Novel prognostic nomogram for predicting recurrence-free survival in medullary thyroid carcinoma.

AIMS: Recently, there have been attempts to improve prognostication and therefore better guide treatment for patients with medullary thyroid carcinoma (MTC). In 2022, the International MTC Grading System (IMTCGS) was developed and validated using a multi-institutional cohort of 327 patients. The aim of the current study was to build upon the findings of the IMTCGS to develop and validate a prognostic nomogram to predict recurrence-free survival (RFS) in MTC. METHODS AND RESULTS: Data from 300 patients with MTC from five centres across the USA, Europe, and Australia were used to develop a prognostic nomogram that included the following variables: age, sex, AJCC stage, tumour size, mitotic count, necrosis, Ki67 index, lymphovascular invasion, microscopic extrathyroidal extension, and margin status. A process of 10-fold cross-validation was used to optimize the model's performance. To assess discrimination and calibration, the area-under-the-curve (AUC) of a receiver operating characteristic (ROC) curve, concordance-index (C-index), and dissimilarity index (D-index) were calculated. Finally, the model was externally validated using a separate cohort of 87 MTC patients. The model demonstrated very strong performance, with an AUC of 0.94, a C-index of 0.876, and a D-index of 19.06. When applied to the external validation cohort, the model had an AUC of 0.9. CONCLUSIONS: Using well-established clinicopathological prognostic variables, we developed and externally validated a robust multivariate prediction model for RFS in patients with resected MTC. The model demonstrates excellent predictive capability and may help guide decisions on patient management. The nomogram is freely available online at https://nomograms.shinyapps.io/MTC_ML_DFS/.

A Detailed Histologic and Molecular Assessment of the Diffuse Sclerosing Variant of Papillary Thyroid Carcinoma.

Diffuse sclerosing variant papillary thyroid carcinoma (DS-PTC) is characterized clinically by a predilection for children and young adults, bulky neck nodes, and pulmonary metastases. Previous studies have suggested infrequent BRAFV600E mutation but common RET gene rearrangements. Using strict criteria, we studied 43 DS-PTCs (1.9% of unselected PTCs in our unit). Seventy-nine percent harbored pathogenic gene rearrangements involving RET, NTRK3, NTRK1, ALK, or BRAF; with the remainder driven by BRAFV600E mutations. All 10 pediatric cases were all gene rearranged (P = .02). Compared with BRAFV600E-mutated tumors, gene rearrangement was characterized by psammoma bodies involving the entire lobe (P = .038), follicular predominant or mixed follicular architecture (P = .003), pulmonary metastases (24% vs none, P = .04), and absent classical, so-called "BRAF-like" atypia (P = .014). There was no correlation between the presence of gene rearrangement and recurrence-free survival. Features associated with persistent/recurrent disease included pediatric population (P = .030), gene-rearranged tumors (P = .020), microscopic extrathyroidal extension (P = .009), metastases at presentation (P = .007), and stage II disease (P = .015). We conclude that DS-PTC represents 1.9% of papillary thyroid carcinomas and that actionable gene rearrangements are extremely common in DS-PTC. DS-PTC can be divided into 2 distinct molecular subtypes and all BRAFV600E-negative tumors (1.5% of papillary thyroid carcinomas) are driven by potentially actionable oncogenic fusions.

The Prognostic Impact of Extent of Vascular Invasion in Follicular Thyroid Carcinoma.

