Diagnosis and Therapeutic Management of Parathyroid Cysts

doi:10.4236/ss.2012.310095

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Surgical Science, 2012, 3, 479-483

http://dx.doi.org/10.4236/ss.2012.310095 Published Online October 2012 (http://www.SciRP.org/journal/ss)

Diagnosis and Therapeutic Management of

Parathyroid Cysts

Jean-Baptiste Finel, Stéphanie Mucci, Frédéric Branger, Aurélien Venara, Laure Blanchard,

Antoine Hamy*

Department of Digestive and Endocrine Surgery, University Hospital, Angers, France

Email: *[email protected]

Received July 21, 2012; revised August 25, 2012; accepted September 7, 2012

ABSTRACT

Objectives: The parathyroid cysts (PCs) are rare and their diagnosis and therapeutic management are not clearly estab-

lished. The aim of the study was to evaluate the characteristics of parathyroid cysts. Methods and Materials:

Twenty-five patients with PC were included in this retrospective study. The PCs were discovered as follows: cervical

mass (n = 18), screening for other pathologies (n = 7). Intracystic parathyroid hormone determination was performed in

6 cases. Results: Eight patients presented a hyperparathyroidism. Mean cyst size was 21.1 mm (ext 4 - 70 mm) by

19.8mm (5 - 45 mm). Twenty four cysts were cervical (resection by cervicotomy), and one was mediastinal (resection

by sternotomy). In addition to the resection of the PC, 3 adenomas, 1 hyperplasia of the parathyroid glands, 14 benign

thyroid diseases and 4 papillary carcinomas were recognized and treated during the cervicotomies. Conclusion: The

diagnosis of PC is uncommon and must be based primarily on the study of the cyst liquid obtained by percutaneous

puncture ( intracystic parat hyroid hormone measurement). T ru e PCs are no n f unctio na l .

Keywords: Hyperparathyroidism; Cystic Parathyroid; Intact Parathyroid Hormone

1. Introduction

Parathyroid cysts are rare and represent 1% - 3.3% of

parathyroid pathology [1]. They were present in 2.8% of

subjects in a set of autop sies [2]. In 1999, 250 cases were

described in the literature of which 94 cases were medi-

astinal. They have a variable presentation with local or

hormonal effects. Their treatment is most often surgical

(resection by the cervical or thoracic route). However in

certain cases, newly developed ultrasound guided fine

needle aspiration and sclerosing injections can be used in

their management [3,4]. We report a unicentric sample of

twenty-five patients managed in the department of Gen-

eral & Endocrine Surgery which allowed us to compare

our results and recommendations with those published in

the literature.

2. Patients and Methods

This retrospective study reviews the activity of the de-

partment of General & Endocrine surgery (University

Hospital of Angers) between the 1st of January 1986 and

the 31st of September 20 11. It consists of 25 patients, 19

females and 6 males with an average age of 51.3 years

(range: 22 - 83). The patients presented due to a cervical

mass in 18 cases and general health check-ups (osteopo-

rosis, obesity, HTA) in 7 cases.

Functional parathyroid cyst (FPC) is defined as a bio-

chemical primary hyperparathyroidism diagnosed before

surgery. In contrast, non functional parathyroid cyst

(NFPC) was considered in patients with normal level of

PTH and calcemia before surgery.

An ultrasound was performed for all patients. For 11

patients a scintigraphy was performed.

The parameters studied were the anatomical aspect,

the clinical characteristics and histological analysis of the

lesions.

3. Results

Among 25 patients with cystic parathyroid lesions, 20

(80%) had non functional cystic parathyroid lesions

(NFPC) and 5 (20%) had functional parathyroid cyst le-

sions (FPC).

Among these 25 parathyro id cysts, 3 lesions (2 NFPCs

and 1 FPC) were associated with parathyroid adenomas

and 1 with parathyroid hyperplasia.

Histological analysis revealed 4 cyst adenomas and all

of them were FPC. All of the 20 NFPCs were true cysts

parathyroid. The mean age is 51.3 years (22 - 83). The

principal localisation is inferior n = 15 (63%) and left n =

14 (58%).

*Corresponding a uthor.

J.-B. FINEL ET AL.

