Clinical significance of CYP11B2 immunostaining in unilateral primary aldosteronism

Objective

The associations between adrenal histopathology, lateralization studies, and surgical outcomes in primary aldosteronism remain poorly characterized. We examined the value of immunohistochemical analysis of CYP11B2 for evaluation of adrenalectomy outcomes after anatomical versus functional subtyping.

Design

A retrospective multicenter study of 277 patients operated for primary aldosteronism who had an adrenalectomy sample available in the Finnish biobanks from 1 January 2000 to 31 December 2019. Adrenal slides from biobanks were analyzed centrally after CYP11B2 and CYP11B1 staining. Clinical data were obtained from patient registries. Histopathological diagnosis and cure after surgery were assessed as outcome measures.

Results

Re-evaluation with CYP11B2 staining changed the histopathological diagnosis in 91 patients (33%). The presence of a CYP11B2-positive adenoma and the use of functional subtyping independently predicted clinical cure of primary aldosteronism. CYP11B2-positive <7 mm nodules were more frequent in patients without clinical cure, whereas CYP11B2-positive micronodules were common in all patients and had no impact on adrenalectomy outcomes. Small CYP11B2-positive nodules and micronodules were equally prevalent regardless of the subtyping method applied. Clinical cure rates were lower and CYP11B2-negative adenomas more common after adrenalectomy based on anatomical imaging than functional studies.

Conclusions

Incorporating CYP11B2 staining in histopathological diagnosis enhances the prediction of surgical outcomes in primary aldosteronism. A finding of CYP11B2-positive adenoma is indicative of cure of primary aldosteronism, whereas smaller CYP11B2-positive nodules associate with poorer results at postoperative evaluation. Functional subtyping methods decrease the operations of CYP11B2-negative adenomas and are superior to anatomical imaging in identifying unilateral primary aldosteronism.

Immunohistochemical Glucagon-like Peptide-1 Receptor Expression in Human Insulinomas

Insulinomas are rare functional pancreatic neuroendocrine tumours, which metastasize in 10% of cases. As predicting the prognosis can be challenging, there is a need for the determination of clinicopathological factors associated with metastatic potential. The aim of this study is to evaluate the glucagon-like peptide-1 receptor (GLP-1R) expression in insulinomas and to analyse its association with clinicopathological features and patient outcome. This retrospective study involves pancreatic tumour tissue samples from fifty-two insulinoma patients. After histological re-evaluation, formalin-fixed paraffin-embedded tissue samples were processed into tissue microarrays and stained immunohistochemically with a monoclonal GLP-1R antibody. Forty-eight of the forty-nine (98%) non-metastatic tumours expressed GLP-1R, while one non-metastatic, multiple endocrine neoplasia type 1 (MEN1)-related tumour and all three of the metastatic tumours lacked GLP-1R expression. The lack of GLP-1R expression was associated with impaired overall survival, larger tumour diameter, higher Ki-67 PI and weaker insulin staining. Somatostatin receptor 1-5 expression did not differ between GLP-1R-positive and GLP-1R-negative insulinomas. In conclusion, the lack of GLP-1R expression is associated with metastatic disease and impaired survival in insulinoma patients. Thus, GLP-1R expression could be a useful biomarker in estimating the metastatic potential of the tumour and the prognosis of surgically treated patients.

Somatostatin receptor expression in Merkel cell carcinoma: correlation with clinical data

BACKGROUND

Merkel cell carcinoma (MCC) is a rare, high-grade neuroendocrine neoplasm (NEN) of the skin. Somatostatin receptors (SSTRs) are G protein-linked receptors that regulate cell proliferation and growth. SSTRs are expressed in many NENs; however, scant information is available on their expression in MCCs or their association with clinical parameters and patient outcomes.

MATERIAL AND METHODS

This retrospective study was conducted at Helsinki University Hospital and the University of Helsinki. Using a tissue microarray, we investigated SSTR1-5 expression by immunohistochemistry in 99 MCC tissue samples. Samples were collected between 1983 and 2017 and coupled with the patients' clinical data.

RESULTS

SSTR2-SSTR5 were detected in 69%, 6%, 4%, and 1% of the tumours, respectively. However, SSTR1 expression was not observed. Cytoplasmic SSTR2 positivity was associated with metastatic disease at the time of diagnosis (p = 0.009), but it did not correlate with disease-specificity or overall survival.

