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

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.     

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.     

Recurrent hyperparathyroidism due to implantation of parathyroid tissue

Recurrence of hyperparathyroidism after initially successful primary operation is usually caused by inadequate resection of diseased tissue or recurrent carcinoma. Since it is known that normal parathyroid tissue may be autotransplanted into a muscle bed, it is plausible that inadvertent implantation of parathyroid tissue spilled at operation may occur. In four of 23 reoperations for hyperparathyroidism in an 11 year period, we found evidence that iatrogenic parathyroid implantation had occurred. Two of the four patients had multiple parathyroid implants in the previous operative field, and one of these patients had documented spillage of a cystic adenoma during the original operation. Another two of the four patients were found to have recurrent adenomas containing suture material at sites of previous excision of the adenomas. No patient had gross or histologic evidence of parathyroid carcinoma. We conclude that inadvertently spilled parathyroid tissue may implant in the neck or mediastinum and cause persistent or recurrent hypercalcemia. Therefore, all efforts should be made to handle the parathyroid glands only by their pedicles and not to crush, suture, or violate the capsule. Needle aspiration of parathyroid cysts could lead to implantation along the needle tract.     

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.     

Hyperparathyroidism due to primary cystic parathyroid hyperplasia

Cysts of the parathyroid glands are uncommon, and functioning parathyroid cysts that cause primary hyperparathyroidism are rare. A 63-year-old man had primary hyperparathyroidism because of cystic hyperplasia of all four parathyroid glands. He also had squamous cell carcinoma of the soft palate, chronic renal failure, hypertension, type-4 renal tubular acidosis, a hyperplastic thyroid adenoma, and hyporeninemic hypoaldosteronism. To our knowledge, this is the first patient to be described with hyperparathyroidism due to multiple parathyroid cysts. The finding of cystic involvement of all four glands supports the theory that at least some parathyroid cysts are either a result of a common embryologic defect or of retention of parathyoid secretions rather than of cystic infarction of parathyroid adenomas.     

Two cases of hyperfunctioning parathyroid cyst

Two cases of parathyroid cyst were experienced. Both cases presented clinical data and symptoms of hyperparathyroidism. Microscopically, one had a thin fibrous wall containing parathyroid adenomatous tissue in the inner surface and the other showed cyst formation without any histological evidence of adenoma or hyperplasia. Most parathyroid cysts are non-functioning. In occasional cases, the cyst may contain a hyperfunctioning adenoma. The hyperfunctioning parathyroid cysts with normal parathyroid tissue are discussed.     

Needle aspiration of nonfunctioning parathyroid cysts

Parathyroid cysts, appearing as thyroid masses, have been previously diagnosed at operation or by permanent histologic specimens. With the advent of ultrasound and fine-needle biopsies, these very rare cysts can now be diagnosed by needle aspiration. The pearly clear fluid of a parathyroid cyst contrasts with the sanguineous or even chocolate-brown fluid of a thyroid cyst. The high parathyroid hormone (PTH) level of the fluid confirms the diagnosis, and a blood calcium level determines its function or nonfunction in the patients. Of our seven nonfunctioning parathyroid cysts, the first three were diagnosed by operation and the other four by needle aspirations. The PTH determination ranged from 20,000 to 42,000 pg/mL. We suggest that needle aspiration, rather than operation, be the treatment of choice.     

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.     

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     

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.     

Recurrent nerve palsy due to parathyroid cyst

Cysts of the parathyroid gland are uncommon neck masses and difficult to diagnose. They can cause symptoms by endocrinological function or by pressure on surrounding structures. A case of recurrent nerve palsy due to a parathyroid cyst is presented. Aspiration of parathyroid cysts can be diagnostic and therapeutic in some cases.     

Thoracoscopic resection of a giant mediastinal parathyroid cyst

Parathyroid cysts are a rare situation, unusually in the mediastinum. The preoperative diagnosis could be more difficult in some atypical topographies and imaging characteristics in particular in case of huge mediastinal cyst. In the following years traditionally, in case of intrathoracic parathyroid cysts, sternotomy or thoracotomy have been the preferred approaches. We report a case of an older patient with a huge mediastinal parathyroid cyst removed successfully using videothoracoscopy.     

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.     

Salivary heterotopia, cysts, and the parathyroid gland: branchial pouch derivatives and remnants

Five cases of periparathyroid salivary heterotopia associated with cysts were studied. The specimens were obtained from three men and two women age 36 to 62 years who underwent surgery for primary hyperparathyroidism (four patients) and thyroid nodule (one patient). The heterotopia-cyst combination occurred with normal and abnormal parathyroid glands (four inferior and one of unknown location). Review of histologic slides of all parathyroid glands excised from 258 patients during a 1-year period at the Mayo Clinic revealed two similar salivary gland-cyst units. Seven more cases featured one or more periparathyroid cysts, five with other nonsalivary-type epithelial accompaniments. One of the latter additionally had a focus of parathyroid cells in the cyst wall, and associated thyroid parenchyma with C cells, and cartilage.     

