Parathyroid Specimens Research Articles

Role of thymectomy in surgical treatment of renal hyperparathyroidism

IntroductionThe role for routine thymectomy in patients with secondary or tertiary hyperparathyroidism (SHPT, THPT) is unclear. We aim to compare rates of recurrence and complications in patients who underwent subtotal parathyroidectomy with and without thymectomy. MethodsPatients who underwent surgery for renal HPT at a tertiary endocrine surgery center between 2010 and 2022 were reviewed. Presence of parathyroid tissue in resected tissue was identified through pathology reports. A multivariate logistic regression was used to compare baseline characteristics, recurrence rates and complications between those who did and did not undergo thymectomy. ResultsOf 107 patients who underwent subtotal parathyroidectomy, 29 (27.1 ​%) underwent concomitant thymectomy. Recurrence occurred in 15 patients (14 ​%). Thymectomy did not affect recurrence (OR: 0.33, 95%CI: 0.06–1.28, p ​= ​0.14), but was associated with permanent hypoparathyroidism (OR: 4.62, 95%CI: 1.67–13.18, p ​= ​0.003). Fewer parathyroid specimens increased the odds of thymectomy (p ​= ​0.04). Parathyroid glands were found in 6 thymectomy samples (20.7 ​%). ConclusionThymectomy at the time of subtotal parathyroidectomy for renal HPT was not associated with disease recurrence, but increased likelihood of permanent hypoparathyroidism.

Expression of the Calcium-Sensing Receptor on Normal and Abnormal Parathyroid and Thyroid Tissue

IntroductionCurrent imaging techniques have several limitations in detecting parathyroid glands. We have investigated the calcium-sensing receptor (CaSR) as a potential target for specifically labeling parathyroid glands for radiologic detection. For accurate imaging it is vital that a large differential expression exists between the target tissue and adjacent structures. We sought to investigate the relative abundance of the CaSR in normal and abnormal parathyroid tissue, as well as normal and abnormal thyroid. MethodsExisting clinical specimens were selected that represented a wide variety of pathologically and clinically confirmed malignant and benign thyroid and parathyroid specimens. Sections were stained for the CaSR using immunohistochemistry and scored for intensity and abundance of expression. (H score = intensity scored from 0 to 3 multiplied by the % of cells at each intensity. Range 0-300). ResultsAll parathyroid specimens expressed the CaSR to a high degree. Normal parathyroid had the highest H score (271, s.d. 25.4). Abnormal parathyroid specimens were slightly lower but still much higher than normal thyroid (H score 38.3, s.d. 23.3). Medullary thyroid cancer also expressed the CaSR significantly higher than normal thyroid (H score 182, s.d. 69.1, P < 0.001) but below parathyroid levels. Hürthle cell carcinoma expressed the CaSR to a lesser degree but higher than normal thyroid (H score 101, s.d. 46.4, P = 0.0037). ConclusionsThe CaSR is differentially expressed on parathyroid tissue making it a feasible target for parathyroid imaging. False positives might be anticipated with medullary and Hürthle cell cancers.

US Features of the Parathyroid Glands: An Intraoperative Surgical Specimen Study.

This study aimed to evaluate the US features of the parathyroid glands (PTGs) using surgical specimens of normal PTGs obtained during thyroid surgery. This study included 34 normal PTGs from 17 consecutive patients who underwent thyroid surgery between December 2020 and March 2021. All normal PTGs were histologically confirmed by intraoperative frozen-section biopsy for autotransplantation. Surgically resected parathyroid specimens were scanned in sterile normal saline using high-resolution US prior to autotransplantation. The US features of echogenicity (hyperechogenicity or hypoechogenicity), echotexture (homogeneous or heterogeneous), size, and shape (ovoid or round) were retrospectively evaluated. The echogenicity of the three PTGs was compared with that of the thyroid parenchyma of the resected thyroid specimens in two patients. All PTGs showed hyperechogenicity similar to that of gauze soaked in normal saline. Homogeneous hyperechogenicity was observed in 32/34 (94.1%) patients, and the echogenicity of the three PTGs was hyperechoic compared with that of the thyroid parenchyma. The long diameter of the PTGs ranged from 5.1 mm to 9.8 mm (mean, 7.1 mm) and the shape of the PTGs was ovoid in 33/34 (97.1%) patients. The echogenicity of normal PTG specimens was consistently hyperechoic, and the small ovoid homogeneously hyperechoic structure was a characteristic US feature of the PTGs.

Surgical management of secondary hyperparathyroidism in dialysis patients in Senegal.

