Non-functioning pancreatic neuroendocrine tumors (NF-pNETs) show a variable prognosis. Despite 40–60
A substantial fraction (60-85%) of hereditary primary hyperparathyroidism (hPHPT) lacks an identifiable genetic etiology. We describe fumarate hydratase (FH) mutations as a potential cause of hPHPT, expanding the phenotypic spectrum of FH deficiency tumor predisposition syndromes. In an index patient who presented with asymptomatic hypercalcemia and a chief-to-transitional cell-dominant parathyroid adenoma, whole-exome sequencing revealed two unique heterozygous FH variants (germline p.Gln376fs*2; somatic p.Pro503_Lys504dup). Functional inactivation of FH was supported by diffuse nuclear and cytoplasmic 2-succinocysteine immunoreactivity and elevated fumarate/malate ratio in tumor tissue. This individual did not show classic HLRCC manifestations. Preserved FH protein expression suggested residual enzymatic activity, which may account for an attenuated phenotype. To assess broader relevance, no additional patients with bona fide FH-deficient parathyroid adenoma were identified among 130 individuals with suspected hPHPT of unknown etiology evaluated at our institute. In a complementary cohort of 11 patients with pheochromocytoma/paraganglioma syndrome harboring pathogenic germline heterozygous FH variants, one female (FH p.Thr234Ala) presented with multi-gland disease requiring parathyroidectomy at age 40 years, features suspicious for hPHPT. These findings support fumarate hydratase deficiency as a plausible etiology for a subset of parathyroid adenomatous disease. Thus, consideration of parathyroid function surveillance in patients with fumarate hydratase deficiency tumor predisposition syndromes may be warranted. CLINICAL TRIAL NUMBER: NCT04969926.
Adrenocortical carcinoma (ACC) is a rare malignancy with high recurrence rates. Circulating tumor DNA (ctDNA) is a minimally invasive, blood-based biomarker with multiple oncologic applications. The role of ctDNA in ACC care remains understudied. This retrospective, single-institution, study evaluated real-world use of ctDNA testing in patients with ACC and its correlation with imaging-based tumor burden. Patients with ACC (≥ 18 years) who underwent ctDNA testing via a clinically validated, personalized, tumor-informed assay (Signatera™, Natera) during their disease course were reviewed, and clinical data were obtained from the medical records. ctDNA results were tested for association with disease status and tumor burden determined by concurrent imaging and clinical evaluation. Twenty patients (55
Renal well-differentiated neuroendocrine tumors (RenNETs) are rare primary renal neoplasms with enigmatic histogenesis. To define the molecular features of RenNETs and clarify their relationship to neuroendocrine tumors (NETs) from other sites, we performed whole-exome DNA sequencing and transcriptomic profiling on six RenNETs. In one case, adjacent non-neuroendocrine cystic epithelium and a regional lymph node metastasis were independently analyzed. RenNETs demonstrated a low-to-intermediate tumor mutational burden and recurrent copy number alterations, including losses involving chromosomes 3, 11, and 18 and gains involving chromosomes 1, 2, 8, and 14, partially overlapping those reported in gastroenteropancreatic NETs, in the absence of alterations in canonical NET-associated driver genes. RNA sequencing revealed marked upregulation of genes involved in neuroendocrine differentiation, peptide processing, and pancreatic beta cell function, accompanied by loss of renal lineage markers, indicating a neuroendocrine transcriptional program distinct from other primary renal neoplasms. RenNETs showed heterogeneous activation of hormone related transcriptional programs, rather than conforming to a discrete EC-cell or L-cell signature. Immunohistochemistry confirmed strong membranous expression of somatostatin receptor 2A (SSTR2A) in all cases, supporting established imaging and therapeutic paradigms used for NETs. Notably, two RenNETs were associated with adjacent CDX2-positive epithelial-lined cysts with intestinal differentiation. In one case, a shared somatic mutation was identified across the epithelial cyst, the adjacent RenNET, and a nodal metastasis, providing genetic evidence of a common clonal origin and implicating gastrointestinal-type epithelium as a potential precursor lesion in a subset of cases. Features supporting teratomatous origin, such as chromosome 12p gains or other germ cell tumor elements, were not identified. Together, these findings demonstrate that RenNETs exhibit convergent transcriptomic and phenotypic neuroendocrine programs, along with partial copy number overlap, with well-differentiated gastroenteropancreatic NETs, and support a model in which RenNETs may arise from developmentally displaced or aberrantly differentiated epithelial precursors with gastrointestinal-type differentiation, although this hypothesis requires validation in larger cohorts.