BACKGROUND: Encapsulated angioinvasive follicular thyroid carcinoma (EAFTC) is associated with an increased risk of distant metastasis and reduced survival compared to minimally invasive follicular thyroid carcinoma (MIFTC). There is controversy regarding the extent of surgery and adjuvant radioactive iodine therapy for angioinvasive follicular thyroid carcinoma when stratified by number of foci of angioinvasion. METHODS: All follicular thyroid carcinoma cases from 1990-2018 were identified from a thyroid cancer database. Primary outcomes were distant metastasis-free survival (DMFS) and disease-specific survival (DSS) with factors of interest being age, gender, tumour size, treatment, foci of angioinvasion and histological subtype. RESULTS: A total of 292 cases were identified; 139 MIFTC, 141 EAFTC and 12 widely invasive follicular thyroid carcinoma (WIFTC). Over a follow-up period of 6.25 years, DMFS was significantly reduced (p < 0.001) with 14.2% (EAFTC) and 50% of WIFTC developing metastasis. The risk of metastasis in EAFTC with ≥ 4 foci of angioinvasion was 31.7% (HR = 5.89, p = 0.004), 6.3% for EAFTC with < 4 foci of angioinvasion (HR = 1.74, p = 0.47), compared to 3.6% MIFTC. Age ≥ 50 years (HR = 4.24, p = 0.005) and tumour size (HR = 1.27, p = 0.014) were significantly associated with increased risk of distant metastasis. DSS was reduced significantly (p < 0.001), with 7.8% EAFTC patients dying of disease. For EAFTC patients, DSS was 96.8% for < 4 foci and 82.6% for ≥ 4 foci of angioinvasion (p = 0.003). CONCLUSION: EAFTC is at increased risk of distant metastasis related to the extent of angioinvasion. Tumours with < 4 foci of angioinvasion should be considered for a total thyroidectomy, particularly in older patients.

Expanding the clinicopathological spectrum of succinate dehydrogenase-deficient renal cell carcinoma with a focus on variant morphologies: a study of 62 new tumors in 59 patients.

Most succinate dehydrogenase (SDH)-deficient renal cell carcinomas (RCCs) demonstrate stereotypical morphology characterized by bland eosinophilic cells with frequent intracytoplasmic inclusions. However, variant morphologic features have been increasingly recognized. We therefore sought to investigate the incidence and characteristics of SDH-deficient RCC with variant morphologies. We studied a multi-institutional cohort of 62 new SDH-deficient RCCs from 59 patients. The median age at presentation was 39 years (range 19-80), with a slight male predominance (M:F = 1.6:1). A relevant family history was reported in 9 patients (15%). Multifocal or bilateral tumors were identified radiologically in 5 patients (8%). Typical morphology was present at least focally in 59 tumors (95%). Variant morphologies were seen in 13 (21%) and included high-grade nuclear features and various combinations of papillary, solid, and tubular architecture. Necrosis was present in 13 tumors, 7 of which showed variant morphology. All 62 tumors demonstrated loss of SDHB expression by immunohistochemistry. None showed loss of SDHA expression. Germline SDH mutations were reported in all 18 patients for whom the results of testing were known. Among patients for whom follow-up data was available, metastatic disease was reported in 9 cases, 8 of whom had necrosis and/or variant morphology in their primary tumor. Three patients died of disease. In conclusion, variant morphologies and high-grade nuclear features occur in a subset of SDH-deficient RCCs and are associated with more aggressive behavior. We therefore recommend grading all SDH-deficient RCCs and emphasize the need for a low threshold for performing SDHB immunohistochemistry in any difficult to classify renal tumor, particularly if occurring at a younger age.

Multimodality Treatment Improves Locoregional Control, Progression-Free and Overall Survival in Patients with Anaplastic Thyroid Cancer: A Retrospective Cohort Study Comparing Oncological Outcomes and Morbidity between Multimodality Treatment and Limited Treatment.

BACKGROUND: Patients with anaplastic thyroid cancer (ATC) have poor overall survival, and the optimal management approach remains unclear. The aim of this study is to evaluate our experience with multimodality (MMT) versus limited treatment (LT) for ATC. PATIENTS AND METHODS: A cohort study of patients with ATC managed in a tertiary referral center was undertaken. The outcomes of MMT were compared with those of LT. The primary outcome measures were locoregional control and progression-free and overall survival. Secondary outcome measures were treatment-related complications and factors associated with improved survival. RESULTS: In total, 59 patients (35 females) with a median age of 73 years (range 39-99 years) and ATC stage IVA (n = 2), IVB (n = 28), or IVC (n = 29) were included. LT was utilized in 25 patients (42%), and 34 cases had MMT. MMT patients had a longer time of locoregional control (18.5 versus 1.9 months; p < 0.001), progression-free survival (3.5 versus 1.2 months; p < 0.001), and overall survival (6.9 versus 2.0 months; p < 0.001) when compared with LT. For patients with stage IVC ATC, locoregional control (p = 0.03), progression-free survival (p < 0.001), and overall survival (p < 0.001) were superior in the MMT cohort compared with LT. MMT had more treatment-related complications than LT (p < 0.001). An Eastern Cooperative Oncology Group performance status < 2 (HR 0.30; p = 0.001) and MMT (HR 0.35; p = 0.008) were associated with improved overall survival. CONCLUSION: MMT is likely to improve locoregional control, progression-free survival, and overall survival in selected ATC patients including stage IVC tumors but comes with a greater complication risk.

