Intrathyroidal parathyroid glands can be a cause of failed cervical exploration for hyperparathyroidism

How often are intrathyroidal parathyroid glands a cause of primary hyperparathyroidism, and how should they be managed?

BACKGROUND

The purpose of our study was to determine the frequency and management of intrathyroidal parathyroid glands in patients with primary hyperparathyroidism and evaluate whether intrathyroidal parathyroid glands were more often superior or inferior glands.

METHODS

A retrospective review of the prospective parathyroid database was completed to determine the number of patients with primary hyperparathyroidism and an intrathyroidal parathyroid gland. Demographic data, laboratory and localization studies, operative management, pathology, and outcome were determined for patients with an intrathyroidal parathyroid gland and were compared with patients with an extrathyroidal parathyroid gland.

RESULTS

From 1990-2023, 808 patients were operated on for primary hyperparathyroidism; 17 (2%) patients had an intrathyroidal parathyroid gland, an adenoma in 15 (88.2%), and a hyperplastic gland in 2 (11.8%). The mean age was 53 years; 16 (94%) patients were female. Mean calcium and parathyroid hormone was 12 mg/dL and 150 pg/mL, and there were no differences from the extrathyroidal parathyroid group. Ultrasound and Sestamibi imaging were valuable in identifying an intrathyroidal parathyroid gland in 10 of 13 patients and 13 of 17 patients, respectively. Local excision was performed in 9 (53%) patients and lobectomy in 8 (47%) patients. Intraoperative parathyroid hormone was measured and predictive of cure in 12 patients. The location of intrathyroidal parathyroid glands was determined in 15 patients and was inferior in 11 (73%). All patients were cured. No patient developed recurrent disease after a median 54-month follow-up.

CONCLUSION

Intrathyroidal parathyroid glands are the cause of primary hyperparathyroidism in 2% of patients and are most often inferior glands. Local excision was accomplished in 53% of our patients.

Surgical tips and techniques to avoid complications of thyroid surgery

Objectives

Surgery of the thyroid takes place in a body part with complicated anatomy and several vital physiologic functions. Thyroidectomy is rarely associated with mortality but can be followed by significant complications, (i.e. hypoparathyroidism, hemorrhage, upper airway obstruction, laryngeal nerve injuries and thyrotoxic storm). This review aims to indicate surgical tips and techniques to sustain a low level of complications.

Content

MEDLINE database (PubMed) platform was used as a search engine and the articles related to the topic were selected using the keywords combination "thyroid surgery and complications".

Summary and Outlook

The most common complication of total thyroidectomy with an occurrence ranging between 0.5 and 65% is hypoparathyroidism. Damage to recurrent laryngeal nerves can be temporary or permanent, unilateral or bilateral; bilateral lesion is associated with severe episodes of breathlessness. Thus, intraoperative monitoring of nerve function is essential to prevent damage. Ιn addition, hematoma formation can lead to breathing difficulties due to airway obstruction; preventive hemostasis during surgery is essential. The surgeon must have a complete anatomical understanding of not only the normal anatomy of the central visceral compartment of the neck, but also the common variations of the laryngeal nerves and parathyroid glands in order to keep the complication rate at a very low level.

Preventing blind thyroid lobectomy in patients with intrathyroidal hyperfunctioning parathyroid glands with radioguided enucleation

Aim: Hyperfunctioning intrathyroidal parathyroid glands are rare and often result in thyroid lobectomy. This study examines the utility of radioguided surgery to guide enucleation of intrathyroidal parathyroids. Methods: Between December 2002 and March 2018, 2291 patients underwent parathyroidectomy by one surgeon for primary hyperparathyroidism. A total of 74 (3%) patients had an ectopic intrathyroidal parathyroid gland and underwent radioguided. Results: All of intrathyroidal parathyroid glands were localized with the gamma probe. In vivo radionuclide counts were above 120% of the background in all but three patients. All intrathyroidal parathyroids were enucleated with the guidance of the gamma probe. Conclusion: Radioguided surgery is useful for intraoperative identification of hyperfunctioning, intrathyroidal parathyroid glands. This technique allows for enucleation of the abnormal parathyroid gland, avoiding thyroid lobectomy and preserving healthy thyroid parenchyma.