480

Twenty-four (96%) cysts were cervical and one cyst

was mediastinal. The cysts size on average 27 mm (range

= 5 - 70 mm) by 22 mm (5 - 45 mm). Hyperparathyroid-

ism (serum parathyroid hormone greater than 50 ng/ml)

was recor de d in 8 pati e n ts.

Six patients underwent ultrasound guided fine needle

aspiration under local anaesthetic to drain their cyst. The

intact PTH measurement in the cyst fluid ranged from 53

to 2661 pg/ml parathyroid (normal serum PTH is less

than 50). One patient had a first aspiration aimed purely

at alleviating their symptoms (without the measurement

of intracystic PTH). The cyst recurred and a new aspira-

tion was carried out with the measurement of PTH in the

cystic fluid (level of 685 pg/ml).

Eig hteen p atients h ad a single p arathyroid cyst associated

with other cervical pathology originating, in 4 cases, from

the other parathyroids (3 adenomas and 1 hyperplasia)

and, in 14 cases, from the thyroid (euthyroid on bio-

chemical testing).

In total 5 patients had more than one parathyroid gland

excised (1 hyperplasia, 3 adenomas and 1 normal para-

thyroid) and 14 thyroidecto mies were carried out (4 total,

10 subtotal) with associated parathyroidectomy.

The interventions were carried out by cervicotomy in

21, by first focused in 3 cases and sternotomy in 1 case.

In the later case the (asymptomatic) patient had initially

presented with a bronchogenic cyst.

Corresponding pathologies which were encountered

were: 1 case of parathyroid hyperplasia; 3 parathyroid

adenomas; 10 cases of benign thyroid disease and 4 pap-

illary carcinomas. All the interventions were uncompli-

cated without morbidity in particular without recurrence.

A summary of our observations is given in Table 1.

Table 1. Characteristics and surgical results of patients with parathyroid cyst.

Age

(year)

/Sex

(M/F)

Clinical

Presentation Hyperparathyroidism Diagnostic

Method Localisation Max Size

(mm) Treatment Histology

Serum PTH (1 -

84)*/Intracystic

PTH**

51/F Cervical mass No US L PIII 30 Surgery NFPC <10/2660

22/F Cervical

mass/recidive

ponction No US L PIII 20

Aspiration,

recurrence,

surgery NFPC N/685

75/M Multiple

sclerosis Yes US + Sc R PIII 23 Surgery FPC 240/NA

37/F Goiter No US + Sc R PIV 14 S ur g er y NFPC N/NA

30/F Goiter No US L PIII 13 Surgery NFPC 15/72

36/M Asymptomatic

thyroid nodule No US + Sc R PIV 20 Surgery NFPC N/NA

81/M Goiter Yes US + Sc L PIII 8 Surgery

(3 glands)

NFPC +

Hyperplasia

(2 glands) 132/NA

21/M Goiter No US + Sc L PIII 20 Surgery NFPC N/>65

62/F Osteoporosis Yes US + Sc R PIV 4 Surgery NFPC + adenoma <10/NA

46/F Cervical mass No US R PIV 12 Surgery NFPC NA/NA

40/F Cervical mass No US + Sc L PIII 15 Surgery NFPC 10/53

80/F Goiter No US + Sc L PIII 80 Surgery

(2 glands) NFPC + normal NA/NA

52/F Cervical mass No US L PIII 3 Surgery NFPC NA/NA

27/F Asymptomatic

thyroid nodule No US R PIII 25 Surgery NFPC N/210

39/M Goiter No US NA 6 Surgery NFPC NA/NA

80/F HTA Yes US + Sc L PIII 40 Surgery FPC 320/NA

83/F Osteoporosis Yes US + Sc L PIII NA Surgery FPC 110/NA

75/F Multiple

sclerosis Yes US + Sc R PIV 23 Surgery FPC 240/NA

61/F Review of

obesity No US

R PIV

(mediastinal) 70 Surgery

(sternotomy) NFPC NA/NA

40/M Goiter Yes US L PIV 30 Surgery

(2 glands) FPC + adenoma >55/NA

J.-B. FINEL ET AL. 481

Continued

39/F Goiter No US R PIV 10 Surgery NFPC N/NA

49/F Cervical mass No US L PIII 50 Surgery NFPC N/NA

28/F Goiter No US R PIII 5 Surgery NFPC N/NA

68/F Osteoporosis Yes US L PIV 15 Surgery (2

glands) NFPC + adenoma >55/NA

59/F Asymptomatic

thyroid nodule No US L PIII 40 Surgery NFPC N/NA

N normal, NA not assessed, L PIII left inferior parathyroid gland, L PIV left superior parathyroid gland, R PIII right inferior parathyroid gland, US ultrasound,

Sc scintigraphy. R PIV right superior parathyroid gland, FPC functional parathyroid cyst, NFPC non functional parathyroid cyst. *10 < N < 55 pg/ml. **Intact

PTH (normal < 65 pg/ml).