Tailored first-line and second-line CDK4-targeting treatment combinations in mouse models of pancreatic cancer.

OBJECTIVE: Extensive molecular heterogeneity of pancreatic ductal adenocarcinoma (PDA), few effective therapies and high mortality make this disease a prime model for advancing development of tailored therapies. The p16-cyclin D-cyclin-dependent kinase 4/6-retinoblastoma (RB) protein (CDK4) pathway, regulator of cell proliferation, is deregulated in PDA. Our aim was to develop a novel personalised treatment strategy for PDA based on targeting CDK4. DESIGN: Sensitivity to potent CDK4/6 inhibitor PD-0332991 (palbociclib) was correlated to protein and genomic data in 19 primary patient-derived PDA lines to identify biomarkers of response. In vivo efficacy of PD-0332991 and combination therapies was determined in subcutaneous, intrasplenic and orthotopic tumour models derived from genome-sequenced patient specimens and genetically engineered model. Mechanistically, monotherapy and combination therapy were investigated in the context of tumour cell and extracellular matrix (ECM) signalling. Prognostic relevance of companion biomarker, RB protein, was evaluated and validated in independent PDA patient cohorts (>500 specimens). RESULTS: Subtype-specific in vivo efficacy of PD-0332991-based therapy was for the first time observed at multiple stages of PDA progression: primary tumour growth, recurrence (second-line therapy) and metastatic setting and may potentially be guided by a simple biomarker (RB protein). PD-0332991 significantly disrupted surrounding ECM organisation, leading to increased quiescence, apoptosis, improved chemosensitivity, decreased invasion, metastatic spread and PDA progression in vivo. RB protein is prevalent in primary operable and metastatic PDA and may present a promising predictive biomarker to guide this therapeutic approach. CONCLUSION: This study demonstrates the promise of CDK4 inhibition in PDA over standard therapy when applied in a molecular subtype-specific context.

Pathology and genetics of phaeochromocytoma and paraganglioma.

Phaeochromocytoma and paraganglioma (PHEO/PGL) are rare tumours with an estimated annual incidence of 3 per million. Advances in molecular understanding have led to the recognition that at least 30-40% arise in the setting of hereditary disease. Germline mutations in the succinate dehydrogenase genes SDHA, SDHB, SDHC, SDHD and SDHAF2 are the most prevalent of the more than 19 hereditary genetic abnormalities which have been reported. It is therefore recommended that, depending on local resources and availability, at least some degree of genetic testing should be offered to all PHEO/PGL patients, including those with clinically sporadic disease. It is now accepted that that all PHEO/PGL have some metastatic potential; therefore, concepts of benign and malignant PHEO/PGL have no meaning and have been replaced by a risk stratification approach. Although there is broad acceptance that certain features, including high proliferative activity, invasive growth, increased cellularity, large tumour nests and comedonecrosis, are associated with an increased risk of metastasis, it remains difficult to predict the clinical behaviour of individual tumours and no single risk stratification scheme is endorsed or in widespread use. In this review, we provide an update on advances in the pathology and genetics of PHEO/PGL with an emphasis on the changes introduced in the WHO 2017 classification of endocrine neoplasia relevant to practising surgical pathologists.

Anaplastic thyroid cancer: A review of recent evidence and summary of an Australian institutional protocol.