Multifocal fibrosing thyroiditis (MFT) is a poorly understood condition characterized by multiple fibrotic scar-like lesions with paucicellular core and peripheral follicular cell atypia. Described by Dr. Rosai in 1990 in consultation cases, MFT has received limited attention due to its perceived rarity. To define its prevalence and clinicopathologic features in the routine practice, consecutive thyroid resections were analyzed from the archives of two medical institutions in Italy and Portugal. Among 1,736 resections 27 MFT were identified (1.56
Oncocytic thyroid carcinomas are characterized by a unique chromosomal landscape and frequent resistance to radioactive iodine therapy, underscoring the need for improved molecular characterization. Although ALK rearrangements, particularly STRN::ALK fusions, have been described in thyroid carcinomas, their biological and clinical significance in oncocytic thyroid neoplasms remains unclear. This study investigated STRN exon 3-ALK exon 20-derived transcripts in 56 oncocytic thyroid neoplasms using RT-PCR, followed by cloning and Sanger sequencing of positive cases. Transcript-positive cases were further evaluated by fluorescence in situ hybridization (FISH), immunohistochemistry (IHC), and in silico structural modeling. STRN::ALK-derived transcripts were detected in 9 of 56 tumors; however, their frequency reflected the combined detection of distinct transcript architectures. Only 2 of 56 tumors (3.6%) harbored canonical in-frame STRN::ALK fusions, whereas 7 of 56 tumors (12.5%) contained noncanonical out-of-frame variants. Although ALK rearrangement by FISH was confirmed in all transcript-positive tumors irrespective of transcript architecture, detectable ALK protein expression by IHC was observed only in tumors harboring canonical in-frame fusions, whereas all noncanonical variants lacked detectable ALK protein expression. Structural modeling was concordant with these observations, suggesting preservation of kinase-domain features in canonical fusions and predicted disruption in noncanonical variants. Overall, STRN::ALK transcripts in oncocytic thyroid neoplasms exhibit marked architectural heterogeneity with distinct ALK protein expression patterns. ALK FISH-positive/IHC-negative cases should be interpreted cautiously, as they may not represent biologically equivalent ALK-driven neoplasia, with uncertain therapeutic relevance. Integrated molecular and protein-level assessment may support interpretation of ALK alterations in oncocytic thyroid neoplasms.
Current data on neuroendocrine tumors (NETs) of the gallbladder and cystic duct (GB-NETs) are highly limited, and the available evidence, largely derived from cancer registry data, suggests that these tumors exhibit a substantially more aggressive clinical behavior than NETs arising at other anatomical sites. We analyzed 26 GB-NETs. Female-to-male ratio: 1.9:1; median age: 50 years. They were typically incidental small (median: 0.8 cm, range: 0.08–2.3 cm) tumors, with 81
The mechanisms underlying how adrenocortical carcinoma (ACC) progresses into a metastatic and lethal disease remain poorly understood. To address this, we performed comprehensive genomic analyses to delineate the evolutionary trajectory of advanced ACC. Fresh frozen tumour samples (n = 29) were obtained from nine patients, all of whom had matched primary and relapse specimens, including recurrent (n = 4) and metastatic (n = 11) lesions. In four patients, multiple primary and metastatic samples were available, enabling detailed evolutionary comparisons. All tumours underwent whole-genome sequencing, RNA sequencing, and DNA methylation profiling. Our analyses revealed that seven of nine patients exhibited global loss of heterozygosity (LOH) often followed by whole-genome doubling, resulting in copy-neutral LOH. SNP-based analyses indicated that these alterations occurred as a single catastrophic event that was conserved across all matched samples within each patient, suggesting that this event constitutes a truncal feature of the evolutionary tree. These results support a model in which chromosomal aneuploidy is important in ACC tumourigenesis, potentially distinguishing carcinomas from benign adrenal adenomas. This may explain the rarity of adenoma-to-carcinoma transformation and suggest a diagnostic and therapeutic relevance of chromosomal instability in ACC.