Characterization of Thyroid Nodules by 4-Dimensional Computed Tomography: Initial Experience

OBJECTIVE

We aimed to evaluate the use of 4-dimensional computed tomography (4DCT) for characterization of thyroid nodules.

METHODS

Our study drew from 100 consecutive patients with primary hyperparathyroidism who underwent 4D parathyroid CT imaging for adenoma localization. Included subjects had tissue sampling of a thyroid nodule within 3 months of 4DCT.

RESULTS

Twenty subjects (18 women and 2 men) had thyroid nodules that were pathologically confirmed. Precontrast nodule attenuation was significantly lower in malignant nodules when compared with benign nodules (36 vs 61 HU, P = 0.05). Arterial phase and delayed phase nodule attenuations were not significantly different in malignant and benign nodules (128 vs 144 HU, P = 0.7; 74 vs 98 HU, P = 0.3).

CONCLUSIONS

Our initial experience with a small group of patients was unable to support the use of 4DCT for characterizing thyroid nodules; however, precontrast nodule attenuation was significantly lower in malignant nodules when compared with benign nodules.

Incidental parathyroidectomy during thyroidectomy increases the risk of postoperative hypocalcemia

OBJECTIVES/HYPOTHESIS

The correlation between incidental parathyroidectomy (IP) during thyroidectomy and postoperative hypocalcemia remains controversial. Our aim was to investigate the incidence of IP, risk factors, and impact on patient outcomes.

STUDY DESIGN

Retrospective cohort study.

METHODS

This was a retrospective observational study including 3,186 consecutive patients who underwent thyroidectomy between January 2007 and December 2014. The patients were divided into two groups: the IP group and the non-IP. Numerous clinical parameters were collected and analyzed.

RESULTS

The overall incidence of incidentally excised parathyroid glands during thyroidectomy was 6.4%. Patients with IP had significantly higher incidences of postoperative hypocalcemia and hypoparathyroidism than those without IP (P < 0.001). Intrathyroidal parathyroid glands presented only 2.2% of all removed parathyroid glands. Total thyroidectomy, central compartment lymph node dissection, and reoperation were independent risk factors for IP.

CONCLUSION

Incidental parathyroidectomy during thyroidectomy is associated with the increased likelihood of postoperative hypocalcemia. All independent risk factors examined in the study for IP are surgery-related. Surgeons should perform meticulous dissection with the intention of avoiding IP and resultant hypocalcemia.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:2194-2200, 2017.

[Intrathyroidal location of parathyroid glands. Atypical presentation of multiple endocrine neoplasia type 1 syndrome]

BACKGROUND

The most common manifestation of MEN 1 syndrome is primary hyperparathyroidism (PHPT) with parathyroid multiglandular affectation. The intrathyroidal situation represents 3-4% of all glands, and it is the second most frequent location in the cervical ectopias.

CLINICAL CASE

11 year old patient, with a family history of MEN1 syndrome and carrier of this same mutation. Patient presents HPTP with osteopenia. The cervical ultrasound shows three compatible images with pathological parathyroid glands (bilateral lower and upper left). The Scan and MRI are normal. Bone densitometry displays data on osteopenia. The patient is surgically intervened, only the upper parathyroid glands are located and removed, after this implantation is performed on the forearm, to prevent the possible devascularization in the dissection of the other glands. However, osteopenia persists and an elevated PTH, therefore new diagnostic tests are held which seem to show two lower parathyroid glands with intrathyroidal location. The patient is reoperated. A subtotal parathyroidectomy of the lower right gland and the resection of the left gland is performed, with the use of intraoperative ultrasound and placement of harpoon. The intraoperative pathology study confirms parathyroid tissue in both cases.

DISCUSSION

It is necessary to locate the parathyroid glands preoperatively in order to alert us of the existence of topographical and ectopia abnormalities, as well as their intrathyroidal location (0.5-3.6%).

CONCLUSION

The intraoperative ultrasound can be a complement to the experience of the endocrine surgeon for the localization of the parathyroid glands and therefore can help determine the best surgical strategy for each clinical case.