Anaplastic thyroid cancer (ATC), a rare and highly aggressive malignancy, is characterized by an exceptionally poor prognosis, where the majority of patients present with extensive local invasion and/or distant metastases. 20-30% of ATCs harbor the BRAF-V600E mutation. Neoadjuvant BRAF-targeted therapy may have the potential to downstage and facilitate surgical resection for patients with locally advanced and unresectable primary tumors with BRAF mutation and may convey a survival advantage in those with metastatic disease. There is emerging evidence to support the use of other targeted agents, including multikinase inhibitors, as well as the incorporation of immunotherapy into the treatment regimen. Rapid molecular and pathological diagnosis and expert multidisciplinary discussion at specialized treatment centers are critical to expedite investigations and initiate treatment for this complex and rapidly progressive disease.

A Critical Assessment of Diagnostic Criteria for the Tall Cell Subtype of Papillary Thyroid Carcinoma-How Much? How Tall? And When Is It Relevant?

Tall cell papillary thyroid carcinoma (TC-PTC) is considered adverse histology. However, previous studies are confounded by inconsistent criteria and strong associations with other adverse features. It is therefore still unclear if TC-PTC represents an independent prognostic factor in multivariate analysis and, if it does, what criteria should be employed for the diagnosis. We retrospectively reviewed 487 PTCs from our institution (where we have historically avoided the prospective diagnosis of TC-PTC) for both the height of tall cells (that is if the cells were two, or three, times as tall as wide) and the percentage of tall cells. On univariate analysis, there was significantly better disease free survival (DFS) in PTCs with no significant tall cell component (< 30%) compared to PTCs with cells two times tall as wide (p = 0.005). The proportion of tall cells (30-50% and > 50%) was significantly associated with DFS (p = 0.012). In a multivariate model including age, size, vascular space invasion, and lymph node metastasis, the current WHO tall cell criteria, met by 7.8% of PTCs, lacked statistical significance for DFS (p = 0.519). However, in the subset of tumours otherwise similar to the American Thyroid Association (ATA) guidelines low-risk category, WHO TC-PTC demonstrated a highly significant reduction in DFS (p = 0.004). In contrast, in intermediate to high-risk tumours, TC-PTC by WHO criteria lacked statistical significance (p = 0.384). We conclude that it may be simplistic to think of tall cell features as being present or absent, as both the height of the cells (two times versus three times) and the percentage of cells that are tall have different clinical significances in different contexts. Most importantly, the primary clinical significance of TC-PTC is restricted to PTCs that are otherwise low risk by ATA guidelines.

The Presence of Typical "BRAFV600E-Like" Atypia in Papillary Thyroid Carcinoma is Highly Specific for the Presence of the BRAFV600E Mutation.

Papillary thyroid carcinomas (PTCs) are driven by a variety of molecular abnormalities including BRAF, RAS, ALK, RET, and NTRK alterations. PTCs driven by the BRAFV600E mutation, or tumours which demonstrate a similar gene expression profile to PTCs driven by this mutation, have been reported to demonstrate specific morphological features sometimes termed "BRAFV600E-like" atypia. BRAFV600E-like atypia is characterised by a well-developed papillary architecture, infiltrative growth, marked nuclear clearing, prominent intranuclear pseudoinclusions, abundant eosinophilic cytoplasm, and scattered psammoma bodies. We sought to investigate the sensitivity and specificity of these morphological features for the presence of BRAFV600E mutation in PTCs as determined by mutation specific immunohistochemistry. An unselected cohort of 495 PTCs was reviewed by a single pathologist and categorised into three groups: typical BRAFV600E-like atypia (145 cases, 29%), possible BRAFV600E-like atypia (166 cases, 33%) and little/no BRAFV600E-like atypia (184 cases, 37%). The specificity and sensitivity of typical BRAFV600E-like atypia for the BRAFV600E mutation was 97.2% and 44.3%, respectively. When typical and possible BRAFV600E-like atypia were analysed together, the specificity was 70.6% and the sensitivity was 81.7%. In the morphologically little/no BRAFV600E-like atypia group, 58 cases (31.5%) had a BRAFV600E mutation. We conclude that typical BRAFV600E-like atypia is highly specific for the presence of the BRAFV600E mutation; however, the absence of BRAFV600E-like atypia does not exclude this mutation.

The Right Treatment Strategy for the Right Patient: A Biomarker-Driven Approach to Neoadjuvant vs. Surgery-First Management of Resectable and Borderline Resectable Pancreatic Cancer.

