Functioning oxyphil cell adenomas of the parathyroid gland. A study of 15 cases

Histopathological Features of Parathyroid Adenoma and 18F-Choline Uptake in PET/MR of Primary Hyperparathyroidism

BACKGROUND

The aim of this study was to assess the relationship between the histopathological properties of hyperfunctioning parathyroids and parathyroid 18F-choline uptake.

PATIENTS AND METHODS

A total of 31 parathyroid adenomas were retrospectively analyzed in patients with primary hyperparathyroidism and preoperative 18F-choline PET/MR. PET/MR parameters of parathyroid glands (SUVmax and target-to-background ratio in early-phase [EP] and late-phase [LP]), MRI volume, preoperative parathyroid hormone (PTH) serum concentration, and postoperative histopathology (predominant cell type and growth pattern of adenoma cells, location and size of adenoma) were assessed. The relationship of PET/MR parameters, PTH, and histological parameters was determined using linear regression, Spearman correlation and Kruskal-Wallis test.

RESULTS

The median volume of parathyroid adenoma was 421.78 ± 142.46 mm3 (46.39-4412.69). Adenomas were predominantly composed of chief, water-clear, and oncocytic/oxyphilic cells in 27/31, 2/31, and 2/31 cases, respectively. The growth pattern was predominantly solid, follicular, and trabecular in 18/31, 8/31, and 5/31, respectively. The SUVmax was 6.71 ± 3.39 in EP and 6.91 ± 3.97 in LP. Follicular growth pattern had slightly higher EP SUVmax (trabecular: 4.12 ± 0.56; solid: 6.62 ± 3.19; follicular: 8.56 ± 3.96; P = 0.046). Spearman correlation showed strong positive correlation between volume and both EP and LP SUVmax (0.626; P = 0.0001 and 0.576; P = 0.0001, respectively). Linear regression analysis revealed significant correlation between PTH level and EP and LP SUVmax (both P = 0.001); in contrast, no correlation was found between PTH level and both cell type and growth pattern.

CONCLUSIONS

Our findings suggest that 18F-choline uptake of parathyroid adenomas might be associated both with the histological growth pattern and adenoma volume, but not with a specific cell type.

Oxyphil cells in primary hyperparathyroidism: a clinicopathological study

BACKGROUND

The role of oxyphil cells (OxC) in primary hyperparathyroidism (PHPT) still remains controversial. Historically, they were believed to be involuted cells. However, they could play an important role in hormone secretion. The clinical behavior of OxC-rich adenomas and preoperative PHPT localization tests have been widely studied. The aim of this study is to analyze the implications of OxC in PHTP.

METHODS

A retrospective cohort study of patients undergoing parathyroidectomy for PHPT was conducted. Additionally, we included normal glands removed in the context of PHPT or inadvertently during a thyroidectomy. All glands were reviewed independently by three researchers, performing a semi-quantitative analysis of the percentage of OxC. Groups with < 25% OxC and > 75% OxC were compared.

RESULTS

In the period 2010-2017, 238 patients and 261 removed glands were included (8.8% OxCA > 75%). There were no differences in symptomatology and levels of preoperative calcium, parathormone, or 25-OH vitamin. Patients with OxCA > 75% had worse preoperative glomerular filtration rate (81.2 vs. 69.7 mL/min/1.73 m²; p = 0.043). They also had a trend towards larger size and weight (17 vs. 20 mm, p = 0.135 and 562 vs. 875 mg, p = 0.495), while ultrasound was found to have better accuracy (48.3% vs. 73.7%; p = 0.035). There were no normal glands with a content of OxC > 75%.

CONCLUSIONS

Our study suggests that phosphocalcic metabolism is not influenced by the presence of a high content of OxC in the parathyroid glands. A high content of OxC seems to be exclusive to pathologic glands and could be related to the deterioration of renal function in patients with PHPT.