The role of ultrasound and nuclear medicine methods in the preoperative diagnostics of primary hyperparathyroidism

Primary hyperparathyroidism (PH) represents one of the most common endocrine diseases. In most cases, the disorder is caused by parathyroid adenomas. Bilateral neck exploration has been a widely used treatment method for adenomas since the 20's of the twentieth century. In the last decade, however, it has been increasingly replaced by a minimally invasive surgical treatment. Smaller extent, shorter duration and lower complication rate of such a procedure are emphasized. Its efficacy depends on a precise location of parathyroid tissue during the preoperative imaging. Scintigraphy and ultrasound play a major role in the diagnostic algorithms. The efficacy of both methods has been repeatedly verified and compared. The still-current guidelines of the European Association of Nuclear Medicine (2009) emphasize the complementary role of scintigraphy and ultrasonography in the preoperative diagnostics in patients with primary hyperparathyroidism. At the same time, attempts are made to improve both these techniques by implementing new study protocols or innovative technologies. Publications have emerged in the recent years in the field of ultrasonography, whose authors pointed out the usefulness of elastography and contrast media. Nuclear medicine studies, on the other hand, focus mainly on the assessment of new radiotracers used in the positron emission tomography (PET). The aim of this article is to present, based on literature data, the possibilities of ultrasound and scintigraphy in the preoperative diagnostics in patients with primary hyperparathyroidism. Furthermore, the main directions in the development of imaging techniques in PH patients were evaluated.

Identification of parathyroid glands: anatomical study and surgical implications

While performing thyroid surgery, the unintentional lesion of parathyroid glands and laryngeal nerves results in a profound alteration in patient's quality of life. To minimize thyroid surgery morbidity, the surgeon must have an in-depth knowledge of the thyroid gland morphology and its anatomical relations in the anterior compartment of the neck. This work intended to simulate total thyroidectomies using cadaver parts and isolate fragments that may correspond to parathyroid glands. The thyroid glands and "eventual" parathyroid glands were then submitted to histological study. Ninety-two cadaver parts were used for macroscopic dissection. A total of 242 fragments were isolated, 154 of which were confirmed through histological study to be parathyroid glands. In 36 cases, all "eventual" parathyroid glands isolated during dissection were confirmed through histological verification. In 40 cases, some glands were confirmed. In 16 cases, none of the "eventual" parathyroid glands was confirmed. The 92 thyroid glands isolated during dissection were also submitted to histological study. In 21 thyroid glands, 16 parathyroid glands were identified in the histological cuts: 8 sub-capsular, 8 extra-capsular, 6 intra-thyroidal. There was no statistical difference between the dimensions of the parathyroid glands. Parathyroid gland identification and preservation are sometimes a challenge during thyroid surgery, difficulty that has been demonstrated during dissection of cadaver parts.

Intrathyroidal parathyroid glands: small, but mighty (a Napoleon phenomenon)

BACKGROUND

Intrathyroidal parathyroid adenomas (ITPAs) are a rare entity. The aim of this study is to describe the experience of 2 endocrine surgery centers and to distinguish characteristics of intrathyroidal parathyroid adenoma and nonintrathyroidal parathyroid adenomas.

METHODS

We included patients who had undergone operations for primary hyperparathyroidism who had intrathyroidal parathyroid adenomas. Patients with single intrathyroidal parathyroid adenomas were also compared to age- and sex-matched controls with nonintrathyroidal parathyroid adenomas.

RESULTS

Of 4,868 patients who underwent parathyroidectomy between January 2002 and June 2011, we identified 53 (1%) patients with intrathyroidal parathyroid adenoma. Sestamibi and ultrasound scans correctly identified the adenoma in 35 (70%) and 11 (61%) cases, respectively. Single adenomas were identified in 44 (83%) patients, double adenomas in 4 (8%) patients, and hyperplasia in 5 (9%) patients. Lobectomy was performed in 17 (32%) patients; enucleation was used in 36 (68%) patients. Cure was achieved in all patients and no patients experienced a recurrence. Patients with single intrathyroidal parathyroid adenomas had significantly smaller glands than patients with nonintrathyroidal parathyroid adenomas (325 ± 47 vs 772 ± 61 mg; P < .0001); however, no significant difference was identified between the groups with regard to demographics, symptoms, preoperative laboratory values, or outcomes.