Secondary hyperparathyroidism (SHPT) is a common complication of end-stage renal disease. Surgical management occurs in severe forms and/or unresponsive medical treatment. The aim of this study was to outline the indications of parathyroidectomy and its evolution after surgical approach. It was a five-year multicenter backward study in Otorhinolaryngology Department of Fann Hospital and four dialysis centers in Dakar. We include all patients with SHPT who underwent surgery. Preoperative clinical and paraclinical parameters, clinical-biological evolution, and histology findings of the resected parathyroid specimen were collected. Out of 58 patients with hyperparathyroidism, 18 patients required parathyroidectomy, corresponding to a prevalence of 31%. Mean age of patients was 46.6 ± 15.29 years and sex ratio 0.61. Mean duration on dialysis was 44.4 ± 30 months. Ten patients (55.56%) had bone pain and nine patients (50%) had joint pain. Mean serum calcium was 97.27 ± 8.66 mg/L. Mean blood phosphorus levels were 40.47 ± 9.99 mg/L. Mean iPTH rate was 1493.22 ± 1014.93 ng/mL, with a maximum of 5000 ng/mL (77N). Mean value of 25-OH Vitamin D was 32.89 ± 16.02 ng/mL. Parathyroidectomy was indicated after failure of medical treatment with persistence of a serum intact parathyroid hormone concentration above 800 μg/mL in all patients. Subtotal parathyroidectomy (7/8) was performed in 11 patients (61.1%). Two patients (11.11%) benefited from a selective parathyroidectomy (3/4). Evolution was favorable for 13 patients, corresponding to a success rate of 72.2%. It was unfavorable in five patients including one patient with hypoparathyroidism and four patients with recurrent hyperparathyroidism. Surgery for patients with renal hyperparathyroidism in the era of calcimimetics continues to play an important role in selected patients and achieves efficient control of hyperparathyroidism in developing countries.

Comparative analysis of clinicopathologic features between adenoma and hyperplasia in surgically treated patients for hyperparathyroidism: A retrospective study

BackgroundHyperparathyroidism (HPT) is a common endocrine disorder resulting from overproduction of parathyroid hormone (PTH). Usually HPT is caused by parathyroid adenoma (PA) or parathyroid hyperplasia (PH). Our aim is to assess clinicopathologic features associated with PA and PH in patients with HPT. MethodsWe retrospectively collected 29 cases of HPT recorded at the Department of Pathology of Hassan II University Hospital of Fes, Morocco, from 2013 to 2016. ResultsThe mean age was 52.14 ± 15.7 years (range of 22–76 years), 13 patients (44.8%) had primary HPT, 16 (55.2%) had secondary HPT. The largest size of the resected parathyroid specimens ranged from 1 to 3.6 cm (mean of 2.26 ± 0.66 cm). Seventeen patients (58.6%) had PA, the remaining cases were diagnosed as PH. There were no significant statistical differences between PA and PH in age, sex, clinical presentation, preoperative serum PTH, or in parathyroid gland size (P > 0.05). However compared to PH, PA is more often a single-gland disease, found in primary HPT with higher preoperative calcium level (P ˂ 0.05). ConclusionsIn patients surgically treated for HPT, PA is associated with some distinctive clinicopathologic features. These findings could be helpful to pathologists and clinicians for appropriate clinicopathologic management.

Comparative Transcriptomic Profiling Revealed Distinctive Patterns in Differentially Expressed Genes Related to Clinicopathologic Features of Parathyroid Carcinoma and Adenoma