Choline PET/CT in parathyroid imaging: a systematic review

One of the most promising imaging techniques in primary hyperparathyroidism is PET/CT with choline-based tracers. To investigate the current evidence of these tracers in localizing parathyroid adenoma, a systematic review was performed. A comprehensive literature search was carried out and eligible studies were analyzed. Data were extracted, the level of evidence was scored, and performance data were pooled to calculate the weighted detection rate. Eleven articles were included in this study. The pooled detection rate was 97 and 94% on per patient-based and per lesion-based analysis, respectively. There was considerable heterogeneity between studies and the level of evidence was determined to be 3a-, following Oxford criteria. Choline PET/CT has shown favorable results in detection of hyperfunctioning parathyroid tissue and may replace conventional technetium-99m-sestamibi scintigraphy in preoperative planning of parathyroid surgery. However, the quality of current evidence is moderate, and additional high-quality studies are needed to confirm these numbers.

Molecular profiles of oxyphilic and chief cell parathyroid adenoma

CONTEXT

Parathyroid adenomas may be composed of chief cells (conventional or water-clear), oxyphilic cells or a mixture of both cells. The molecular background is rarely studied.

OBJECTIVE

To molecularly characterize parathyroid adenomas of different cell type composition.

DESIGN

Chief and oxyphilic cell adenomas were compared in a cohort of 664 sporadic cases. Extensive analyses of parathyroid tissues were performed in subgroup. Gene expressions of known parathyroid-related genes were quantified by qRT-PCR. Protein expression profiles determined by liquid chromatography - tandem mass spectrometry (LC-MS/MS) were compared between each type of parathyroid adenomas. Selected proteins were analysed by Western blot and immunohistochemistry.

RESULTS

Patients with oxyphilic cell adenoma were found to be older at the time of operation than chief cell adenoma cases but did not differ in gender, serum calcium or tumor weight. The gene expression of CASR, VDR, FGFR1, CYP27B1, CYP24A1, PTHLH, GCM2, NDUFA13, CDKN1B, MEN1 and CNND1 did not differ between the groups. VDR protein levels were weaker in oxyphilic adenomas. The proteomic studies identified a set of novel dysregulated proteins of interest such as nuclear receptor subfamily 2 group C member 2 (TR4), LIM domain only protein 3 (LMO3) and calcium-binding protein B (S100B). LMO3 and S100B showed higher expression in oxyphilic adenoma and may be involve in parathyroid tumorgenesis through the p53 pathway. TR4 showed different subcellular localisation between adenoma and normal rim.

CONCLUSION

Chief and oxyphilic cell parathyroid adenomas have partly overlapping but also distinct molecular profiles. The calmodulin-eEF2K, TR4 and p53 pathways may be involved in the tumor development.

Functioning oxyphil parathyroid adenoma: a case report

Oxyphil parathyroid adenomas are rare and clinical features of patients with this entity are not well defined. We are presenting a case of primary hyperparathyroidism with marked elevation of parathyroid hormone (PTH) and near normal calcium levels, that underwent parathyroidectomy. Histopathology revealed an oxyphil adenoma which showed positivity for PTH on immunohistochemical staining. Post - operatively, there was a significant decline in both PTH and alkaline phosphatase levels. Benign oxyphil adenomas may mimic parathyroid carcinomas, both in terms of clinical features and tumour size; and they should be considered in the differential diagnosis of patients with primary hyperparathyroidism.

Oncocytic lesions of the neuroendocrine system

This paper reviews the pathologic features of lesions which are oncocytic and involve classic endocrine organs. The history of the oncocytic cell, its morphologic and ultrastructural features, and important immunohistochemical findings are reviewed. Oncocytic proliferations including non-neoplastic and neoplastic of the thyroid, parathyroid, adrenal (both cortex and medulla), and pituitary are described. Their clinical relevance, functional capacity and capability, and where appropriate, prognostic implications are discussed. Important and relevant molecular biological information is included where appropriate.

Aryl hydrocarbon receptor interacting protein (AIP) mutations occur rarely in sporadic parathyroid adenomas

CONTEXT

The molecular pathogenesis of primary hyperparathyroidism is still largely unknown. The aryl hydrocarbon receptor interacting protein (AIP) gene has a major role in the pathogenesis of familial isolated pituitary adenoma.

OBJECTIVE

We evaluated the involvement of the AIP gene in sporadic parathyroid adenomas.