The genomic heterogeneity of pancreatic ductal adenocarcinoma (PDAC) is becoming increasingly appreciated. We aimed to evaluate the ability of a triple biomarker panel (S100A4, Ca-125, and mesothelin) to predict: (i) genetic PDAC subtypes; (ii) clinical phenotypes; and (iii) the optimal treatment strategy (neoadjuvant vs. surgery-first) in resectable and borderline resectable PDAC. Patients who underwent resection for resectable and borderline resectable PDAC were included from one single-institutional cohort and one multi-institutional cohort from the Australian Pancreatic Genome Initiative (APGI). Tumors were immunohistochemically evaluated for S100A4, Ca-125, and mesothelin, and a subset from the APGI cohort underwent RNA sequencing. This study included 252 and 226 patients from the single institution and the APGI cohorts, respectively. Triple-negative biomarker status correlated with non-squamous PDAC genotypes (p = 0.020), lower rates of distant recurrence (p = 0.002), and longer median overall survival (mOS) with the surgery-first approach compared with neoadjuvant treatment (33.3 vs. 22.2 mths, p = 0.038) in resectable PDAC. In contrast, the triple-positive disease was associated with longer mOS with neoadjuvant treatment compared with the surgery-first approach (29.5 vs. 13.7 mths, p = 0.021) in resectable and borderline resectable PDAC. In conclusion, the triple biomarker panel predicts genetic PDAC subtypes, clinical phenotypes, and optimal treatment strategies in resectable and borderline resectable PDAC.

Purely extradural spinal meningioma: A case report and literature review.

BACKGROUND: Purely extradural spinal meningiomas (ESMs) are exceptionally rare and are often incorrectly diagnosed as metastases, hematological malignancies, or schwannomas. Here, we report a 66-year-old female who presented with an isolated extradural ESM. CASE DESCRIPTION: A 66-year-old female presented with a 2.5-year history of a progressive paraparesis (i.e. T7 level) associated with a T5 sensory level. The MR showed a heterogeneously enhancing lesion circumferentially involving the spinal cord from T3 to T5, with left-sided T4/5 foraminal extension. Following a Simpson Grade 2 resection, the patient rapidly recovered full neurological function. CONCLUSION: The vast majority of the rarely encountered purely ESM are benign. Although gross total resection is optimal, additional adjunctive treatments are available for those treated with subtotal resections.

PD-L1 Is Preferentially Expressed in PIT-1 Positive Pituitary Neuroendocrine Tumours.

Pituitary neuroendocrine tumours (PitNETs) cause lifelong morbidity, some requiring extensive surgical intervention, radiotherapy, or chemotherapy. A small percentage still cause debilitating disease, resistant to standard treatments, and may benefit from novel therapies. We assessed PD-L1 expression in a large cohort of PitNETs to investigate whether immunotherapy could represent a rational therapeutic choice. Unselected PitNETs undergoing surgical resection were reclassified according to the WHO 2017 system and underwent PD-L1 immunohistochemistry (clone SP263) in tissue microarray format. Membranous expression was scored as 0 (no expression), 1+ (< 50% expression) and 2+ (> 50% expression). A total of 265 PitNETs underwent PD-L1 immunohistochemistry. Prominent non-specific cytoplasmic staining was noted making assessment of true membrane expression difficult. Allowing for this, 40 of 264 (15%) PitNETs demonstrated strong staining (> 50% of neoplastic cells positive). These included 5/10 (50%) somatotrophs, 7/17 (41%) lactotrophs, 2/5 (40%) mammosomatotrophs, 4/8 (50%) mixed somatotroph-lactotrophs, 3/5 (60%) PIT-1 positive plurihormonal tumours with TSH expression, 10/28 (36%) of PIT-1 positive plurihormonal tumours, and 4/10 (40%) of PIT-1 positive tumours with no hormonal expression. Only 2/32 (6%) transcription factor triple negative, hormone negative tumours, 5/113 (4%) of gonadotrophs, and 0/6 thyrotrophs or 0/30 corticotrophs showed significant staining. We conclude that PD-L1 expression is common in somatotrophs, lactotrophs, and PIT-1 positive plurihormonal PitNETs but rare in transcription factor negative, hormone negative PitNETs, gonadotrophs, and corticotrophs. If the therapeutic role of immunotherapy is to be explored in PitNETs, it may be that it is of most benefit in the PD-L1 high subgroup.