Parathyroid carcinoma is a rare malignancy which remains as a clinical unmet need lacking effective therapeutic intervention. (1) In this study, we compared mutational profile of parathyroid carcinoma, adenoma, and normal parathyroid tissue using RNA-Seq based transcriptomics analysis and whole exome sequencing. A total of 40 parathyroid specimens [parathyroid carcinoma (n=8), adenoma (n=24), and normal tissue incidentally obtained from thyroidectomy for various reasons (n=8)] from 39 individuals (women n=34, 87%; mean age 51 year) were analyzed. Compared to adenoma and normal parathyroid groups, parathyroid carcinoma group had younger age (carcinoma 35 ± 12 vs. other 56 ± 16 year, p=0.001) and higher serum parathyroid hormone (PTH; 231 [145–474] vs. 114 [88–196] vs. 34 [29–41] pg/mL, p=0.001) prior to surgery. CDC73 mutation was found in 7 of 8 carcinoma specimens, which harbored germline mutation in 6 of them. Among top feature gene mutations for classifying adenoma and carcinoma, carcinoma-specific genes showed high specificity, whereas adenoma-related key features were largely overlapped with normal tissues. Transcriptional profiling revealed 546 carcinoma-specific differentially expressed genes (DEGs), 135 adenoma-specific DEGs, and 323 common DEGs. Hierarchical clustering with 546 carcinoma-specific DEGs detected four clusters with distinctive clinicopathologic characteristics (cluster 1 [n=12]: 7 normal tissues and 5 adenomas; cluster 2 and 3 [n=22]: all adenomas except one normal tissue; cluster 4 [n=9]: all parathyroid carcinomas except one adenoma). Carcinoma-specific DEGs include upregulation of GRIN2A, LYPD1, and SOX2 and downregulation of ENTPPL, MYO3B, and PIK3C2G. Gene ontology enrichment revealed that these DEGs were mainly involved in the binding of cell adhesion molecule, actin, and Rho GTPase, and extracellular matrix structural constituent. Two adenoma clusters significantly differed in urinary calcium excretion level (403 [312–488] vs. 205 [150–327], p=0.037) without significant differences in median PTH (102 [86–138] vs. 125 [92–229] pg/mL) and calcium level (11.1 ± 1.0 vs. 11.0 ± 0.9 mg/dL; P>0.05 for all). In summary, parathyroid carcinoma had distinctive transcriptional profiles which might improve the early detection of parathyroid carcinoma. Parathyroid adenomas were clustered into two groups with regard to urinary calcium excretion level based on transcriptional profiles, which merits further investigation. Reference: (1) Pandya C et al., JCI Insight. 2017 Mar 23; 2(6): e92061. Sources of Research Support: This study was supported by Severance Hospital Research Fund for Clinical Excellence (SHRC C-2019-0032; C-2020-0035).

Genome-wide analysis of differentially expressed lncRNA in sporadic parathyroid tumors.

Diagnosis of parathyroid carcinoma (PC) on histological examination is challenging. LncRNA profile study was conducted to find diagnostic biomarkers for PC. LncRNA arrays containing 91,007 lncRNAs as well as 29,857 mRNAs were used to assess parathyroid specimen (5 carcinomas and 6 adenomas). Bioinformatics analyses were also conducted to compare the microarray results between parathyroid carcinomas and adenomas (PAs). Differentially expressed lncRNAs of 11 PCs and 31 PAs were validated by real-time quantitative PCR. On the microarray data between PC and PA samples (fold change ≥ 2, P < 0.05), 1809 differentially expressed lncRNAs and 1349 mRNAs also were identified. All carcinomas were clustered in the same group by clustering analysis using dysregulated lncRNAs or mRNAs. Four lncRNAs (LINC00959, lnc-FLT3-2:2, lnc-FEZF2-9:2, and lnc-RP11-1035H13.3.1-2:1) identified were significantly dysregulated in further RT-PCR validation. The global "lncRNA score" calculated from the lncRNAs above also differentiated parathyroid carcinomas from adenomas. LncRNA profiling shows distinct differentially expressed lncRNAs in parathyroid neoplasm. They may play a key role in parathyroid cancer and serve as potential biomarkers to distinguish parathyroid cancers from parathyroid adenomas.

Long-term follow-up and novel splice donor mutation in MEN1 in a Chinese family

Heterozygous germline mutation of the MEN1 tumor suppressor gene is responsible for multiple endocrine neoplasia type 1. Parathyroid and thoracic neuroendocrine tumor specimens and DNA from two Han Chinese MEN1 family patients were analyzed using whole exome and Sanger sequencing. The proband (II-3) was sequentially diagnosed with pituitary adenoma, pancreatic tumor, adrenal cortical tumor, abdominal lipoma, and parathyroid adenoma during the 6-year follow-up. The son of the proband (III-6) was also diagnosed with a thoracic neuroendocrine tumor and a parathyroid adenoma during this period. Splice alterations were studied by RT-PCR and sequencing. The mutation impact was evaluated using bioinformatics. Sequence analysis revealed a novel splice donor mutation, MEN1 IVS9 + 1G > C, that changed the splicing mode of MEN1 to halt translation before two nuclear localization signals in the menin protein. Novel somatic mutations, MEN1 c.1402_1405delGAGG and c.286 C > T, were identified in the parathyroid adenoma of II-3 and thoracic neuroendocrine tumor of III-6, respectively, indicating a two-hit etiology of MEN1 syndrome. Our study revealed the clinical and genetic basis of MEN1 in this Han Chinese family and provides insight into MEN1 mechanisms, diagnosis, and management.