4. Discussion

During the course of the study 538 patients underwent

operations for parathyroid pathology and 5663 for thy-

roid pathology in our department thus there were just

over 6000 cervicotomies for cervical, endocrine pathol-

ogy. Parathyroid cysts account for 4.6% of parathyroid

pathologies managed surgically and 0.41% of cervicoto-

mies carried out. Our sample is representative of the lit-

erature with a predominence of female subjects (sex ratio

= 3.2), patients in the fourth and fifth decade are most

commonly affected [5,6].

Generally parathyroid cysts present with a solitary le-

sion at the laterocervical base [7-9] and preferentially

localise to the left [1,9]. Most commonly there is a soli-

tary, uninodular lesion; however Delaunay et al. raised

the possibility of multiple cysts in 3% of cases [1]. Mul-

tinodular cysts have also been described relating to cysts

within adenomas [2]. On average the size of cysts varies

between 3 and 5 cm [7] with a fluid content between 2

and 75 ml [10]. Mediastinal cysts have been described

with a size of up to 12 cm [11]. Many hypotheses have

been suggested to explain the development of parathy-

roid cyst: degeneration or bleeding of the parathyroid

gland or an adenoma which forms active cysts in the

parathyroid cell wall [7,8] development of embriological

residuals [12,13] retention of the secretions of the colloid

vesicles or enlargement of microcysts by retention [14]

forming inactive cysts with a clear liquid.

The circumstances of discovery are variable. It can be

a chance discovery on examination with the suspicion of

thyroid pathology (goiter, nodule) or other cervical mass

(carotid vessels, adenopathies etc.) or during surgery in

the area concerned [2,15] (14 in our observation). Else-

where examination will note a palpable anterior cervical

mass [2,16] or laterocervical base masses [15,17] which

is smooth, renitent and mobile presenting like a thyroid

nodule. The cervico-mediastinal cysts can give the im-

pression of a plunging goitre [11]. This mass can appear

serious if associated with pain (raising suspicion of a

haemorrhagic complication). The diagnosis is eventually

considered with associated hypercalcemia [18]. You will

not find adenopathy in our study.

Typically these cysts, even those discovered in asso-

ciation with cervical mass conditions, are asymptomatic.

Rarely there are clinical signs corresponding to a com-

plication: cervical pain [1,3,11,19] and/or thoracic pain

[18] or compression symptoms [3,8,11,16,18-20], dys-

pahgia (one of our observations), dysphonia [5,20] dysp-

noea, dry cough or stridor [15,21] deviatio n and vascular

compression [11,18,22]. Systemically the patient will be

normal unless the cyst causes significant hyperparathy-

roidism which itself can be symptomless.

Parathyroid cysts can be functional and secretary,

causing hyperparathyroidism in 10% - 15% of cases

[3,5,20,23], 20% in our trial. Only 1% - 5% of cases of

hyperparathyroidism are caused by parathyroid cysts (in

our experience there were five FPCs every 538 cervi-

cotomies for parathyroid pathology, 0.9%) FPCs, most

frequently encountered in male patients, are typically

degenerative or are bleeds from an adenoma [14,16,21].

Their content is brownish or bloody [1]. The cyst does

not have a clear epith elial wall and is lined with parathy-

roid tissue [1,4,14]. Thus they are pathologically recog-

nisable.

It is not misleading to describe inactive or non-func-

tional cysts as parathyroid. They contain a clear mucous

fluid [1,11,13]. Parathyroid tissue is found on histologi-

cal examination forming islands surrounded by fibrous

tissue, this confirms the parathyroid nature of the cyst

[1,11,14,20,21].