Pulmonary neuroendocrine tumors (NETs) include typical and atypical carcinoids, corresponding to low- and intermediate-grade malignancies. Integration of necrosis, mitotic count per 2 mm² (MC), and Ki-67 index, a desirable criterion in the current WHO scheme, may enable a classification framework beyond conventional histology. We used a clustering method for mixed-type data, including necrosis, MC and Ki-67 index, on a single-institution cohort of 358 typical and 125 atypical carcinoids with long-term follow-up. An external validation series of 259 additional carcinoids was used. A three-cluster solution was selected, yielding a tiered prognostic stratification model, that included NETG1 (383 cases; mean MC: 0.7; necrosis: 8.1
Thyroid nodules with indeterminate cytology represent a clinical challenge owing to uncertain malignancy risk, often leading to diagnostic surgery. Molecular testing has emerged as a promising adjunct to improve risk stratification and guide surgical decision-making. However, the clinical utility and impact of different molecular platforms remain debated. The present study evaluates the impact of molecular testing on surgical decision-making in indeterminate thyroid nodules and compares outcomes between first- and second-generation molecular platforms. A PRISMA-guided systematic review and meta-analysis identified 132 studies including 66,448 thyroid nodules, of which 30,292 (45.6
Well-differentiated neuroendocrine tumors, grade 3 (NETs G3) of the digestive system are high-grade neuroendocrine neoplasms characterized by well-differentiated neuroendocrine morphology and high proliferative activity. Their molecular identity and therapeutic vulnerabilities remain incompletely defined. We performed a transcriptomic analysis and a comprehensive genomic profiling of 40 cases, including 26 NETs G3, 8 NETs G1/G2, and 6 neuroendocrine carcinomas (NECs). Targeted sequencing assessed alterations at both the DNA and RNA level, and gene expression profiling was conducted using a targeted immune-oncology panel. NETs G3 retained recurrent alterations in chromatin-regulatory genes characteristic of well-differentiated tumors and largely lacked the consistent TP53 and RB1 inactivation typical of NECs. Transcriptomic and genomic analysis demonstrated separation of NECs from NETs, with NETs G3 partially overlapping with NETs G1/G2 supporting a model of molecular relatedness. However, when compared with NETs G1/G2, NETs G3 showed upregulation of extracellular matrix remodeling, metabolic reprogramming, and cytokine signaling pathways. NETs G3 were heterogeneous in terms of number of genomic alterations per case and involved genes. A distinctive genomic feature was the predominance of large-segment copy-number losses, frequently involving chromatin-regulatory regions on chromosomes X and 10. Potentially targetable alterations were detected in up to 25% of NETs G3. Analysis of immune microenvironment supported a poorly inflamed tumor status, with individual cases harboring microsatellite instability or enrichment in tumor-infiltrating lymphocytes potentially amenable to immunotherapy.
Pituitary neuroendocrine tumors (PitNETs) are common sellar neoplasms and represent a major component of routine pituitary pathology. In the 2022 World Health Organization (WHO) Classification, transcription factor-defined lineage assignment is central to diagnosis. However, lineage-related morphologic information on routine hematoxylin and eosin (H&E)-stained whole-slide images (WSIs) has not been systematically characterized. We developed an attention-guided graph neural network to predict PitNET lineage directly from H&E-stained WSIs and to identify regions prioritized for classification. Consecutive patients who underwent surgical resection for PitNETs at Beijing Tiantan Hospital between 2021 and 2025 were included. In the internal hold-out set, the five fold-specific models achieved a mean F1-score of 92.78% and a mean balanced accuracy of 94.84%. In a temporally independent validation cohort, the final model achieved an F1-score of 87.64% and a balanced accuracy of 89.48%. Performance varied across lineages and histomorphologic subtypes, and the most common error pattern was misassignment of PIT-1 and T-PIT tumors to SF-1. Attention maps predominantly highlighted tumor-rich regions. Quantitative cell-level morphometry supported lineage-associated patterns, including larger cell and nuclear sizes in PIT-1 tumors, more elongated nuclei in SF-1 tumors, and higher cellular density with reduced intercellular spacing in T-PIT tumors. In six cases with multiple synchronous PitNETs of distinct lineages, patch-level prediction maps corresponded closely to transcription factor immunohistochemistry. In a small exploratory subset with available DNA methylation data, methylation classifier results were concordant with model predictions in 11 of 15 cases and with routine histopathologic diagnoses in 8 of 15 cases. These findings indicate that routine H&E-stained WSIs contain learnable morphologic information related to PitNET lineage. Attention-guided spatial modeling provides an interpretable framework for characterizing lineage-associated patterns in PitNETs.