Surgical management of primary hyperparathyroidism.

We reviewed the surgical management of primary hyperparathyroidism through a retrospective chart review of 200 parathyroidectomy procedures performed over a 12year period. Epidemiological data and accuracy of radiological investigations used in identifying pathological parathyroid tissue location were assessed. We determined how often simultaneous removal of thyroid tissue was required during parathyroidectomy and the associated pathology. Radiology reports were screened to determine if confirmed thyroid pathology from histological specimens were referenced pre-operatively. Open parathyroid surgery was performed in 71%, the remainder endoscopically. 95% of parathyroid specimens were confirmed as benign adenomas, with eight cases of hyperplasia and two parathyroid carcinomas. Pre-operative ultrasound and SPECT-CT imaging demonstrated sensitivity of 55% and 73% respectively with regards correct adenoma localisation. Forty-nine patients (25%) underwent simultaneous partial thyroidectomy, 45 (92%) with dual pathology confirmed. Malignant thyroid lesions were identified in 18% (n = 8), Graves' disease 2% (n = 1), thyroiditis 9% (n = 4), multinodular goitre 56% (n = 25), unilateral nodule 4% (n = 2), hyperplasia 7% (n = 3) and intra-thyroid adenoma 4% (n = 2). Reference to these thyroid lesions was made in only 36% of preoperative imaging reports. In conclusion, synchronous thyroid surgery was carried out in a quarter of all parathyroidectomy procedures performed for treatment of primary hyperparathyroidism. Coincidental thyroid pathology was common. The limitations of pre-operative imaging in reliably locating involved parathyroid tissue are demonstrated and the importance of considering the potential need to perform thyroid surgery during parathyroidectomy and obtaining appropriate informed consent.

Oxidative stress and angiogenesis in primary hyperparathyroidism.

SummaryBackgroundThe inappropriate elevation of parathormone (PTH), which regulates the process of angiogenesis in parathyroid tissue, causes the changes of activity of enzymes responsible for the removal of free radicals. Parathyroidectomy (PTX) in patients with primary hyperparathyroidism (PHPT) lowers the level of PTH and leads to the reduction of risk of cardiovascular and all-cause mortality by normalization of the antioxidant status. Therefore, the aims of the study were to assess the activity of antioxidant enzymes and free radical reaction products in patients after parathyroidectomy, and to evaluate the correlation between the systemic oxidative stress and angiogenic parameters.Materials and methodsPatients with PHPT treated surgically were enrolled into the study. Total antioxidant capacity (TAC), total oxidative status (TOS), oxidative stress index (OSI), superoxide dismutase (SOD), ceruloplasmin (CER), lipid hydroperoxides (LHP) and malondialdehyde (MDA) were measured before and after parathyroidectomy. The immunohistological expression of angiogenic factors in parathyroid specimens was assessed by the BrightVision method from ImmunoLogic using murine monoclonal anti-human: anti-VEGF, anti-CD31 and anti-CD106 antibodies.ResultsThe significant increase of TAC, CER, reduction of TOS, MDA, SOD, especially for cytoplasmic form, and significant decrease of OSI, LHP were observed after PTX. There was no significant correlation between changes of oxidative stress markers and angiogenic parameters: VEGF, CD-31, CD-106 in parathyroid tissue. The correlation level was low and medium.ConclusionsParathyroidectomy causes down-regulation of lipid peroxidation processes and leads to reduction of oxidative stress in patients with PHPT. The decrease in the OSI is the results of down-regulation of oxidative stress in the postoperative period. The change of the antioxidant status has no impact on angiogenesis processes in parathyroid tissue.

The expression of p27Kip1 and β-catenin in multiple endocrine neoplasia type 1-related parathyroid tumors

Objective: To explore tissue expression of cyclin-dependent kinase inhibitor p27Kip1 and β-catenin in multiple endocrine neoplasia type1 (MEN1)-related parathyroid tumors (MHPT). Methods: Immunohistochemistry was performed to analyze the expression of p27Kip1 and β-catenin in parathyroid glands from 31 subjects with MHPT collected at Peking Union Medical College Hospital from 2002 to 2013. Five normal parathyroid glands were used as control. Results: In MHPT subjects, nuclear expression of p27Kip1 was absent in 4 (12.9%), weak in 10 (32.3%) and moderated staining in 17 parathyroid specimens (54.8%), respectively. While, in normal subjects, the nuclear expression of p27Kip1 was observed in all subjects and was stronger than that from MHPT subjects (P=0.001). As to the expression of β-catenin, normal parathyroid showed a distinct to moderate membrane staining, a moderate to weak cytoplasmic staining and negative nuclear staining. Similarly, MHPT exhibited a marked to moderate membrane (P=0.087), a moderated to weak cytoplasmic (P=0.357), and negative nuclear β-catenin staining. Conclusions: The expression of p27Kip1 is reduced or absent in MHPT tissue, and no nuclear expression of β-catenin is observed in the tumors, which suggesting p27Kip1, but not β-catenin nuclear accumulation, play a role in the development of the tumors.