CONCLUSION

SSTR2-5 expression was observed in MCCs. In particular, SSTR2 expression is clinically valid because it is associated with metastatic disease at the time of diagnosis and can thus serve as a prognostic marker. Moreover, SSTR2 overexpression provides a molecular basis for tumour imaging and treatment with somatostatin analogues.

Immunohistochemical somatostatin receptor expression in insulinomas

Insulinomas are rare pancreatic neuroendocrine tumours. Most patients can be cured with surgery, but patients with a metastatic disease show impaired survival. The aim of this study was to evaluate somatostatin receptor (SSTR) 1-5 expression in insulinomas and to correlate the expression profile with clinicopathological variables and with patient outcome. This retrospective study involved 52 insulinoma patients. After histological re-evaluation, formalin-fixed paraffin-embedded tissue samples were processed into tissue microarrays and stained immunohistochemically with monoclonal SSTR1-5 antibodies. All the 52 tumours (49 non-metastatic, 3 metastatic) expressed at least one SSTR subtype. SSTR2 was expressed most frequently (71%), followed by SSTR3 (33%), SSTR1 (27%), SSTR5 (6%) and SSTR4 (0%). SSTR3 expression was associated with a larger tumour size (median diameter 19 mm vs. 13 mm, p = 0.043), and SSTR3 and SSTR5 expression were associated with impaired overall survival [HR 3.532 (95% CI 1.106-11,277), p = 0.033, and HR 6.805 (95% CI 1.364-33.955), p = 0.019 respectively]. Most insulinomas express SSTR2, which may be utilized in diagnostic imaging, and in planning individualized treatment strategies for insulinoma patients. Further studies are needed to clarify the association between SSTR profile and overall survival.

Adrenal androgens versus cortisol for primary aldosteronism subtype determination in adrenal venous sampling

OBJECTIVE

We examined if measurement of adrenal androgens adds to subtype diagnostics of primary aldosteronism (PA) under cosyntropin-stimulated adrenal venous sampling (AVS).

DESIGN

A prospective pre-specified secondary endpoint analysis of 49 patients with confirmed PA, of whom 29 underwent unilateral adrenalectomy with long-term follow-up.

METHODS

Concentrations of androstenedione, dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulphate (DHEAS) were measured during AVS in addition to aldosterone and cortisol. Subjects with lateralisation index (LI) of ≥4 were treated with unilateral adrenalectomy, and the immunohistochemical subtype was determined with CYP11B2 and CYP11B1 stains. The performance of adrenal androgens was evaluated by receiver operating characteristics (ROC) curve analyses in adrenalectomy and medical therapy groups.

RESULTS

During AVS, the correlations between cortisol and androstenedione, DHEA and DHEAS for LI and selectivity index (SI) were highly significant. The right and left side SIs for androstenedione and DHEA were higher (p < .001) than for cortisol. In ROC analysis, the optimal LI cut-off values for androstenedione, DHEA and DHEAS were 4.2, 4.5 and 4.6, respectively. The performance of these LIs for adrenal androgens did not differ from that of cortisol.

CONCLUSIONS

Under cosyntropin-stimulated AVS, the measurement of androstenedione and DHEA did not improve the cannulation selectivity. The performance of cortisol and adrenal androgens are confirmatory but not superior to cortisol-based results in lateralisation diagnostics of PA.

Lateralization in 11 C-Metomidate PET and outcome of adrenalectomy in primary aldosteronism

INTRODUCTION

Subtype classification method is essential when considering adrenalectomy as a possible treatment for primary aldosteronism. We aimed to retrospectively evaluate surgical outcomes of primary aldosteronism in patients who had undergone ¹¹ C-metomidate positron emission tomography (¹¹ C-MTO-PET) for subtype classification.

METHODS

Postoperative clinical and biochemical cure and histopathological diagnosis from biobank samples were retrospectively evaluated in 44 patients who had all undergone preoperative ¹¹ C-MTO-PET with or without adrenal venous sampling (AVS). We compared those operated based on ¹¹ C-MTO-PET alone and those with concordant or discordant lateralization in ¹¹ C-MTO-PET and AVS studies according to postoperative immunohistochemical findings and biochemical and clinical cure.