CONCLUSION

Single intrathyroidal parathyroid adenomas are smaller than nonintrathyroidal parathyroid adenomas, but patients with intrathyroidal parathyroid adenomas present with similar laboratory values and symptoms. Recognition of this rare entity can lead to a successful surgical outcome.

Giant intrathyroidal parathyroid adenoma

Primary hyperparathyroidism (PHPT) is not an uncommon endocrine disorder. However, acute primary hyperparathyroidism, or parathyroid crisis (PC), is a rare clinical entity characterized by life-threatening hypercalcemia of a sudden onset in patients with PHPT. We describe a patient with PC who presented with acute worsening of depressive symptoms, nausea and vomiting, and required emergency surgery. Serum calcium, alkaline phosphatase, and parathyroid hormone were elevated and serum phosphorus was low. An emergency hemithyroidectomy was performed because of none medical control of hypercalcemia. A giant intrathyroidal parathyroid adenoma was diagnosed. PHTP can be a life-threatening situation for patients, requiring immediate surgical treatment. A giant intrathyroidal parathyroid adenoma is an uncommon cause of PC.

Intrathyroid parathyroid adenoma: incidence and location--the case against thyroid lobectomy

OBJECTIVE

It has been taught that a missing parathyroid adenoma can be within the thyroid. Therefore, thyroid lobectomy is appropriate when an adenoma cannot be found. Unfortunately, this technique is often futile. The purpose of this study is to examine the frequency of unsuccessful thyroid lobectomy in parathyroid surgery and to look at the true incidence and location of intrathyroid parathyroid adenomas (iT-PAs).

STUDY DESIGN

A retrospective chart review of 11,163 patients undergoing parathyroid surgery identifying the location of more than 40,000 parathyroid glands.

SETTING

A tertiary care center specializing in parathyroid surgery.

SUBJECTS AND METHODS

A total of 1163 reoperations for persistent primary hyperparathyroidism (PHPT) were examined for the incidence and outcomes of thyroid lobectomy performed to find iT-PA. A second study examined 10,000 patients undergoing first-time parathyroidectomy to classify the location and incidence of iT-PA.

RESULTS

Thyroid lobectomy had been previously unsuccessfully performed in 77% cases of PHPT undergoing reoperation. Two or fewer glands were found in 82% prior to lobectomy. The adenoma was subsequently found on the lobectomy side in 64% and on the opposite side in 36%. True iT-PA occurred in only 0.7% of 10,000 primary cases. Another 1.2% were closely adherent to or partially within the thyroid substance. The most common location was the lower lateral quadrant of the thyroid.

CONCLUSION

The incidence of true iT-PA is less than 1%, occurring in predictable locations. Thyroid lobectomy for a missing parathyroid adenoma is typically unsuccessful and should only rarely, if ever, be performed.

Successful removal of intrathyroidal parathyroid adenoma diagnosed and accurately located preoperatively by parathyroid scintigraphy (SPECT-CT)

We describe the case of a large intrathyroidal parathyroid adenoma in a 46-year-old woman who had a history of recently diagnosed hypercalcaemia and a 2-year history of an asymptomatic enlargement of the right lobe of the thyroid. This rare case highlights the potential difficulties that can arise in the evaluation of hyperparathyroidism, especially in cases of multinodular goiter. In some cases, including this one, even a thorough preoperative evaluation that includes radiological studies (ultrasonography and computed tomography [CT]) may not allow for a definitive preoperative diagnosis due to limited sensitivity, especially in multinodular goiter. The overlapping histological features between thyroid and parathyroid lesions can also be problematic at the time of the intraoperative frozen-section evaluation. We present a case in which, with parathyroid scintigraphy and combination of structural and functional imaging (SPECT-CT), we could accurately locate the intrathyroidal parathyroid adenoma in a patient with multinodular goiter.