Expression of TRAIL and Fas in Primary Hyperparathyroidism

ABSTRACTAim: Differentiating between parathyroid lesions is still difficult and ambiguous. In cases of primary hyperparathyroidism, appropriate and prompt diagnosis is of great importance for effective treatment and follow-up. A great amount of mechanisms contribute to the pathogenesis of primary hyperparathyroidism, such as disturbance in balance between pro- and anti-apoptotic factors. Therefore, we examined whether immunohistochemical expression of apoptotic factors, TNF-related apoptosis-inducing ligand (TRAIL) and Fas, could have clinical utility as a marker of proliferative lesions of parathyroid gland. Materials and methods: Parathyroid specimens of 58 consecutive patients who had undertaken surgery due to primary hyperparathyroidism were incubated with purified mouse monoclonal antihuman antibodies: anti-TRAIL and anti-Fas. Staining was considered positive when at least 5% of the cells showed immunoreactivity. Results: The percentage of cells which were positively stained for TRAIL in parathyroid hyperplasia was 9.65%, in parathyroid adenoma 8.31%, and in normal controls 2.24%. Immunoreactivity for TRAIL was detected in 91.89% of parathyroid hyperplasias, 85.71% of parathyroid adenomas, and none in healthy glands. The percentage of cells with a positive reaction to Fas in parathyroid hyperplasia was 8.92%, in parathyroid adenoma 8.09%, and in normal tissue 1.9%. The expression of Fas was found in 94.59% of parathyroid hyperplasias, 90.48% of parathyroid adenomas, and none in healthy glands. Conclusions: In our study, hyperplasias demonstrated the highest expression of TRAIL and Fas, whereas in adenomas it was increased compared to normal tissue, but lower than in hyperplasias. These factors could be an additive tool in the differential diagnosis of parathyroid lesions.

Proliferative Lesions of Parathyroid Glands: An Update for Practicing Pathologists.

Pathological lesions of parathyroid glands encompass a wide range of lesions ranging from developmental anomalies to inflammatory disorders to neoplastic processes. Proliferative lesions of parathyroid glands represent the commonest causes of hyperparathyroidism in clinical practice. However, the parathyroid specimens represent only a tiny fraction of the workload received in a non-specialist histopathology laboratory. As a result, the familiarity of the pathologists with the spectrum of parathyroid lesions is generally limited. An accurate diagnosis of the parathyroid lesions is challenging and a daunting task for both the clinicians and the pathologists. The traditional morphological approaches have limitations. Ancillary techniques of immunohistochemistry and molecular biology are being increasingly employed to resolve the diagnostic dilemmas. This review briefly describes the proliferative pathological lesions affecting the parathyroid glands and provides some useful tips on accurately diagnosing these lesions.

Analytical and clinical validation of parathyroid hormone (PTH) measurement in fine-needle aspiration biopsy (FNAB) washings

BackgroundParathyroid hormone (PTH) quantitation in fine needle aspirate biopsy (FNAB) saline washings complements current modalities for parathyroid tissue localization. ObjectivesTo establish the performance characteristics of the Roche Elecsys intact PTH immunoassay in FNAB needle washings and its diagnostic performance for the identification of parathyroid tissue. Design and methodsAccuracy, precision, reportable range, and analytical specificity and sensitivity for the intact PTH immunoassay in FNAB needle washings were established. For clinical validation, 93 specimens from 79 patients were evaluated. Diagnostic cut-offs were established via receiver operator characteristic (ROC) curve analysis. Performance of PTH in FNAB needle washings was compared to cytology. ResultsMeasurement of the PTH in FNAB needle washings demonstrated a matrix interference that was overcome by supplementation of the samples with a protein based matrix prior to analysis. ROC area under the curve (AUC) was 0.96 for PTH in FNAB needle washings. A PTH concentration ≥100pg/mL showed 100% specificity and 82% sensitivity for identifying parathyroid tissue. On histology-confirmed parathyroid specimens, 21/38 (55%) were correctly identified by cytology; whereas 31/38 (82%) were identified by PTH. ConclusionsMeasurement of PTH in FNAB washings complements cytology for identification of parathyroid tissue. Analytical validation to exclude interference in the PTH immunoassay and proper localization of the parathyroid tissue by ultrasound is necessary to ensure the robustness of the method.