PATIENTS AND DESIGN

We performed direct sequencing and multiplex ligation-dependent probe amplification analyses of the AIP gene in a large series of sporadic parathyroid adenomas. Loss of heterozygosity (LOH) at the AIP locus was studied, and aryl hydrocarbon receptor interacting protein immunostaining was also performed. In addition, alterations in the MEN1 gene were studied.

RESULTS

A somatic AIP mutation, substitution of arginine with glutamine at codon 304 (R304Q), was identified in 2 of 132 tumors. The mutation was germline in both cases despite the nonfamilial presentation. Heterozygous AIP large deletions were detected in 29 cases including 1 of the 2 mutated tumors, confirming a biallelic inactivation of the AIP gene. The AIP-mutated tumor with LOH showed decreased AIP immunostaining compared with normal parathyroid. LOH at the MEN1 locus, which often shared LOH at the AIP locus, was found in one third of tumors. Somatic MEN1 mutations were found in the 1 of the 2 AIP-mutated tumors and in 22 parathyroid adenomas. In addition, multiplex ligation-dependent probe amplification analysis revealed 1 large deletion of the MEN1 gene in 1 patient.

CONCLUSIONS

The AIP gene is rarely involved in parathyroid adenomas, but the germline nature of the mutations suggests that it might predispose to primary hyperparathyroidism. MEN1 gene alterations occur in a substantial proportion of sporadic parathyroid adenomas.

Oncocytic mania: a review of oncocytic lesions throughout the body

Oncocytic lesions are characterized pathologically by an abundance of oncocytes, that is by enlarged, eosinophilic, and finely granular cells enriched in mitochondria. They can arise in numerous organs and tissues, often in endocrine glands, and have been associated with hyperplasia, autoimmunity, and neoplasia. The causes and mechanisms that transform a normal cell into an oncocyte remain to be elucidated. Aim of this article is to review the most common oncocytic lesions, highlighting their key pathological features and clinical significance.

Directed parathyroid exploration: Evolution and evaluation of this approach in a single-institution review of 346 patients

OBJECTIVES/HYPOTHESIS

Critical evaluation of a directed exploration protocol used by a single surgeon in the management of surgical parathyroid disease.

STUDY DESIGN

Retrospective chart review was made of patients surgically managed for hyperparathyroidism at an academic tertiary care center.

METHODS

Three hundred forty-six patients were evaluated for biochemically proven hyperparathyroidism between March 1995 and February 2002. A directed exploration protocol was implemented in appropriately selected patients with primary hyperparathyroidism and in patients with secondary or tertiary hyperparathyroidism requiring repeat operation. The protocol included preoperative technetium-99m sestamibi imaging for hyperfunctional parathyroid localization, targeted neck exploration, rapid intraoperative parathyroid hormone determination, and limited-stay discharge from the ambulatory surgical recovery unit. Data collection was accomplished by entering patient evaluation, management, and outcome information prospectively into collective case report forms. A retrospective analysis of the data was conducted for the purpose of evaluating the effectiveness of the protocol.

RESULTS

Sustained normocalcemia beyond 6 months postoperatively was achieved in 323 of 327 (99%) patients with primary hyperparathyroidism. Eighty-four percent (84%) of patients with secondary or tertiary hyperparathyroidism achieved normocalcemia or had resolution of symptoms as a measure of therapeutic success. The complication rate for the entire series of patients was 2.8%. Ninety-two percent of positive findings on sestamibi scan correctly predicted the location of an adenoma, whereas a negative finding accurately predicted the absence of an enlarged gland in a "usual" location in 81% of patients. Twenty-six patients (9%) had a false-positive finding on the scan, whereby a solitary adenoma was found contralateral to the side indicated by the scan. Overall, the positive predictive value for sestamibi imaging in the series was 91%. Intraoperative parathyroid hormone determination yielded an overall rate of reduction of 80% from preoperative levels during directed exploration. Sustained normocalcemia was achieved in all patients in whom intraoperative parathyroid hormone determination demonstrated a minimum decline of 50% from preoperative levels following resection of hyperfunctional parathyroid tissue (adenoma[s]). The majority (72%) of patients were managed in an outpatient (ambulatory surgery) setting and were discharged to home within 8 to 12 hours after surgery.