Associations have been noted with other parathyroid

pathologies (hyperplasia (1case), adenoma of another

parathyroid gland responsible for hyperparathyroidism [2,

13] 3 of our observations) or can be incidental findings in

thyroid disease [24].

One of our observations concerned a mediastinal cyst.

Its localisation has been widely reported in the literature

where 94 of 250 cysts listed were parathyroid [11]

meaning that the incidence of mediastinal glands is be-

tween 2.5% - 22% [10,17,19,22]. The cysts (active in

42% of cases [2]) are most often situated anterior to the

mediastinum (82%) where they occur as cysts on inferior

ectopic glands.

Imaging—in particular ultrasound—only confirms the

J.-B. FINEL ET AL.

482

cystic nature of the lesion without differentiating between

parathyroid cysts and other types of cysts [17,25]. On

fine needle aspiration the fluid colour is variable: clear

like mineral water (nearly always pathogenic of a para-

thyroid cyst [5] or milky, bloody etc. (suggestive of a

thyroid cyst [5,6]) The presence of parathyroid hormone

(PTH) in the aspirate fluid confirms the parathyroid na-

ture of the cyst [2,11,12,25] but does not allow a ruling

on the activity level of the cyst because the PTH concen-

tration in the cystic fluid can be greater than the PTH

concentration in the blood in either type of cyst (FPCs or

NFPCs) [6,25]. Only blood biochemistry can tell the dif-

ference between FPCs or NPCs. For some, the concen-

tration of carboxyterminel fragments of PTH in the aspi-

rate fluid is more interesting and a better measure than

the whole hormone [2,11,21,26]. The aspirate fluid of

parathyroid cyst is acellular and does not contain thyroid

hormones.

Fine Needle Aspiration allows the diagnosis between

rarer parathyroid cysts and thyroid cysts, which are often

falsely suspected, to be made [5,8,17,20,23]. In thyroid

cysts the intracystic level of thyroid hormones and thy-

roglobulin is raised while the level of PTH is zero

[8,20,27].

Aside from their diagnostic role, ultrasound guided

FNA can treat cysts by drainage but recurrence is always

a possibility (one of our observations). In these cases

surgery [3,8,20,22,28] repeated fine needle aspiration

until the cyst disappears [1,2,23] or intracystic injections

to cause sclerosis (tetracycline [27] or ethanol [3,4]) can

then be considered. Intracystic injections are accompa-

nied by pain, fever and transient breathlessnesss in 5% of

cases [4,6,20]. This technique presents risks of pericystic

fibrosis (especially with ethanol injections) which can

lead to recurrence of the cyst [3]. It is fo r this reason that

Verges et al. advise that whilst carrying out the technique

one should speak to the patient and, at the slightest sug-

gestion of dysphonia, should stop the procedure (4 tran-

sient dysphonias out of 13 patients in their trial) [29]. It

appears that recovery can be established without the need

for subsequent sclerosing injections [27,28].

In a study of 37 patients Ippolito et al. [25] treated 14

patients by fine needle aspiration (FNA). There were 4

recurrences, all of them treated by surgery. They con-

cluded, FNA is diagnostic due to the characteristic ap-

pearance of the fluid and high PTH levels but can also be

curative. However recurrences exist and will have to be

treated by surgery [25].

In the context of an active parathyroid cyst surgical

excision seems the obvious choice [1,2,5,7,13,27] with

an extemporaneous histological examination of the sur-

gical specimen. This dissection can be difficult due to the

hypervascular character of the cyst and the fact that it can

be embedded in the thyroidal parenchyma which can lead

to associated resection of the thyroid gland [30]. The

three remaining parathyroid glands must also be explored

to look for double localisations and associations; how-

ever some suggest that it may be sufficient to only ex-

plore the unilateral parathyroid gland [30]. Severe hy-

percalcemia indicates a fine needle aspiration in order to

treat the hypercalcemia [1], primary sclerotherapy [29]

can permit a secondary surgical removal with the patient

in a better metabolic state. The intervention can be

guided by the perioperative PTH levels.

5. Conclusion

The indications for surgical or radiological interventions

essentially depend on whether or not the cyst is active

and on its localisation which determines the possib ility of

fine needle aspiration. True PCs are non functional. Post

therapeutic surveillance of calcium levels is a necessary

requirement for the early detection of a recurring cyst or

other parathyroi d al patholo gy.

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