Radioactive probe-guided parathyroidectomy for secondary hyperparathyroidism

Background The value of gamma probes in the surgical treatment of secondary hyperparathyroidism (sHPT) was determined. The aim of this study was to enhance the rate of successful total parathyroidectomy in patients with sHPT using intraoperative gamma probe investigations. Methods We retrospectively analyzed the clinical data of 48 sHPT patients between May 2007 and September 2011. Preoperative 99Tcm- methoxyisobutyl isonitrile (MIBI) scintigraphy and high-frequency ultrasonography were used for parathyroid localization. Thirty-five patients (group I) underwent conventional neck exploration and open parathyroidectomy. Thirteen patients (group II) underwent gamma probe-guided total parathyroidectomy and parathyroid transplantation. The two groups were compared in terms of the number of parathyroid resections, operative time, and postoperative changes in the blood levels of parathyroid hormone (PTH), calcium, and phosphate. Results The clinical manifestations, PTH and calcium levels, age distribution, and clinical characteristics did not differ between the two groups. The accuracy of preoperative 99Tcm-MIBI scintigraphy (89.74%) for the diagnosis of hyperparathyroidism did not differ from that of ultrasonography (81.25%). However, the accuracy of 99Tcm-MIBI scintigraphy (66.67%) for localizing hyperfunctioning parathyroids was significantly lower than that of ultrasonography (76.86%). The operation time was significantly longer in group I ((120±25) minutes) than in group II ((90±30) minutes). The accuracy of parathyroid identification was significantly higher in group II (92.59%) than in group I (80.39%). On average, significantly fewer parathyroid specimens were obtained in group I (2.5±0.5) than in group II (3.5±0.5). Compared with group I, group II showed a significant increase (15.4%) in the number of parathyroid resections. The PTH, calcium, and phosphate levels significantly decreased postoperatively in all patients. Conclusions Intraoperative gamma probe examination confirmed that the excised specimen was parathyroid tissue and improved the accuracy of parathyroid resection. The parathyroidectomy rate was increased by 15.4% due to the use of these probes. However, the probes did not detect all ectopic parathyroids, and further research is required to clarify the underlying reasons.

Radioactive probe-guided parathyroidectomy for secondary hyperparathyroidism.

The value of gamma probes in the surgical treatment of secondary hyperparathyroidism (sHPT) was determined. We retrospectively analyzed the clinical data of 48 sHPT patients between May 2007 and September 2011. Preoperative (99)Tc(m)- methoxyisobutyl isonitrile (MIBI) scintigraphy and high-frequency ultrasonography were used for parathyroid localization. Thirty-five patients (group I) underwent conventional neck exploration and open parathyroidectomy. Thirteen patients (group II) underwent gamma probe-guided total parathyroidectomy and parathyroid transplantation. The two groups were compared in terms of the number of parathyroid resections, operative time, and postoperative changes in the blood levels of parathyroid hormone (PTH), calcium, and phosphate. The clinical manifestations, PTH and calcium levels, age distribution, and clinical characteristics did not differ between the two groups. The accuracy of preoperative (99)Tc(m)-MIBI scintigraphy (89.74%) for the diagnosis of hyperparathyroidism did not differ from that of ultrasonography (81.25%). However, the accuracy of (99)Tc(m)-MIBI scintigraphy (66.67%) for localizing hyperfunctioning parathyroids was significantly lower than that of ultrasonography (76.86%). The operation time was significantly longer in group I (120+/-25) min than in group II (90+/-30) min. The accuracy of parathyroid specimens were obtained in group I (2.5+/-0.5) than in group II (3.5+/-0.5). Compared with group I, group II showed a significant increase (15.4%) in the number of parathyroid resections. The PTH, calcium, and phosphate levels significantly decreased postoperatively in all patients. Intraoperative gamma probe examination confirmed that the excised specimen was parathyroid tissue and improved the accuracy of parathyroid resection. The parathyroidectomy rate was increased by 15.4% due to the use of these probes. However, the probes did not detect all ectopic parathyroids, and further research is required to clarify the underlying reasons.