CONCLUSION

The directed exploration protocol for surgical management of hyperparathyroidism generated surgical rates of success that were as good as and, in most cases, improved over that of traditional bilateral exploration. This achievement was associated with low morbidity and reduced time and facility utilization, conveying improved cost-effectiveness. This surgical strategy should serve to enhance the capability of the surgeon to safely and efficiently manage the majority of patients with surgical parathyroid disease.

[Functioning oxyphil cell adenoma of parathyroid diagnosed with ureteral stone]

A case of oxyphil cell adenoma of parathyroid is presented. A 82-year-old woman complained of back pain. Left hydronephrosis, elevated serum calcium-parathyroid hormone and a nodule in the right neck suggested functioning parathyroid adenoma. Resected adenoma (15 mm x 10 mm x 5 mm) was exclusively composed of oxyphil cell. Production of parathyroid hormone by oxyphil cells was confirmed by immunohistochemistry. This case was found to be the smallest parathyroid oxyphil cell adenoma hitherto reported that caused urolithiasis.

Substernal oxyphil parathyroid adenoma producing PTHrP with hypercalcemia and normal PTH level

Background

Parathyroid adenoma is the most common cause of primary hyperparathyroidism. Preoperative serum calcium and intact-parathyroid hormone levels are the most useful diagnostic parameters that allow differentiating primary hyperparathyroidism from non-parathyroid-dependent hypercalcemia. Parathyroidectomy is the definitive treatment for primary hyperparathyroidism. Approximately 5% of patients who underwent parathyroidectomy present with persistent or recurrent hyperparathyroidism due to ectopic localization of the adenoma. Functioning oxyphil parathyroid adenoma is an uncommon histological form, seldom causing primary hyperparathyroidism. Parathyroid adenoma with hypercalcemia exhibiting normal parathyroid hormone level is rare. An incidence of 5% to 33% has been documented in the literature; no etiologic explanation has been given. In 1987, parathyroid-hormone-related peptide was isolated as a causative factor of humeral hypercalcemia of malignancy. The presence of parathyroid-hormone-related peptide in parathyroid tissue under normal and pathological conditions has been described in the literature; however, its role in causing hyperparathyroidism has not yet been defined.

Case presentation

We present a case of persistent hypercalcemia with a normal level of intact-parathyroid hormone due to a substernal parathyroid adenoma, treated with radioguided parathyroidectomy. The final histological diagnosis was oxyphil adenoma, positive for parathyroid-hormone-related peptide antigens.

Conclusion

In clinical practice, this atypical biochemical presentation of primary hyperparathyroidism should be considered in the differential diagnosis of hypercalcemia. The parathyroid-hormone-related peptide should be considered not only in the presence of malignancy.

Parathyroid lipoadenomas: a rare cause of primary hyperparathyroidism

OBJECTIVE

To review one institution's experience with parathyroid lipoadenomas and to report the associated clinical characteristics.

METHODS

We present a case series of parathyroid lipoadenomas. A parathyroid lipoadenoma was defined as a single adenoma with more than 50% fat on histologic examination in conjunction with primary hyperparathyroidism and resolution of hypercalcemia postoperatively. Patients who fulfilled the diagnostic criteria were identified from the surgical pathology files of the Mayo Clinic.

RESULTS

Five cases of parathyroid lipoadenomas, including 1 oxyphil lipoadenoma, were identified during the period from 1971 to 2001. The clinical picture of the study subjects resembled that of a typical patient with primary hyperparathyroidism. Parathyroid lipoadenomas were identified in 3 women (60%) and 2 men (40%), and only 1 patient presented with possible hypercalcemia-related symptoms of nephrolithiasis and hip fracture, leading to diagnosis. The mean serum calcium concentration was 11.1 mg/dL. Preoperatively, all study subjects had elevation of serum parathyroid hormone levels. Two of 3 patients (67%) had the tumor identified preoperatively by neck ultrasonography.

CONCLUSION

A parathyroid lipoadenoma is a rare cause of primary hyperparathyroidism. The clinical features of this pathologic entity are similar to those of the more common pathologic variants of parathyroid disease associated with primary hyperparathyroidism.