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 cytology: avoiding diagnostic pitfalls

BACKGROUND: Interpretation of parathyroid fine-needle aspirates (FNA) remains problematic not only because this type of specimen is rare but also because the pertinent literature is very limited. We systematically reviewed parathyroid FNAs in our files and sought to delineate additional diagnostic criteria. DESIGN: Review of all thyroid and parathyroid aspirates from January 1990 to June 1998 disclosed 12 parathyroid lesions. The final diagnoses included four parathyroid adenomas, one intrathyroidal hyperplastic parathyroid, one intrathyroidal parathyroid adenoma, one atypical parathyroid adenoma (all confirmed by histologic screening or immunocytochemistry), and five parathyroid cysts (all confirmed by immunoassay). Papanicolaou and Diff Quik-stained smears of the parathyroid FNAs were reviewed. The cytologic features were compared and contrasted with those of thyroid FNAs to establish criteria for differential diagnoses. RESULTS: The FNAs of the five parathyroid cysts yielded virtually acellular fluid with a characteristic water-clear appearance and markedly elevated levels of parathyroid hormone. The remaining seven aspirates consisted of moderately cellular smears that showed an admixture of architectural features. Common patterns included cohesive three-dimensional groups, disorganized sheets, papillary fragments, microfollicles, and a single case showing lymphoidlike smears. Although the cells were generally small and round to oval, all cases demonstrated mild to moderate anisokaryosis. The nuclei were hyperchromatic E with coarsely granular chromatin reminiscent of that of small lymphocytes. Occasional nucleoli were noted. Although the cytoplasm was usually pale blue and finely granular with ill-defined borders, two cases showed well-delineated cytoplasmic membranes. Less common findings included cytoplasmic granulation, vacuolization, and rare oxyphilic cells. Naked nuclei were noted in the background of all of the aspirates to varying degrees. Other background findings included the presence of colloidlike material, macrophages, and lymphocytes. One interesting finding that to date has not been reported is the presence of nuclear overlapping (100%) and nuclear molding (71%), which is an uncommon finding in thyroid aspirates. CONCLUSIONS: FNAs of the parathyroid can be easily confused with that of the thyroid, not only because of the clinical similarity between these two types of lesions but also because of the overlap in cytomorphologic features of the aspirated cells. Although no one single cytomorphologic feature is diagnostic, a combination of cytologic parameters noted earlier should raise the possibility of a parathyroid lesion. Aspirates of parathyroid cysts show acellular water-clear fluid with elevated parathyroid hormone measurements.     

Giant functioning parathyroid cyst presenting as a retrosternal goitre

Parathyroid cysts are rare and even more rarely cause a neck mass resembling a goitre. Such large parathyroid cysts may involve the mediastinum, growing to a sufficient size to produce symptoms related to obstruction, and if functioning, primary hyperparathyroidism. Parathyroid cysts should be considered in the list of differential diagnoses of anterior neck masses to allow for appropriate preoperative investigation to avoid unnecessary confusion at the time of operation. We report a case where a functioning parathyroid cyst presented as a retrosternal goitre to emphasize the potential pitfalls associated with their diagnosis and management.     

Mediastinal parathyroid cysts revisited

BACKGROUND: A case of a functioning mediastinal cyst is presented. METHODS: A comprehensive review of the literature found 93 patients in whom a parathyroid cyst or cysts extended into, or was completely contained within, the mediastinum. Including our patient, there were 46 men and 45 women, and the gender was not recorded in three. RESULTS: The cysts were located in the anterosuperior region in 56 patients, in the middle region of the mediastinum in 26, and in the anterior, prevascular region in 12. Thirty-nine patients had functioning cysts associated with hyperparathyroidism of varying severity; seven patients presented with a hypercalcemic crisis. Local symptomatology consisted of a neck mass, respiratory distress, and occasional dysphagia or chest pain. Recurrent laryngeal nerve paresis was present in nine patients, and innominate vein compression or thrombosis was present in two. The cysts in all but four patients were treated by open surgical excision; two were treated by thoracoscopy, and two patients only had fine-needle aspiration of the cyst. The cyst was excised via a cervical approach in 67 patients and by a thoracotomy or median sternotomy or a variation thereof in 23. There was no operative mortality and morbidity was minimal. CONCLUSION: Surgical resection was successful in all and remains the treatment of choice for mediastinal parathyroid cysts.     

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.