RESULTS

Adrenalectomy side was based on ¹¹ C-MTO-PET alone in 14 cases and on AVS in 30 cases of whom 42 achieved complete and two partial biochemical cures. Among those who underwent AVS and were operated according to it, the two lateralization methods were concordant in 22 cases and discordant in 8 cases. Similar immunohistochemical profiles and cure rates were seen after ¹¹ C-MTO-PET alone or AVS-based operations. Respectively, those with concordant or discordant ¹¹ C-MTO-PET and AVS lateralization did not differ in surgical outcome. Together, we found errors of lateralization diagnostics with ¹¹ C-MTO-PET in 18% and with AVS in 3% among those eligible for adrenal surgery.

CONCLUSIONS

Outcomes of adrenalectomy based on clinically significant lateralization in ¹¹ C-MTO-PET alone correspond to those based on ¹¹ C-MTO-PET with concordant AVS lateralization. However, our results suggest that diagnosis of unilateral PA should be performed with caution with ¹¹ C-MTO-PET in case of discordant lateralization studies.

Automated assessment of Ki-67 proliferation index in neuroendocrine tumors by deep learning

The Ki‐67 proliferation index (PI) is a prognostic factor in neuroendocrine tumors (NETs) and defines tumor grade. Analysis of Ki‐67 PI requires calculation of Ki‐67‐positive and Ki‐67‐negative tumor cells, which is highly subjective. To overcome this, we developed a deep learning‐based Ki‐67 PI algorithm (KAI) that objectively calculates Ki‐67 PI. Our study material consisted of NETs divided into training (n = 39), testing (n = 124), and validation (n = 60) series. All slides were digitized and processed in the Aiforia^® Create (Aiforia Technologies, Helsinki, Finland) platform. The ICC between the pathologists and the KAI was 0.89. In 46% of the tumors, the Ki‐67 PIs calculated by the pathologists and the KAI were the same. In 12% of the tumors, the Ki‐67 PI calculated by the KAI was 1% lower and in 42% of the tumors on average 3% higher. The DL‐based Ki‐67 PI algorithm yields results similar to human observers. While the algorithm cannot replace the pathologist, it can assist in the laborious Ki‐67 PI assessment of NETs. In the future, this approach could be useful in, for example, multi‐center clinical trials where objective estimation of Ki‐67 PI is crucial.

Characteristics and outcomes of the Finnish ectopic ACTH syndrome cohort

PURPOSE

Ectopic ACTH syndrome (EAS) is rare. We established a national cohort to increase awareness and address unmet needs.

METHODS

The Finnish national EAS cohort includes 60 patients diagnosed in 1997-2016. We assessed clinical features, diagnostic work-ups, treatments, incidence, and outcomes of subgroups occult tumor (OT), well-differentiated neuroendocrine tumor G1/G2 (NETG1/G2) and NET G3/neuroendocrine carcinoma (NETG3/NEC).

RESULTS

The distribution of OT, NETG1/G2, and NETG3/NEC was 10 (17%), 20 (33%), and 30 (50%), respectively; and median follow-up 22 months (0-249). Annual incidence (0.20-0.93 per million inhabitants) and tumor subgroups (OT vs. NEC) varied across the country. The longest diagnostic delay from EAS onset to radiological tumor identification was 48 months. In NET/NEC, 6/50 (12%) were diagnosed 1-24 years before EAS onset. Osteoporotic fractures (32%) and severe infections (55%) were common. The CRH stimulation test accurately diagnosed EAS in 25/31 (81%). Metyrapone (≤6 g daily, prescribed in 88%) was well tolerated. In NETG1/G2, 13/20 (65%) underwent curative resection of the primary tumor; four experienced recurrence within 2-12 years. In OT, 70% underwent bilateral adrenalectomy. Five-year overall survival in OT, NETG1/G2, and NETG3/NEC was 90%, 55%, and 0%, respectively (P < 0.001). Morning cortisol, hypokalemia, infections, metastatic disease, and acute onset were negative, whereas resection of the primary tumor and bilateral adrenalectomy were positive predictors of survival.

CONCLUSIONS

NET/NEC may precede EAS onset by several years. In NETG1/G2, recurrences may occur > 10 years after successful primary surgery. Tumor subgroup (OT, NETG1/G2, NEC) was an independent predictor of survival.