Oxyphil parathyroid adenoma: a malignant presentation of a benign disease

Functioning parathyroid adenomas of the oxyphil cell type are rare, and the clinical characteristics of patients with these tumors have not been well defined. We describe two cases of severe primary hyperparathyroidism (PHPT) caused by benign oxyphil parathyroid adenomas. The patients' clinical presentations mimicked parathyroid carcinoma. Both had very large tumors associated with marked elevations in PTH and serum calcium levels. Skeletal manifestations were also atypical for benign PHPT, with severe osteoporosis in one patient and osteitis fibrosa cystica in the other. These cases also highlight the remarkable capacity of the skeleton to recover after successful parathyroidectomy, previously reported in other forms of severe PHPT. Bone mineral density improved dramatically 1 yr after parathyroidectomy, with increases of 51% at the lumbar spine, 36% at the total hip, and 11% at the distal one third radius. Most of the increases occurred in the first postoperative months. Consistent with this early and accelerated skeletal response, markers of bone turnover were increased 2 months after surgery and normalized by 8 months postoperatively. In patients with PHPT who present with severe or atypical clinical features, oxyphil adenoma should be considered.

Metachronous Double Parathyroid Adenomas Involving Two Different Cell Types: Chief Cell and Oxyphil Cell

OBJECTIVE

To describe a patient with the rare occurrence of metachronous double parathyroid adenomas involving two different cell types.

METHODS

We present a case report and a summary of the related literature.

RESULTS

Double parathyroid adenomas are rare, occurring in 1.7 to 9% of patients with primary hyperparathyroidism. Most double parathyroid adenomas are synchronous lesions; few metachronous double parathyroid adenomas have previously been reported. Most parathyroid adenomas are of the chief cell variety, with oxyphil cell adenomas occurring in less than 1% of cases. In a 73-year-old man with no prior history or known family history of endocrine disease, primary hyperparathyroidism developed, and cervical ultrasonography demonstrated a mass in the right side of the neck. Subsequent parathyroidectomy revealed a right superior chief cell adenoma. Postoperatively, the patient's parathyroid hormone and serum calcium levels returned to normal and remained so for at least 9 years. Twelve years after the first operation, recurrent hyperparathyroidism prompted repeated surgical exploration of the neck, which disclosed a large left superior parathyroid mass. Surgical excision and histologic examination revealed the lesion to be an oxyphil cell adenoma.

CONCLUSION

To our knowledge, this is the first reported case of metachronous double parathyroid adenomas involving two different cell types: chief cell and oxyphil cell.

Oxyphil parathyroid carcinomas: a clinicopathologic and immunohistochemical study of 10 cases

Oxyphil parathyroid carcinomas are uncommon neoplasms, and the clinicopathologic features of these tumors are largely unknown. We evaluated the clinicopathologic features of oxyphil parathyroid carcinomas and the expression of cytokeratin 14 (CK14), the high-affinity glucose transporter-4 (Glut-4), as well as the cell cycle proteins p27 and Ki67 and compared these with oxyphil parathyroid adenomas and chief cell parathyroid adenomas and carcinomas. Formalin-fixed, paraffin-embedded archival tissues from primary (n = 6) and recurrent (n = 4) oxyphil carcinomas were analyzed and compared with chief cell parathyroid carcinomas (n = 12), oxyphil parathyroid adenomas (n = 38), and chief cell parathyroid adenomas (n = 17) by immunohistochemistry for CK14, Glut-4, p27, and Ki67 using the avidin-biotin peroxidase system. Patients with primary oxyphil and chief cell carcinoma presented with high levels of serum calcium (n = 15.5 and 13.7 mg/dL, respectively). Approximately half the patients in each group died of disease. The Ki67 labeling index was higher (4.9 vs 1.9) and the p27 index lower (23 vs 66) in primary oxyphil carcinoma compared with primary oxyphil adenomas. CK14 was expressed in most oxyphil adenomas (35 of 38 cases) but not in oxyphil carcinomas (0 of 10 cases). Glut-4 was more commonly expressed in both groups of adenomas compared with carcinomas. These results show that oxyphil parathyroid carcinomas are functional malignancies similar to chief cell carcinomas and are associated with hypercalcemia, recurrence, and death. Expression of CK14 is very different in oxyphil adenomas compared with carcinomas. Although distinction between parathyroid adenomas and carcinomas can only be made by histopathologic and clinical findings, these results suggest that immunostaining for CK14, p27, and Ki67 may provide additional information to help distinguish between difficult cases of parathyroid adenomas and carcinomas. These findings also indicate that the same histopathologic features should be used to diagnose oxyphil and chief cell parathyroid carcinomas.