How to minimize complications in thyroid surgery?

BACKGROUND

In ancient times, operations on the thyroid gland caused unacceptable morbidity and mortality. Only after the landmark work of Kocher, the technical principles of thyroidectomy were solidly established, and are still valid nowadays.

METHODS

Revision article on practical suggestions to decrease morbidity associated with thyroidectomy, as well as warning against common pitfalls that the surgeon may encounter.

RESULTS

The following subjects are objectively addressed: how to manage upper airway obstruction, how to avoid non-esthetic scars and how to recognize the most prevalent anatomic variations concerning the recurrent nerve, the external branch of the superior laryngeal nerve and the parathyroid glands, in order to decrease operative morbidity.

CONCLUSION

The Head and Neck Surgeon must be fully aware of the complex anatomy of the central visceral compartment of the neck, as well as must be prepared to handle some complications of thyroidectomy that can be life-threatening.

The Scintigraphic Appearance of Subcapsular Parathyroid Adenomas

PURPOSE

Approximately 5 to 10% of parathyroid adenomas are located within the thin, fibrous capsule of the thyroid gland. These subcapsular adenomas can complicate minimally invasive parathyroidectomy. The small incision used in this procedure limits the view of the surgical bed. Palpation is less sensitive when the adenoma is covered by the thyroid capsule. If a subcapsular parathyroid adenoma can be identified on preoperative parathyroid scintigraphy, nuclear medicine physicians can recommend exploration of the thyroid capsule early, leading to an easier, more efficient operation. The objective of this observational study was to identify the scintigraphic appearance of subcapsular parathyroid adenomas.

MATERIALS AND METHODS

A total of 109 patients with primary hyperparathyroidism underwent preoperative dual-phase Tc-99m sestamibi parathyroid scintigraphy at our tertiary care center from October 2002 to March 2004. Tc-99m pertechnetate was used as a supplemental technique when deemed necessary for optimal interpretation. Retrospective chart review identified 16 surgically proved subcapsular parathyroid adenomas. Parathyroid scintigraphy was reviewed.

RESULTS

Subcapsular parathyroid adenomas tend to conform to the expected shape of the thyroid gland. In this small series, subcapsular parathyroid adenomas followed 1 of 3 patterns on lateral images: (1) focal convex distortion of the posterior wall of the thyroid, (2) polar lentiform configuration, and (3) compression of the posterior thyroid parenchyma.

CONCLUSION

Subcapsular parathyroid adenomas often have a distinct appearance on scintigraphy. Preoperative identification of this type of parathyroid adenoma can direct a subcapsular surgical approach, optimizing the efficiency of the minimally invasive parathyroidectomy.

Re-operation for hyperparathyroidism

INTRODUCTION

Re-operation for hyperparathyroidism (HPT) represents a challenge for experienced endocrine surgeons. The present study reviews the technical and pathological factors for failure of initial surgery and identifies strategies to approach re-operative parathyroidectomy.

METHODS

Clinical details, operation notes, pathology, localization studies and complications for re-operative cases performed by three surgeons were reviewed.

RESULTS

Over a 10-year period there were 40 re-operative cases with a 98% success rate. There were 31 patients with primary HPT, 21 with persistent primary (PP) and 10 with recurrent primary (RP). Multigland disease (MGD) was present in 19 of the 31 (61%) primary HPT cases. The culprit gland was ectopic in 14 cases, at a normal location in 10 and there was regrowth at previously excised sites or remnant disease in 10. There were nine patients with secondary HPT, four with persistent secondary (PS) and five with recurrent secondary (RS). The culprit gland was ectopic in five, at a normal location in four and regrowth at a previously excised site in two. Pre-operative investigations were employed in all cases and the most helpful were sestamibi scan (S) and selective venous sampling (SVS) for parathyroid hormone (PTH) concentration. True positive localizations for S was in 20 of 34 cases (59%), SVS in seven of nine (78%), computed tomography (CT) in seven of 17 (41%) and ultrasound scan (USS) in 10 of 28 (36%).

