Abstract
Ectopic parathyroid adenomas in the mediastinum are rare causes of primary hyperparathyroidism. We report two cases of mediastinal parathyroid adenoma. Functioning parathyroid lesion was localized with the help of nuclear single-photon emission computed tomography scan in both the patients. Video assisted thoracoscopic surgical (VATS) removal of the parathyroid lesions were done. Intraoperative confirmation of parathyroid adenoma was done by frozen section. Further confirmation was done by routine histopathological examination of specimen postoperatively. One patient had left vocal cord paralysis postoperatively. Localization by functional imaging is essential. Minimally invasive methods such as VATS are useful in removing mediastinal parathyroid hyperfunctioning lesions, which carries early postoperative recovery and less complications.
Keywords: Mediastinal parathyroid adenoma, nuclear single-photon emission computed tomography, thoracoscopic surgery, Adénome parathyroïdien médiastinal, tomodensitométrie par émission de photons uniques nucléaires, chirurgie thoracoscopique
Résumé
Les adénomes parathyroïdes ectopiques dans le mediastinum sont des causes rares de l’hyperparathyroïdie primaire. Nous rapportons deux cas d’adénome parathyroïde mediastinal. La lésion parathyroïde de fonctionnement a été localisée avec l’aide du balayage nucléaire de SPECT dans les deux patients. L’enlèvement thoracoscopic aidé vidéo de chirurgie (VATS) des lésions parathyroïdes ont été faits. La confirmation intraopératoire de l’adénome parathyroïde a été faite par section gelée. Une confirmation supplémentaire a été faite par l’examen histopathologique courant du spécimen post opératoirement. Un patient avait laissé la paralysie de corde vocale postopératoirement. La localisation par imagerie fonctionnelle est essentielle. Les méthodes mini-invasives telles que le VATS sont utiles pour enlever les lésions de fonctionnement hyper-médiantinal, qui portent le rétablissement postopératoire tôt et moins de complications.
INTRODUCTION
Parathormone (PTH) is a crucial hormone in calcium homeostasis. Primary hyperparathyroidism can be asymptomatic or present with a wide spectrum of symptoms. Rarely, patients are admitted with hypercalcemic crisis.[1] Primary hyperparathyroidism can present as hypercalcemic hyperparathyroidism or normocalcemic hyperparathyroidism. The occurrence of complications in normocalcemic hyperparathyroidism such as osteoporosis and urolithiasis are similar compared to hypercalcemic ones. Most of these patients with normocalcemic hyperparathyroidism were investigated for complications, and hence, it was overestimated.[2] Single parathyroid adenoma is the most common followed by double adenoma. The ectopic parathyroid glands are located in the thymus (38%), retroesophageal region (31%), and intrathyroidal region (18%).[3] Functional imaging is essential in localization of these lesions. Dual-phase 99mTc-MIBI with single-photon emission computed tomography/computed tomography (SPECT/CT) is an accurate and reliable method of localizing ectopic parathyroid adenomas for the purpose of surgical planning.[4] Video-assisted thoracoscopic surgical (VATS) removal of ectopic parathyroid adenoma is a newer option.[5]
CASE REPORTS
Case report 1
A 42-year-old female patient was investigated for a history of recurrent renal calculi. She had undergone extracorporeal shockwave lithotripsy recently. Clinical examination was unremarkable. Laboratory investigations showed hypercalcemia with elevated 24 hour urinary calcium. Nuclear SPECT showed a functional ectopic parathyroid lesion in the anterior mediastinum [Figure 1]. VATS removal of parathyroid lesion was done. Intraoperative confirmation of parathyroid adenoma was done by frozen section. Further confirmation was done by routine histopathological examination of specimen postoperatively [Figures 2 and 3]. Her calcium, phosphorus, and PTH (39.5 pg/ml) were within the normal range, 48 h after the surgery. She was discharged with calcium and Vitamin D as she had Vitamin D deficiency. Follow-up showed PTH in normal range with normocalcemia.
Figure 1.
Nuclear single-photon emission computed tomography/computed tomography showed a functional ectopic parathyroid lesion in the anterior mediastinum of the first patient
Figure 2.
Parathyroid adenoma of the first patient (low-power view)
Figure 3.
