because of its rarity and of the giant size of the cyst. No evidence of a parathyroid cyst of these dimensions has been found in the literature. This case also proves that parathyroid cysts may recur after aspiration; thus aspiration is not always the definite treatment of these cysts.Paper presented at the Autumn Meeting of the Belgian Society for Plastic, Reconstructive and Esthetic Surgery, Leuven, Belgium, November 4, 1989 Offprint requests to: Prof. G. Matton     

Mediastinal parathyroid cyst with tracheal constriction

A 63-year-old man visiting a physician for slight dyspnea, attributed to a lump on his neck, was found in ultrasonography and computed tomography to have a cyst extending from the left lobe of the thyroid gland to the superior mediastinum. Radiography showed right deviation of the trachea. The cyst disappeared after fine-needle aspiration, but cyst fluid subsequently reaccumulated and he was admitted to our hospital. No abnormalities were detected in tests of thyroid and parathyroid function or blood chemical analysis. The cyst was surgically removed and diagnosed as a nonfunctioning parathyroid cyst, based on the high-intact parathyroid hormone in cyst fluid. The patient recovered fully and has shown no recurrence in the 11 months to data since surgery.     

Mediastinal parathyroid cyst with tracheal constriction.

A 63-year-old man visiting a physician for slight dyspnea, attributed to a lump on his neck, was found in ultrasonography and computed tomography to have a cyst extending from the left lobe of the thyroid gland to the superior mediastinum. Radiography showed right deviation of the trachea. The cyst disappeared after fine-needle aspiration, but cyst fluid subsequently reaccumulated and he was admitted to our hospital. No abnormalities were detected in tests of thyroid and parathyroid function or blood chemical analysis. The cyst was surgically removed and diagnosed as a nonfunctioning parathyroid cyst, based on the high-intact parathyroid hormone in cyst fluid. The patient recovered fully and has shown no recurrence in the 11 months to data since surgery.     

Fine needle aspiration of neck tumor. Application of cytological, bacteriological and hormonal examinations

Aspiration of neck tumors with a fine needle combined with cytological, bacteriological and hormonal examinations greatly improved the accuracy of the differential diagnosis of the neck tumors. Fine needle aspiration cytology in 45 patients with thyroid tumor gave only 4% (1/25) false negative diagnosis and 0% (0/20) false positive diagnosis for carcinoma, whereas false negative and false positive diagnosis by palpation were 34% and 4%, respectively and those by soft tissue roentgenogram were 55% and 0%, respectively. Differential diagnosis of histological types of thyroid carcinoma was possible by cytology. Fine needle aspiration of cervical lymph nodes gave the diagnosis of malignant lymphoma, metastatic squamous cell carcinoma, adenocarcinoma or inflammatory changes. Bacterial culture from the aspirate yielded causative microorganism in 5 patients including 4 with tuberculosis. The specimens aspirated from thyroglossal duct cysts or branchial cysts showed specific appearance and cytological feature. The aspirate from a parathyroid cyst was watery clear and contained high amount of parathyroid hormone. Dark brown serous aspirate from extrathyroidal mass suggested metastatic lesion from occult papillary carcinoma of the thyroid in 2 patients. Demonstration of very high content of thyroglobulin of the aspirate determined by radioimmunoassay supported the diagnosis, which was confirmed later at surgery. This method has become a routine work in our out-patient clinic.     

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.     

Parathyroid cyst: diagnosis and treatment of an unusual surgical problem

A case of parathyroid cyst is reported in which the diagnosis was suggested when watery, clear fluid was aspirated from a mass found in the anterior region of the neck of a 34-year-old woman on routine medical examination. The diagnosis was confirmed by measurement of the parathormone content in the cyst fluid and by histologic examination of the cyst wall. Although rare, parathyroid cyst should be considered in the differential diagnosis of cysts in the anterior compartment of the neck. Surgery has been the usual treatment of such cysts, but several reports have been published in which repeated aspiration resulted in the disappearance of the cyst. If conservative treatment of a parathyroid cyst is unsuccessful, the cyst should be removed surgically.     

Parathyroid cysts: reprot of 2 cases and review of the literature

Although parathyroid cysts are rarely described in the literature, they should be considered in the differential diagnosis of cysts occurring in the anterior compartment of the neck. We report two cases. The presence of elevated parahormone in the clear fluid aspirate is the diagnostic criterion. Parathyroid cysts may be functional, probably resulting from cystic formation of a parathyroid adenoma, or non function with their own epithelial lining, probably arising from remnants of the pharyngeal pouch or Kursteiner's canal. Search for both hypercalcemia and hypophosphoremia are needed. Fine needle aspiration provides the diagnosis and is also the treatment of choice for non-functional parathyroid cysts. Aspiration of functional cysts can reduce the hormone level to normal prior to surgical removal.     