CONCLUSIONS

Re-operative parathyroidectomy can be performed by experienced surgeons with a very high success rate and minimal complications.

[Intrathyroidal parathyroid adenoma. Study of a case]

Intrathyroidal parathyroid adenoma is an infrequent lesion which can be explained by abnormalities during embryonic migration of the parathyroid glands. That abnormality can be a cause of failed cervical exploration for primary hyperparathyroidism. From a case report and literature data, we propose an exploration processes to search those ectopic parathyroid adenoma.

Unintentional parathyroidectomy during thyroidectomy

OBJECTIVES

In the United States thyroidectomy is a frequently performed surgery by both general and head and neck surgeons. Even the most experienced thyroid surgeon, however, has probably received a pathology report stating that an incidental parathyroid gland or parathyroid tissue was found in the submitted thyroidectomy specimen. The aim of this report is to explore some of the pathologic and clinical characteristics of unintentional parathyroidectomy during thyroidectomy.

STUDY DESIGN

A retrospective review was performed of thyroidectomies performed at the University of California, Los Angeles, Center for the Health Sciences between 1989 and June 1998 which had pathology reports showing parathyroid tissue contained within the thyroidectomy specimen. This excluded any tissue submitted separately to be evaluated for parathyroid tissue and parathyroid tissue removed unintentionally during a thyroidectomy for a different procedure such as a laryngectomy or surgery for parathyroid disease.

METHODS

The pathology slides were reviewed to determine the incidence of unintentional parathyroid tissue removal, the size of the parathyroid tissue found within the thyroid specimen, the location of the parathyroid tissue (extracapsular, intracapsular, intrathyroidal), and whether this unintentional parathyroidectomy during thyroidectomy caused clinical consequences.

RESULTS

Four hundred fourteen applicable thyroidectomies were performed during this time with 45 (11%) discovered cases of unintentional parathyroidectomy during thyroidectomy. Twenty-five (56%) cases were discovered during thyroidectomy for benign disease, and 20 (44%) during thyroidectomy for malignant thyroid disease. All the parathyroid tissue was normal and was found in extracapsular (58%), intracapsular (20%), or intrathyroidal (22%) locations. Of these 45 cases, recurrent laryngeal nerve paralysis was found only in two patients who had the nerve resected intentionally during the thyroidectomy, and none of the patients developed permanent hypocalcemia.

CONCLUSIONS

Incidental parathyroid gland tissue was reported in 11% of the thyroidectomies performed in our series, without the clinical consequence of hypocalcemia. The majority (78%) of this parathyroid tissue was found in the extracapsular and intracapsular locations; therefore it is possible that these parathyroid glands may be identified and preserved with more meticulous inspection of the thyroid capsule during and after thyroidectomy to decrease the incidence of unintentional parathyroidectomy during thyroidectomy in the future.

Minimal-access parathyroid surgery using intraoperative parathyroid hormone assay

OBJECTIVES

Review the most current preoperative localization imaging techniques in patients with primary hyperparathyroidism and demonstrate their applicability to targeted tumor removal with intraoperative parathyroid hormone (PTH) monitoring.

STUDY DESIGN

Retrospective review of 40 consecutive patients undergoing parathyroid surgery with intraoperative PTH assay as the principal determinant of correction of the hyperparathyroid state. Details of the technology, cost analysis, and comparison with other management methods are discussed.

METHODS

The standard intact PTH chemiluminescent assay (Nichols Diagnostics) and modifications to allow accelerated intraoperative results are discussed in detail. The time intervals between completion of parathyroid excision and postremoval assay and subsequent laboratory investigation present a practical therapeutic algorithm.

RESULTS

Forty consecutive patients with hyperparathyroidism were treated surgically with intraoperative PTH as the determinant of satisfactory resolution of the disease state. In most instances, the surgical field was reduced to the targeted pathology identified by preoperative localization, and all patients became eucalcemic when this method was employed. Approximately half of eligible patients were treated under local anesthesia.

CONCLUSIONS

Intraoperative PTH assay has added a new dimension to primary and revision parathyroid surgery. It is cost-effective and accurate and may reduce the morbidity of surgical intervention in revision procedures.