Parathyroid adenoma of the first patient (high-power view)
Case report 2
A 63-year-old male known case of diabetes mellitus and systemic hypertension came with generalized body pain, recurrent renal calculi, and intermittent constipation for 2 years. Clinical examination was unremarkable. Laboratory investigations showed hypercalcemia with elevated 24 hour urinary calcium. Nuclear SPECT showed a functional parathyroid lesion in the anterior mediastinum [Figure 4]. VATS removal of parathyroid lesion was done. Intraoperative confirmation of parathyroid adenoma was done by frozen section. Further confirmation was done by routine histopathological examination of specimen postoperatively. His calcium, phosphorus, and PTH were within the normal range, 48 h after the surgery. He developed left vocal cord paralysis postoperatively. He was discharged with Vitamin D as he also had Vitamin D deficiency. Follow-up showed a persistent left vocal cord paralysis with normocalcemia after 4 months. He had a mild elevation in PTH after 4-month follow-up. He was lost follow-up with the endocrinology department; hence, 24-h urinary calcium and nuclear imaging were not done.
Figure 4.
Nuclear single-photon emission computed tomography/computed tomography showed a functional ectopic parathyroid lesion in the anterior mediastinum of the second patient
DISCUSSION
Both the patients had hypercalcemia and elevated PTH with hypercalciuria [Table 1]. Both of them had a hyperfunctioning ectopic parathyroid lesion in the mediastinum, and localization was done with the help of nuclear SPECT scan. Both the patients had a good recovery and showed an improvement in their symptoms, except that the second patient had vocal cord paralysis postoperatively. Any patient with low Vitamin D should not be ignored. Prescribing vitamin supplement alone will not solve the problem. Those patients should be worked up properly to exclude hyper functioning parathyroid lesions in the setting of elevated parathormone. Twenty-four-hour urinary calcium will be elevated in primary hyperparathyroidism, and it was not significantly altered by Vitamin D deficiency with primary hyperparathyroidism.[6]
Table 1.
Laboratory parameters of two patients
| Preoperative values | Patient 1 | Patient 2 |
|---|---|---|
| Calcium (g/dl) | 10.4 | 12.2 |
| Phosphorous (mg/dl) | 2.3 | 3.2 |
| Alkaline phosphatase (U/L) | 67 | 71 |
| Vitamin D (ng/ml) | 6.5 | 11.8 |
| PTH (pg/ml) | 212.5 | 178 |
| 24-h urinary calcium (mg) | 321.75 | 206.04 |
| 24-h urinary metanephrine (µg) | 48 | 110 |
| 24-h urinary normetanephrine (µg) | 357 | 358 |
|
| ||
| Follow-up | 1 month | 4 months |
|
| ||
| PTH (pg/ml) | 32 | 83.8 |
PTH=Parathormone, 24 hour urinary metanephrine: <350 μg/24 hrs, 24 hour urinary normetanephrine: <600 μg/ 24 hrs
Both had renal stones, and the second patient also had constipation. Untreated hyperparathyroidism leads to complications such as peptic ulcer disease, renal dysfunction, renal calculus, hypercalcemic crisis, ventricular conduction defect, and even death due to complications.[7] Minimally invasive surgeries in general have less complications and ensure early recovery and reduced hospital stay. Parathyroid adenoma removal by VATS, as it is minimally invasive, also had all these advantages.[8]
We reviewed few case series in that 41 patients with primary hyperparathyroidism undergone VATS procedure for mediastinal hyper functioning parathyroid tissue (histologically proven) and only few had complications such as recurrent laryngeal nerve injury and hemothorax [Table 2].[8,9,10,11,12,13] VATS is a safe procedure with minimal complications and ensures early postoperative recovery.
Table 2.
Literature review of hyperfunctioning parathyroid tissue removed by video-assisted thoracoscopic surgery
| Case series | Number of patients undergone VATS procedure | Comments |
|---|---|---|
| Amer et al.[8] | 6 | Outcome: Cured |
| Alesina et al.[9] | 6 | Outcome: Cured |
| Amar et al.[10] | 3 | Outcome: Cured |
| One patient had left recurrent laryngeal nerve injury | ||
| Wei et al.[11] | 13 | Outcome: Cured |
| One patient had temporary left vocal cord paresis | ||
| Said et al.[12] | 9 | Outcome: Cured |
| Reoperation in one patient for hemothorax due to left internal thoracic laceration | ||
| Al-Githmi[13] | 4 | Outcome: Cured |
VATS: Video-assisted thoracoscopic surgery
Intraoperative radionuclide-guided dissection is useful in the removal of ectopic parathyroid glands.[14,15] Intraoperative confirmation by frozen section is also helpful. In our patients, frozen section was done to confirm the hyperfunctioning parathyroid tissue. However, these patients should be investigated for any other features of multiple endocrine neoplasia (MEN) syndrome. These patients should be followed up regularly. History of parathyroid illness or any other features of MEN syndrome in family members needs proper workup. Molecular studies may be needed, if available.