Ultrastructure of human parathyroid cells in health and disease

Parathyroid glands (n = 271) removed from 130 patients were examined by light and electron microscopy. A standardized method of tissue processing was employed and morphometry was performed. The aim of the paper is to provide a description of the human parathyroid chief cell ultrastructure in health and disease, with quantitative evaluation of structures involved in secretion of parathyroid hormone in a large case series, and to discuss their role in current diagnostic histopathology. The patients were euparathyroid (n = 10), or affected by primary (n = 97), secondary (n = 8), or tertiary (n = 15) hyperparathyroidism. In normal glands, solid parenchyma was composed of chief cells, large clear cells, transitional-oxyphil cells, and oxyphil cells. Chief cell hyperplasia, pseudo-adenomatous hyperplasia, adenoma, water-clear cell hyperplasia, and carcinoma were the most usual forms of parathyroid disease responsible for primary hyperparathyroidism. In chief cell hyperplasia, all the parathyroid glands were enlarged and the chief cells were in an active state of hormone secretion, with a large Golgi complex, abundant rough endoplasmic reticulum (RER), small lipid droplets, and tortuous plasma membrane. In pseudo-adenomatous hyperplasia, one gland was enlarged and the others displayed a normal size; however, electron microscopic examination and morphometric analysis showed that all the glands had active cells. Adenomas displayed a pattern similar to those of pseudo-adenomatous hyperplasia, with one gland enlarged and the others of normal size. However, ultrastructural examination and morphometry showed that the normal-size glands were hypo-active. Water-clear cell hyperplasia showed cells filled with cytoplasmic vacuoles. In these cells, structures with intermediate features between secretory granules and vacuoles were visible. Nucleo-cytoplasmic atypias were frequently visible in parathyroid carcinoma cells. In secondary and tertiary hyperplasia, active chief cells were regularly mixed with oxyphil or transitional-oxyphil cells. The tertiary hyperplasia was characterized by RER-associated structures that were not found in the normal or other pathological conditions. These results demonstrate that electron microscopy and morphometry represent useful tools in parathyroid histopathology.

An unusual case of synchronous thyroid and parathyroid adenomas

A 52-year-old woman was evaluated for an enlarging neck mass. Fine-needle aspirate contained Hürthle cells and thyroidectomy revealed two separate thyroid morphologically similar lesions. Immunohistochemical studies confirmed diagnoses of separate Hürthle cell thyroid and oxyphil parathyroid adenomas. Diagnostic pitfalls and the role of immunohistochemistry in diagnosis are discussed.

The role of the pathologist in diagnosis and surgical decision making in hyperparathyroidism

Hyperparathyroidism has been diagnosed with increasing frequency in recent decades. The concomitant awareness that the disease may be the cause of a concealed morbidity and even an increased mortality has resulted in more liberal indications for surgery. Many patients currently undergo surgery on the grounds of only mild hypercalcemia and in the absence of any apparent clinical symptoms. This policy of early surgical treatment has emphasized the importance of a histopathological parathyroid diagnosis, since many of these patients exhibit chief cell hyperplasia and minimal glandular enlargement. Light microscopic examination of frozen sections stained with hematoxylin-eosin and with stains for demonstration of cytoplasmic fat in the parathyroid chief cells, and appropriate weight estimates of the parathyroid glands, constitute the conventional, intra-operative basis for the diagnosis. The use of specific antiparathyroid antibodies is an important new tool in the histopathological parathyroid examination, mainly because of the ability to demonstrate the cause of increased parathyroid hormone release from the pathological parathyroid tissue. A careful histopathological examination in combination with gross inspection of the parathyroid glands by an experienced eye should contribute to adequate surgical treatment and minimize errors in operative management in patients with hyperparathyroidism.