Analysis of parathyroid hormone in bovine parathyroid cysts

Parathyroid cysts were found in 2-5% of beef steers and heifers while collecting parathyroids at a local abattoir. The cyst fluid contained parathyroid hormone (PTH), averaging 15 ng/ml of fluid. Reversed-phase high-performance liquid chromatographic (HPLC) analysis of the fluid using an acetonitrile-trifluoroacetic acid solvent system, followed by carboxyl-terminal specific PTH radioimmunoassay of the eluant fractions, revealed two major peaks of PTH immunoreactivity. The first eluted at approximately 25% acetonitrile, a position similar to the commercially available human carboxyl terminal fragment of PTH-(39-84). The second peak, at approximately 37% acetonitrile, corresponded to the elution position for bovine PTH-(1-84). The cyst fluid was tested for enzyme activity by incubation of 125I-labeled bovine PTH with cyst fluid for 30 minutes at 37 degrees C, which resulted in no fragmentation of the labeled peptide. Immunohistochemistry of the cells lining the parathyroid cyst indicated that they contained PTH.     

Pathologic nature of cystic thyroid nodules selected for surgery by needle aspiration biopsy

Sixty euthyroid patients with cystic hypofunctioning thyroid nodules were selected for operation by the criteria of evidence of needle aspiration of cyst fluid with malignant cytologic findings, suspicion of malignancy on the basis of recurrent cyst fluid formation after at least two aspirations, or incomplete decompression after aspiration. Other factors such as size (greater than 3 cm in diameter), history of radiation, and cervical lymphadenopathy were given weight. Radiation exposure occurred in 14% of patients. Surgical pathologic findings revealed malignancy in 32%, adenoma in 43%, and colloid nodule in 25%, with a total neoplasia rate of 75%. The types of malignant tumors included six papillary, six mixed, three follicular, and four Hurthle. Surgical treatment included 26 near total thyroidectomies, 34 partial thyroidectomies, and four neck dissections without major morbidity or deaths. Cytologic false-negative rates were 50% cancer, 50% Hurthle cell 50%, and 60% adenoma, even after nucleopore filtration, emphasizing the value of surgical selection on the basis of cyst response to aspiration. Cytologic false-positive rate in the colloid group was 6% and 25% for false (solid) positive for echography. Bloody fluid occurred in all types of lesions but was more common in the cancer group. Thyroid ultrasonography does not appear to be an important way to assess thyroid nodular disease and has been, in our estimation, superseded by needle aspiration cytology. It should be recognized that cystic thyroid nodules, when selected for operation on the basis of the above mentioned needle biopsy and clinical criteria, have the same frequency of neoplasia and cancer as solid hypofunctioning thyroid nodules. Hence, it is recommended that all cystic lesions of the thyroid gland be assessed in accordance with such criteria to exclude underlying cancer.     

Parathyroid cyst of the thymus.

A case is described of primary hyperparathyroidism in a patient with both a parathyroid cyst within the thymus gland and a concomitant parathyroid adenoma. The parathyroid adenoma contained microcystic areas of degeneration, and it is thought that the parathyroid cyst reflected degenerative change in a pre-existing adenoma. Parathyroid cyst should be considered in the differential diagnosis of cystic lesions within the thymus. Fine needle aspiration and parathyroid hormone assay on cyst fluid may provide a preoperative diagnosis.     

Percutaneous tetracycline instillation for sclerosis of recurrent thyroid cysts

Of 770 hypofunctioning thyroid nodules subjected to needle biopsy since 1977, the fluid of 172 cysts (22%) was aspirated. The fluid, cytologically examined, showed no evidence of carcinoma except in three instances: papillary carcinomas that were subsequently treated surgically. Of the cystic lesions, 19 (11%) recurred and were treated by reaspiration and the instillation of tetracycline hydrochloride into the cyst cavity. In all but one instance this resulted in obliteration of the cysts (95%). This is a considerably higher rate of success than that reported from aspiration alone (40% to 85%). The follow-up period ranged from 1 to 42 months, with no recurrence or subsequent development of a thyroid nodule in these patients. The one recurrent cyst was reaspirated and reinstilled a second time, which resulted in great reduction in size. Not considered for this procedure were patients in whom the cytologic condition of the fluid was abnormal or indicative of a malignancy. Also excluded were those in whom there was incomplete decompression of the cyst, manifested by a persistent nodule. No patients had a history of head or neck irradiation or cervical lymphadenopathy, both contraindications for this procedure. No patients had grossly bloody aspirates. Recurrence of thyroid cysts after aspiration was not thought to be, in itself, a criterion for surgical selection. The effective use of tetracycline hydrochloride as a sclerosing agent in the treatment of malignant pleural effusions is well documented. Its action in producing symphysis is thought to be related to its low pH (2.0). This procedure is safe, simple, cost effective, and well tolerated by patients. It obviates the need for excision in patients who fulfill the aforementioned criteria.