In the setting of elevated PTH with Vitamin D deficiency, 24-h urinary calcium estimation will be helpful to suspect hyperfunctioning parathyroid lesion. If hyperparathyroidism is suspected based on biochemical tests, functional imaging is required for localization. Frozen section is helpful intraoperatively and avoids incomplete removal of hyperfunctioning parathyroid tissue. VATS is a better option for mediastinal hyperfunctioning parathyroid lesions. Follow-up is essential to find out recurrence and any other features of MEN.
Declaration of patient consent
The authors certify that they have obtained Institutional ethics committee approval for the publication of these case reports. Patients names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
REFERENCES
- 1.Girish P, Lala M, Chadha M, Shah NF, Chauhan PH. Study of primary hyperparathyroidism. Indian J Endocrinol Metab. 2012;16:S418–20. doi: 10.4103/2230-8210.104114. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Baranova IA, Zykova TA. Normocalcemic primary hyperparathyroidism - “new era” in diagnosis of an old disease. Problems of Endocrinology. 2017;63:236–44. [Google Scholar]
- 3.Roy M, Mazeh H, Chen H, Sippel RS. Incidence and localization of ectopic parathyroid adenomas in previously unexplored patients. World J Surg. 2013;37:102–6. doi: 10.1007/s00268-012-1773-z. [DOI] [PubMed] [Google Scholar]
- 4.Wong KK, Fig LM, Gross MD, Dwamena BA. Parathyroid adenoma localization with 99mTc-sestamibi SPECT/CT: A meta-analysis. Nucl Med Commun. 2015;36:363–75. doi: 10.1097/MNM.0000000000000262. [DOI] [PubMed] [Google Scholar]
- 5.Kim YS, Kim J, Shin S. Thoracoscopic removal of ectopic mediastinal parathyroid adenoma. Korean J Thorac Cardiovasc Surg. 2014;47:317–9. doi: 10.5090/kjtcs.2014.47.3.317. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Bussey AD, Bruder JM. Urinary calcium excretion in primary hyperparathyroidism: Relationship to 25-hydroxyvitamin d status. Endocr Pract. 2005;11:37–42. doi: 10.4158/EP.11.1.37. [DOI] [PubMed] [Google Scholar]
- 7.Corlew DS, Bryda SL, Bradley EL, 3rd, DiGirolamo M. Observations on the course of untreated primary hyperparathyroidism. Surgery. 1985;98:1064–71. [PubMed] [Google Scholar]
- 8.Amer K, Khan AZ, Rew D, Lagattolla N, Singh N. Video assisted thoracoscopic excision of mediastinal ectopic parathyroid adenomas: A UK regional experience. Ann Cardiothorac Surg. 2015;4:527–34. doi: 10.3978/j.issn.2225-319X.2015.09.04. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Alesina PF, Moka D, Mahlstedt J, Walz MK. Thoracoscopic removal of mediastinal hyperfunctioning parathyroid glands: Personal experience and review of the literature. World J Surg. 2008;32:224–31. doi: 10.1007/s00268-007-9303-0. [DOI] [PubMed] [Google Scholar]
- 10.Amar L, Guignat L, Tissier F, Richard B, Vignaux O, Fulla Y, et al. Video-assisted thoracoscopic surgery as a first-line treatment for mediastinal parathyroid adenomas: Strategic value of imaging. Eur J Endocrinol. 2004;150:141–7. doi: 10.1530/eje.0.1500141. [DOI] [PubMed] [Google Scholar]
- 11.Wei B, Inabnet W, Lee JA, Sonett JR. Optimizing the minimally invasive approach to mediastinal parathyroid adenomas. Ann Thorac Surg. 2011;92:1012–7. doi: 10.1016/j.athoracsur.2011.04.091. [DOI] [PubMed] [Google Scholar]
- 12.Said SM, Cassivi SD, Allen MS, Deschamps C, Nichols FC, 3rd, Shen KR, et al. Minimally invasive resection for mediastinal ectopic parathyroid glands. Ann Thorac Surg. 2013;96:1229–33. doi: 10.1016/j.athoracsur.2013.05.084. [DOI] [PubMed] [Google Scholar]
- 13.Al-Githmi I. Minimally invasive mediastinal parathyroidectomy: An effective and safe technique in patients with ectopic primary hyperparathyroidism. Open J Thorac Surg. 2017;7:70–6. [Google Scholar]
- 14.Ott MC, Malthaner RA, Reid R. Intraoperative radioguided thoracoscopic removal of ectopic parathyroid adenoma. Ann Thorac Surg. 2001;72:1758–60. doi: 10.1016/s0003-4975(01)02652-2. [DOI] [PubMed] [Google Scholar]
- 15.Sullivan DP, Scharf SC, Komisar A. Intraoperative gamma probe localization of parathyroid adenomas. Laryngoscope. 2001;111:912–7. doi: 10.1097/00005537-200105000-00030. [DOI] [PubMed] [Google Scholar]