Prophylactic central lymph node dissection informs the decision of radioactive iodine ablation in papillary thyroid cancer.

BACKGROUND: Prophylactic central lymph node dissection (CLND) in papillary thyroid cancer (PTC) is controversial. We aimed to investigate if prophylactic CLND aids risk stratification and contributes to the decision for postoperative RAI ablation. METHODS: Patients undergoing thyroidectomy for PTC and prophylactic CLND were identified from an endocrine surgical unit database. Pathology reports where reviewed for number and size of lymph nodes and patients stratified by risk according to the ATA guidelines. RESULTS: 426 patients were identified with PTC ≤4 cm and prophylactic CLND. 96 patients (23%) had central lymph node metastasis (CLNM) that qualified them for the intermediate risk group. In 17 patients (4%), the CLNM data led to upgrading independently of other histopathological characteristics. Correcting for multiple variables, CLNM was an independent factor contributing to RAI treatment. CONCLUSION: Prophylactic CLND provides information to aid the selection of RAI ablation independent of primary cancer histology for risk stratification in 4% of patients. This benefit should be carefully balanced with the risk of CLND and patient treatment choice when deciding on management of PTC ≤4 cm.

Hereditary Parathyroid Disease: Sometimes Pathologists Do Not Know What They Are Missing.

Parathyroid gland excision specimens are common and sometimes underestimated cases that many surgical pathologists encounter regularly. In the vast majority of cases, these will be spot diagnoses of sporadic primary parathyroid adenomas or, perhaps, hyperplasias commonly in the setting of renal failure. However, a small but significant number of parathyroid gland excisions may be due to heritable disease. In most cases, hereditary disease is suspected by the referring clinicians. Nevertheless, a subset of these are undetected which is significant, particularly in the setting of the multiple endocrine neoplasia (MEN), and the hyperparathyroidism jaw tumour (HPT-JT) syndromes. There have been recent advances in recognition of the morphological and immunohistochemical characteristics of these tumours and hyperplasias. While hereditary kindreds are over-represented at specialist referral centres, with awareness of the characteristic clinical and morphological features, the general surgical pathologist is frequently able to suggest the possibility of hereditary parathyroid disease. We therefore provide a succinct guide for pathologists to increase the recognition of hereditary parathyroid disease.

Utility of GATA-3 Expression in the Analysis of Pituitary Neuroendocrine Tumour (PitNET) Transcription Factors.

With the introduction of the WHO 2017 classification of endocrine neoplasms, the use of the pituitary transcription factors PIT-1, Tpit and SF-1 has become the standard of care. However, immunohistochemistry for these transcription factors is not available in all institutions, and their reliability has been questioned. We read with interest the findings of Mete et al. that GATA-3 expression was detected in some pituitary neuroendocrine tumours (PitNET). We therefore sort to validate this in our large cohort of PitNETs. We searched the database of Royal North Shore Hospital for PitNETs between 1998 and 2012, constructed a tissue microarray and reclassified these entities based on their expression for PIT-1, Tpit and SF-1. We then scored the expression of GATA-3 immunohistochemistry on a scale of 0-2, where 0 was no staining, 1 was patchy or weak staining and 2 was strong and diffuse staining. 265 of 346 tumours were able to be classified into a specific tumour subtype, and 263 tumours had tissue available for GATA-3 immunohistochemistry. 89% of gonadotrophs and 93% of triple-negative tumours with expression for luteinising hormone and follicle-stimulating hormone were positive for GATA-3. In the triple-negative group, GATA-3 was positive in 1 mammosomatotroph and 80% of tumours with thyroid-stimulating hormone expression. In the triple-negative hormone-negative group, 21 of 33 tumours were positive (64%). The results demonstrate that GATA-3 is a useful marker to supplement the existing pituitary transcription factors, albeit slightly less sensitive and specific than previously reported. GATA-3 may be employed in addition to the current array of immunohistochemical transcription factors, especially in the resource poor setting. However, given its potential cross-reactivity with other entities of the Sella, positive staining should be interpreted with caution and in the morphological and clinical context.