Filamin A and parafibromin expression in parathyroid carcinoma

OBJECTIVE

Parathyroid carcinoma (PC), atypical parathyroid tumours (APT) and parathyroid adenoma (PA), all present with hypercalcemia. Diminished calcium-sensing receptor (CaSR) expression is reported in PC but is rare in benign tumours. Filamin A (FLNA) binds to the CaSR and activates the mitogen-activated protein kinase (MAPK) signalling pathway. FLNA is related to tumour aggressiveness in several cancers, but its role in parathyroid neoplasia is unknown.

DESIGN

We examined FLNA, CaSR and parafibromin expression in PCs (n = 32), APTs (n = 44) and PAs (n = 77) and investigated their potential as diagnostic and/or prognostic markers.

METHODS

Tissue microarray slides were immunohistochemically stained with antibodies for FLNA, CaSR and parafibromin. Staining results were correlated with detailed clinical data.

RESULTS

All tumours stained positively for CaSR, with two tumours (one PC and one APT) showing diminished expression. Carcinomas were characterized by increased cytoplasmic FLNA expression compared to APTs and PAs (P = 0.004). FLNA expression was not correlated with Ki-67 proliferation index or loss of parafibromin expression. Cytoplasmic FLNA expression was also associated with higher serum calcium, PTH concentrations and male sex (P = 0.014, P = 0.017 and P = 0.049 respectively). Using a combined marker score, we found that parathyroid tumours with low FLNA expression and positive parafibromin staining were extremely likely to be benign (P < 0.001).

CONCLUSION

Cytoplasmic and membranous FLNA expression is increased in parathyroid carcinomas compared to benign tumours. A combined FLNA and parafibromin expression score shows potential as a prognostic predictor of indolent behaviour in parathyroid neoplasms.

Functional imaging with 11C-metomidate PET for subtype diagnosis in primary aldosteronism

OBJECTIVE

Endocrine Society guidelines recommend adrenal venous sampling (AVS) in primary aldosteronism (PA) if adrenalectomy is considered. We tested whether functional imaging of adrenal cortex with 11C-metomidate (11C-MTO) could offer a noninvasive alternative to AVS in the subtype classification of PA.

DESIGN

We prospectively recruited 58 patients with confirmed PA who were eligible for adrenal surgery.

METHODS

Subjects underwent AVS and 11C-MTO-PET without dexamethasone pretreatment in random order. The lateralization of 11C-MTO-PET and adrenal CT were compared with AVS in all subjects and in a prespecified adrenalectomy subgroup in which the diagnosis was confirmed with immunohistochemical staining for CYP11B2.

RESULTS

In the whole study population, the concordance of AVS and 11C-MTO-PET was 51% and did not differ from that of AVS and adrenal CT (53%). The concordance of AVS and 11C-MTO-PET was 55% in unilateral and 44% in bilateral PA. In receiver operating characteristics analysis, the maximum standardized uptake value ratio of 1.16 in 11C-MTO-PET had an AUC of 0.507 (P = n.s.) to predict allocation to adrenalectomy or medical therapy with sensitivity of 55% and specificity of 44%. In the prespecified adrenalectomy subgroup, AVS and 11C-MTO-PET were concordant in 10 of 19 subjects with CYP11B2-positive adenoma and in 6 of 10 with CYP11B2-positivity without an adenoma.

CONCLUSIONS

The concordance of 11C-MTO-PET with AVS was clinically suboptimal, and did not outperform adrenal CT. In a subgroup with CYP11B2-positive adenoma, 11C-MTO-PET identified 53% of cases. 11C-MTO-PET appeared to be inferior to AVS for subtype classification of PA.

PCSK2 expression in neuroendocrine tumors points to a midgut, pulmonary, or pheochromocytoma-paraganglioma origin

Neuroendocrine tumors (NETs) are often diagnosed from the metastases of an unknown primary tumor. Specific immunohistochemical (IHC) markers indicating the location of a primary tumor are needed. The proprotein convertase subtilisin/kexin type 2 (PCSK2) is found in normal neural and neuroendocrine cells, and known to express in NETs. We investigated the tissue microarray (TMA) of 86 primary tumors from 13 different organs and 9 metastatic NETs, including primary tumor‐metastasis pairs, for PCSK2 expression with polymer‐based IHC. PCSK2 was strongly positive in all small intestine and appendiceal NETs, the so‐called midgut NETs, in most pheochromocytomas and paragangliomas, and in some of the typical and atypical pulmonary carcinoid tumors. NETs showing strong positivity were re‐evaluated in larger tumor cohorts confirming the primary observation. In the metastases, the expression of PCSK2 mirrored that of the corresponding primary tumors. We found negative or weak staining in NETs from the thymus, gastric mucosa, pancreas, rectum, thyroid, and parathyroid. PCSK2 expression did not correlate with Ki‐67 in well‐differentiated NETs. Our data suggest that PCSK2 positivity can indicate the location of the primary tumor. Thus, PCSK2 could function in the IHC panel determined from screening metastatic NET biopsies of unknown primary origins.