A Unique Use of Intraoperative Digital Specimen Radiography in the Treatment of Primary Hyperparathyroidism

Intraoperative evaluation of primary parathyroid specimens historically has been difficult. Frozen section diagnosis is not reliable and time-consuming. A visible rim of compressed normal parathyroid tissue is seen histologically surrounding a parathyroid adenoma and absent in parathyroid hyperplasia. Adjuncts such as radionuclide scanning and intraoperative parathyroid hormone levels help but are indirect methods of evaluation. Intraoperative digital specimen radiography (IDSR) of specimens is a novel technique that was compared with frozen section analysis. The study spanned a 12-month period. Thirty-six patients with primary hyperparathyroidism met eligibility criteria. Resected parathyroid specimens were evaluated with the Bioptics PiXarray100 digital radiograph system and pathologic evaluation. Thirty-nine specimens were evaluated with IDSR, reflecting three patients with multiple glands excised. Thirty patients were pathologically found to have adenomas (83%) and six were hyperplasia (17%). Twenty-seven of 30 adenoma specimens had an IDSR visible rim of compressed tissue (sensitivity 90%) and no hyperplasia specimens had an IDSR visible rim (specificity 100%). Fisher's exact test was significant (P = 0.000). Frozen section correctly diagnosed adenoma in only 16 of 30 specimens (sensitivity 53%). IDSR of parathyroid specimens is a powerful modality in the real-time differentiation of parathyroid adenomas from hyperplasia (sensitivity 90%). This technique is noninferior to the current "gold standard," frozen section (sensitivity 53%). We propose IDSR evaluation of all parathyroid surgical specimens for the immediate diagnosis of adenoma versus hyperplasia.

Head and Neck Pathology

Most malignant tumors in the head and neck are conventional keratinizing squamous cell carcinomas, and their microscopic diagnosis usually pose little challenge for pathologists. However, other conditions including rare malignancies can be encountered so infrequently that diagnosis or grading may be challenging. This issue of Pathology Case Reviews attempts to answer some of the more common questions that pathologists ask of their colleagues with an expertise in oral and/or head and neck pathology. These include the diagnosis and grading of oral epithelial dysplasia, the differential diagnosis of basaloid squamous carcinoma, and the relevance of HPV infection in squamous cancer of the oropharynx. Complementary articles discuss the diagnosis and grading of mucoepidermoid carcinoma, the clinical and pathologic features of salivary duct carcinoma, the diagnostic criteria of parathyroid carcinoma, and the microscopic and immunophenotypic features of marginal zone (MALT) lymphoma of the parotid gland. The diagnosis and terminology of precursor lesions to carcinomas of the upper aerodigestive tract is a challenging area for many pathologists because of the subtle microscopic features that form the basis of grading. This area is important because grading often guides clinical management for patients with premalignant disease. In their article, Drs Speight and Torres-Rendon present a case of squamous dysplasia of the oral tongue that progressed to squamous cell carcinoma. They clarify the clinical presentation of oral epithelial dysplasia and provide terminology and the histologic criteria for grading. The practical differential diagnosis and clinical management of oral epithelial dysplasia is also covered. Mucoepidermoid carcinoma is the most common primary malignancy of the salivary glands. Microscopic grading seems to play an important role in treatment selection and patient prognosis, and yet no common grading system has been agreed on. Drs Griffith and Seethala present a case of mucoepidermoid carcinoma arising in a minor salivary gland of the buccal mucosa. They present the differential diagnosis for mucoepidermoid carcinoma and then compare competing microscopic grading systems, problems in their application, and the clinical significance of grading. Salivary duct carcinoma is a rare, high-grade adenocarcinoma of the major salivary glands with a poor prognosis. Despite the distinctive cytologic and histologic features of this tumor and its resemblance to apocrine-type ductal carcinoma of the breast, salivary duct carcinoma can be mistaken for several other high-grade malignancies including mucoepidermoid carcinoma. We present a case of salivary duct carcinoma of the parotid gland and discuss the diagnostic features in fine needle aspirate and histologic samples, including the important role immunohistochemical assessment plays in establishing the diagnosis. Given the prevalence of primary hyperparathyroidism and the routine nature of parathyroid specimens in surgical pathology, a clear understanding of the diagnostic criteria for parathyroid carcinoma is required. Drs Khanafshar and van Zante discuss a case of parathyroid carcinoma, present the diagnostic criteria for a diagnosis of carcinoma and the diagnostic category of atypical adenoma. The applicability of a limited panel of immunostains is additionally reviewed. Another challenging area of head and neck pathology is the diagnosis of marginal zone (MALT) lymphoma, especially given the overlapping findings between long-standing autoimmune sialadenitis and MALT lymphoma. Drs McAlhany, Etzell, and Treseler present a case of MALT lymphoma of the parotid and discuss the histologic features, immunophenotype, and differential diagnosis. Recent advances in the understanding of the etiology of squamous cell cancer of the head and neck has shown that this group of tumors is made up of distinct subtypes with unique biological and histologic features. It has now been established that most squamous cell carcinomas arising in the oropharynx (base of tongue and lingual tonsils) are etiologically associated with oncogenic strains of human papillomavirus (HPV) rather than tobacco and alcohol, the traditional risk factors for head and neck cancer. Many HPV-associated squamous cell carcinomas are nonkeratinizing with a basaloid appearance. In their article, Drs Mills, Stelow, and Mills discuss the diagnosis of basaloid squamous cell carcinoma and highlight the broad differential that must be considered when a basaloid or small cell malignancy is encountered in the head and neck region. Finally, given that treatment paradigms may soon rely on pathologists to differentiate HPV-driven tumors and HPV-negative tumors, pathologists should make an effort now to understand the typical clinical presentation and histology of HPV-associated squamous cell carcinoma. A basic understanding of the indications for and limitations of immunohistochemistry for p16 and in situ hybridization for the identification of high-risk HPV is also required. The final article in this journal is an orientation to HPV-associated squamous cell carcinoma of the oropharynx and provides practical advice on how to evaluate and report squamous cancers of the oropharynx and the clinical implications of the diagnosis.FIGUREFIGURE