The clinical behavior and molecular underpinnings of rare cases of poorly differentiated thyroid carcinoma (PDTC) diagnosed in young adults are not established. We evaluated 13 cases of PDTC in adult patients ≤ 45 years of age. The median age at diagnosis was 40 years (range 27 – 45 years). The median tumor size was 3.7 cm. The median mitotic count was 6 per 2 mm2. Necrosis was present in 7 (54
Thyroid tumors with questionable capsular invasion (CI) or angioinvasion (AI) pose diagnostic and management challenges. The World Health Organization (WHO) recognizes these borderline entities as follicular tumors of uncertain malignant potential (FT-UMP) or well-differentiated tumors of uncertain malignant potential (WDT-UMP). We have conducted a retrospective, single-center study of all thyroid tumors diagnosed as UMP (2005–2025). Of 534 tumors initially labeled “uncertain malignant potential,” application of exclusion criteria yielded 324 tumors from 318 patients with questionable CI and/or AI. Clinicopathological characteristics, molecular testing data, postoperative laboratory values, imaging, and outcomes were analyzed. UMP was diagnosed in 0.5
The aim of this study was to assess whether there is sufficient evidence to recommend a change in the classification of pulmonary tumors currently classified as “carcinoid” tumors to instead apply a system similar to that used for well-differentiated gastrointestinal and pancreatic neuroendocrine tumors (NETs) using the Ki67 proliferation index (PI). We retrospectively reviewed 124 cases of pulmonary NETs (“typical carcinoids” (TC) and “atypical carcinoids” (AC)) diagnosed at the University Hospitals Cleveland Medical Center between 2019 and 2025. Demographic, clinical, and pathology data were collected, including mitotic counts, necrosis, and Ki67 PI assessed in biopsy, resection, and metastatic specimens. Tumors were graded as G1 (≤ 3
Primary aldosteronism (PA) is the leading cause of endocrine hypertension. With the development of highly specific human aldosterone synthase (CYP11B2) antibodies for immunohistochemistry (IHC), the presence of microscopic subcapsular foci of CYP11B2-postive cells – now termed aldosterone-producing micronodules (APM) – has been documented in normal and PA adrenal glands, however, there continues to be debate regarding the role of APM in the pathogenesis of PA. In this study, CYP11B2 IHC-guided targeted next-generation sequencing (NGS) was utilized to characterize the frequency and spectrum of somatic aldosterone-driver mutations in APM identified within adrenal glands from deceased renal donors and patients with primary aldosteronism (PA). 59 subjects were enrolled (31 deceased renal donors and 28 PA patients), 173 APM were collected using CYP11B2-guided IHC (65 APM from 31 deceased renal donors and 108 APM from 28 PA patients), and NGS data was successfully obtained for 131 APM (51 APM from 31 deceased renal donors and 80 APM from 28 PA patients). Importantly, NGS identified aldosterone-driver mutations in a significantly higher proportion of APM from PA patients relative to deceased renal donors (71.3
EC-cell familial small intestine neuroendocrine tumors (EC-cell F-SINET) are a recently described but poorly characterized entity. We aimed to describe their clinical and pathological features, and to compare them to patients with a sporadic form (EC-cell S-SINET). We constituted a nationwide cohort including (retrospectively patients diagnosed before 2012 and prospectively from 2012 to 2022) all patients with F-SINET (histologically proven SINET in ≥ 2 first or second-degree relatives) managed in the French GTE-RENATEN network. Clinical and pathological data were described and compared to the GTE-RENATEN population-based cohort including 2460 patients with EC-cell S-SINET using multivariable logistic regression. The survival impact of EC-cell F-SINET was explored using Cox proportional hazard analyses. We included 92 patients with EC-cell F-SINET from 47 families. Median age at diagnosis was 60.4 years. Among these patients, 22
Adrenal lesions often occur in patients with multiple endocrine neoplasia type 1 (MEN1), mostly adrenal cortical adenomas (ACAs), although the frequency of adrenal cortical carcinomas (ACCs) is higher than in the general population. The coexistence of benign and malignant masses has seldom been documented, leaving open the question of ACC progression from benign forms. We report a comprehensive genetic characterization of three adrenal cortical tumor samples obtained from a familial MEN1 patient, operated for the rapid progression of an initially stable nonfunctional adrenal incidentaloma. Histologically, the tumor consisted of a small ACA contiguous to a large ACC, which subsequently relapsed. Exome sequencing of ACC, ACA and recurrence evidenced a MEN1 loss of heterozygosity (LOH) in ACC but not in ACA, where, however, a second hit driven by alternative mechanisms could not be excluded. The majority of the ACA variants were found to co-occurred in ACC (n = 36/42) and were benign, except for two of unknown significance in KANK1 and REN genes, described as associated with renal cancer. Among variants shared between ACC and its recurrence (n = 69), 11 were Tier III, while 2 affecting TP53 and NF1 genes were pathogenic. Bioinformatic clonal evolution analysis identified one clone − characterized by TP53 and NF1 mutations − absent in ACA but present in ACC and recurrence, as well as 2 clones shared between ACA and ACC but lost in the recurrence. In conclusion, comparative Whole Exome Sequencing (WES) analysis of three adrenal tumors in a MEN1 patient suggests a possible relationship between malignant and benign lesions occurring in MEN1 patients, without, however, demonstrating any causal adenoma-to-carcinoma progression driven by MEN1 LOH. Overall, these data further suggest an increased risk of MEN1 patients to develop adrenocortical malignancy.
Mutations in RAS proto-oncogenes (NRAS, HRAS, KRAS) are common in thyroid nodules, though their prognostic significance remains unclear. This retrospective study analyzed 354 thyroid nodules from 346 patients (2018–2023) to investigate the clinical and pathological implications of isolated RAS mutations and RAS with co-occurring genetic alterations. Isolated RAS mutations were found in 41.0