Somatostatin receptor expression in parathyroid neoplasms

INTRODUCTION

Parathyroid carcinoma represents a rare cause of primary hyperparathyroidism. Distinguishing carcinoma from the benign tumors underlying primary hyperparathyroidism remains challenging. The diagnostic criteria for parathyroid carcinoma are local and/or metastatic spreading. Atypical parathyroid adenomas share other histological features with carcinomas but lack invasive growth. Somatostatin receptors are commonly expressed in different neuroendocrine tumors, but whether this also holds for parathyroid tumors remains unknown.

AIM

Our aim is to examine the immunohistochemical expression of somatostatin receptor 1-5 in parathyroid typical adenomas, atypical adenomas and carcinomas.

METHODS

We used a tissue microarray construct from a nationwide cohort of parathyroid carcinomas (n = 32), age- and gender-matched typical parathyroid adenomas (n = 72) and atypical parathyroid adenomas (n = 27) for immunohistochemistry of somatostatin receptor subtypes 1-5. We separately assessed cytoplasmic, membrane and nuclear expression and also investigated the associations with histological, biochemical and clinical characteristics.

RESULTS

All parathyroid tumor subgroups expressed somatostatin receptors, although membrane expression appeared negligible. Except for somatostatin receptor 1, expression patterns differed between the three tumor types. Adenomas exhibited the weakest and carcinomas the strongest expression of somatostatin receptor 2, 3, 4 and 5. We observed the largest difference for cytoplasmic somatostatin receptor 5 expression.

CONCLUSIONS

Parathyroid adenomas, atypical adenomas and carcinomas all express somatostatin receptor subtypes 1-5. Somatostatin receptor 5 may serve as a potential tumor marker for malignancy. Studies exploring the role of somatostatin receptor imaging and receptor-specific therapies in patients with parathyroid carcinomas are needed.

Somatostatin Receptor Expression Is Associated With Metastasis and Patient Outcome in Pulmonary Carcinoid Tumors

CONTEXT

Pulmonary carcinoids (PCs) belong to neuroendocrine tumors that often overexpress somatostatin receptors (SSTRs). This overexpression provides a molecular basis for tumor imaging and treatment with somatostatin analogs.

OBJECTIVE

To evaluate SSTR1 to SSTR5 distribution in a large set of PC tumors and to investigate whether the expression is associated with clinicopathological and outcome data.

DESIGN, SETTING, AND PATIENTS

This retrospective study was conducted at Helsinki University Hospital and University of Helsinki. It included 178 PC tumors coupled with patients' clinical data retrieved through Finnish biobanks. After histological reclassification, tissue specimens were processed into next-generation tissue microarray format and stained immunohistochemically with monoclonal SSTR1 to SSTR5 antibodies.

MAIN OUTCOME MEASURE

SSTR1 to SSTR5 expression in PC tumors.

RESULTS

Expression of SSTR1 to SSTR5 was detected in 52%, 75%, 56%, 16%, and 32% of the tumors, respectively. Membrane-bound staining was observed for all receptors. SSTR2 negativity and SSTR4 positivity was associated with lymph node involvement at the time of surgery (P = 0.014 and P = 0.017, respectively) and with distant metastasis (P = 0.027 and P = 0.015, respectively). SSTR3 and SSTR4 expression was associated with increased risk of shorter survival [P = 0.046, hazard ratio (HR) 4.703, 95% CI 1.027 to 21.533; and P = 0.013, HR 6.64, 95% CI 1.48 to 29.64, respectively], whereas expression of SSTR1 and SSTR2 was associated with improved outcome (P = 0.021, HR 0.167, 95% CI 0.037 to 0.765; and P = 0.022, HR 0.08, 95% CI 0.01 to 0.70, respectively).

CONCLUSION

SSTR1 to SSTR5 expression is observed in PCs. As SSTR expression is associated with the tumor's metastatic potential and patient outcome, these receptors may offer the possibility for individualized prognosis estimation.