Evaluation of formalin-fixed paraffin-embedded tissues in the proteomic analysis of parathyroid glands

BackgroundProteomic research in the field of parathyroid tissues is limited by the very small dimension of the glands and by the low incidence of cancer lesions (1%). Formalin-fixed paraffin-embedded (FFPE) tissue specimens are a potentially valuable resource for discovering protein cancer biomarkers. In this study we have verified the applicability of a heat induced protein extraction from FFPE parathyroid adenoma tissues followed by a gel-based or gel-free proteomic approach in order to achieve protein separation and identification.ResultsThe best results for high quality MS spectra and parameters, were obtained by using a gel-free approach, and up to 163 unique proteins were identified. Similar results were obtained by applying both SDS-out and SDS-out + TCA/Acetone techniques during the gel-free method. Western blot analysis carried out with specific antibodies suggested that the antigenicity was not always preserved, while specific immunoreactions were detected for calmodulin, B box and SPRY domain-containing protein (BSPRY), peroxiredoxin 6 (PRDX 6) and parvalbumin.ConclusionsIn spite of some limitations mainly due to the extensive formalin-induced covalent cross-linking, our results essentially suggest the applicability of a proteomic approach to FFPE parathyroid specimens. From our point of view, FFPE extracts might be an alternative source, especially in the validation phase of protein biomarkers when a large cohort of samples is required and the low availability of frozen tissues might be constraining.

Viability of cryopreserved parathyroid tissue: when is continued storage versus disposal indicated?

Parathyroid cryopreservation is used for potential autografting in patients who are rendered hypocalcemic following surgery. Cryopreservation employs multiple resources and carries a significant cost for processing and storage of tissue. Importantly, the length of time that parathyroid tissue remains functional after cryopreservation is not known. The goal of our study was to assess ex-vivo viability of parathyroid tissue in relation to the length of time in storage. We sought to define the appropriate time frame for tissue utilization and disposal to assist with long-term surgical planning. From 1991 to 2006, 501 parathyroid specimens from 149 patients were cryopreserved at -80 degrees C according to standardized techniques. A single trained technician assessed viability, using a hemacytometer to count viable (clear cell) and nonviable (blue cell) tissue. Univariate analysis was performed to correlate length of preservation, diagnosis with viability. We evaluated 106 random parathyroid specimens. Samples were divided into two groups: those stored>24 months and those stored<or=24 months. Eleven (10%) of 106 specimens were deemed viable. Length of storage time was associated with ex-vivo tissue viability. Viability of samples cryopreserved<or=24 months was 71% (10/14) versus 1% (1/92) of those specimens stored>24 months (p<0.001). Viability of cryopreserved parathyroid cells is associated with duration of storage. Parathyroids preserved for greater than 24 months are unlikely to be viable. It seems reasonable to limit parathyroid cryopreservation to 24 months when frozen at -80 degrees C. Further studies are needed to optimize the process of cryopreservation to enhance cell viability.