65 YEARS OF THE DOUBLE HELIX: Genetics informs precision practice in the diagnosis and management of pheochromocytoma

Although the authors of the present review have contributed to genetic discoveries in the field of pheochromocytoma research, we can legitimately ask whether these advances have led to improvements in the diagnosis and management of patients with pheochromocytoma. The answer to this question is an emphatic Yes! In the field of molecular genetics, the well-established axiom that familial (genetic) pheochromocytoma represents 10% of all cases has been overturned, with >35% of cases now attributable to germline disease-causing mutations. Furthermore, genetic pheochromocytoma can now be grouped into five different clinical presentation types in the context of the ten known susceptibility genes for pheochromocytoma-associated syndromes. We now have the tools to diagnose patients with genetic pheochromocytoma, identify germline mutation carriers and to offer gene-informed medical management including enhanced surveillance and prevention. Clinically, we now treat an entire family of tumors of the paraganglia, with the exact phenotype varying by specific gene. In terms of detection and classification, simultaneous advances in biochemical detection and imaging localization have taken place, and the histopathology of the paraganglioma tumor family has been revised by immunohistochemical-genetic classification by gene-specific antibody immunohistochemistry. Treatment options have also been substantially enriched by the application of minimally invasive and adrenal-sparing surgery. Finally and most importantly, it is now widely recognized that patients with genetic pheochromocytoma/paraganglioma syndromes should be treated in specialized centers dedicated to the diagnosis, treatment and surveillance of this rare neoplasm.

N-Glycomic Profiling of Pheochromocytomas and Paragangliomas Separates Metastatic and Nonmetastatic Disease

CONTEXT

No effective methods for separating primary pheochromocytomas and paragangliomas with metastatic potential are currently available. The identification of specific asparagine-linked glycan (N-glycan) structures, which are associated with metastasized pheochromocytomas and paragangliomas, may serve as a diagnostic tool.

OBJECTIVE

To identify differences in N-glycomic profiles of primary metastasized and nonmetastasized pheochromocytomas and paragangliomas.

SETTING

This study was conducted at Helsinki University Hospital, University of Helsinki, and Glykos Finland Ltd. and included 16 pheochromocytomas and paragangliomas: 8 primary metastasized pheochromocytomas or paragangliomas and 8 nonmetastasized tumors.

METHODS

N-glycan structures were analyzed with matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) profiling of formalin-fixed, paraffin-embedded tissue samples.

MAIN OUTCOME MEASURE

N-glycan profile of tumor tissue.

RESULTS

Four groups of neutral N-glycan signals were more abundant in metastasized tumors than in nonmetastasized tumors: complex-type N-glycan signals of cancer-associated terminal N-acetylglucosamine, multifucosylated glycans (complex fucosylation), hybrid-type N-glycans, and fucosylated pauci-mannose-type N-glycans. Three groups of acidic N-glycans were more abundant in metastasized tumors: multifucosylated glycans, acid ester-modified (sulfated or phosphorylated) glycans, and hybrid-type/monoantennary N-glycans. Fucosylation and complex fucosylation were significantly more abundant in metastasized paragangliomas and pheochromocytomas than in nonmetastasized tumors for individual tests but were over the false positivity critical rate, when adjusted for multiplicity testing.

CONCLUSIONS

MALDI-TOF MS profiling of primary pheochromocytomas and paragangliomas can identify diseases with metastatic potential based on their different N-glycan profiles. Thus, malignancy-linked N-glycan structures may serve as potential diagnostic tools for pheochromocytomas and paragangliomas.

Max Schottelius: Pioneer in Pheochromocytoma

First descriptions of diseases attract tremendous interest because they reveal scientific insight even in retrospect. Max Schottelius, the pathologist contributing the first histological description of pheochromocytoma, remains anonymous. We reviewed the description by Schottelius and weighed the report in modern context. Schottelius described the classical diagnostic elements of pheochromocytoma, including the brown appearance after exposure to chromate-containing Mueller’s fixative. This color change, known as chromaffin reaction, results from oxidation of catecholamines and is reflected in the name pheochromocytoma, meaning dusky-colored chromate-positive tumor. Thus Schottelius performed the first known histochemical contribution to diagnosis, which is today standard with immunohistochemistry for chromogranin.

A nationwide study on parathyroid carcinoma

BACKGROUND

Parathyroid carcinoma (PC) is rare and diagnostically challenging. Reported outcomes are rather poor and the incidence might be increasing.

MATERIAL AND METHODS

We performed a nationwide study on all cases (n= 32) diagnosed in 2000-2011 in Finland, and compared clinical and histopathological characteristics and outcome to atypical parathyroid (APA; n= 28) and parathyroid adenomas (PA; n= 72). The incidence in years 1955-1999 was compared to that in 2000-2013.

RESULTS

Preoperatively, calcium and parathyroid hormone concentrations were higher in PC compared to APA and PA (1.76, 1.56 and 1.44 mmol/l, p < .001; and 989, 355 and 160 μmol/l, p < .001, respectively). Calcium was ≤1.77 mmol/l for all PAs. Hospitalization (44% vs. 22% and 3%, respectively, p = .01), renal (50% vs. 48% vs. 22%, respectively, p = .01) and bone (47% vs. 15% vs. 38%, respectively p = .002) manifestations were more common. PC and APA tumors were larger than PA (p < .001). Histopathological characteristics of PC compared to PA are increased mitotic activity (p= .001), chief cells (p = .003), diffuse growth pattern (p < .001), higher Ki67 (p< .001) and negative parafibromin (p < .001). One PC (1/18) and one APA (1/16) patient had a CDC73 mutation. After 6.7 (2-13.9) years of follow-up, 9.4% of PC had residual, 21% recurrent disease and 12.5% died of disease. Overall mortality did not differ between subgroups (p = .094). Recurrent PC was characterized by vascular invasion, lymph node metastases, high mitotic activity, necrosis and negative parafibromin. Incidence increased from 1.42 (range 0.52-2.14) to 7.14 (range 3.42-10.38)/10.000.000/years; (p < .001).

CONCLUSIONS

PC associates with severe primary hyperparathyroidism and must be suspected if calcium ≥1.77 mmol/l. The prevalence of CDC73 germline mutations in PC and APA in Finland is 6%. PC has distinct histopathological characteristics and its incidence has increased over the past decades.

A registry-based study of thyroid paraganglioma: histological and genetic characteristics

The precise diagnosis of thyroid neoplasias will guide surgical management. Primary thyroid paraganglioma has been rarely reported. Data on prevalence, immunohistochemistry (IHC), and molecular genetics in a systematic series of such patients are pending. We performed a multinational population-based study on thyroid paraganglioma and analyzed prevalence, IHC, and molecular genetics. Patients with thyroid paraganglioma were recruited from the European-American-Head-and-Neck-Paraganglioma-Registry. Demographic and clinical data were registered. Histopathology and IHC were re-investigated. All patients with thyroid paraganglioma underwent molecular genetic analyses of the SDHA, SDHB, SDHC, SDHD, SDHAF2, VHL, RET, TMEM127, and MAX genes. Analyses included Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA) for detection of large rearrangements. Of 947 registrants, eight candidates were initially identified. After immunohistochemical analyses of these eight subjects, 5 (0.5%) were confirmed to have thyroid paraganglioma. IHC was positive for chromogranin, synaptophysin, and S-100 and negative for calcitonin in all five thyroid paragangliomas, whereas the three excluded candidate tumors stained positive for pan-cytokeratin, a marker excluding endocrine tumors. Germline variants, probably representing mutations, were found in four of the five confirmed thyroid paraganglioma cases, two each in SDHA and SDHB, whereas the excluded cases had no mutations in the tested genes. Thyroid paraganglioma is a finite entity, which must be differentiated from medullary thyroid carcinoma, because medical, surgical, and genetic management for each is different. Notably, approximately 80% of thyroid paragangliomas are associated with germline variants, with implications for additional tumors and a potential risk for the family. As opposed to sporadic tumors, surgical management and extent of resection are different for heritable tumors, each guided by the precise gene involved.

[Pheochromocytoma can be an insidious disease]

Pheochromocytoma is a tumor of the chromaffin tissue, originating from the suprarenal medulla and secreting cathecolamines, adrenalin and noradrenalin. Because the symptoms of this rare disease may deceptively resemble those of other diseases, its diagnosis may be delayed. Episodic symptoms are characteristic of pheochromocytoma. In most cases the tumor is curable with surgery, but untreated may lead to sudden death of the patient, or have time to spread. Alpha-blockade is started before the operation. The operations should be concentrated to units specialized in endocrine surgery.