Total hysterectomy versus radical hysterectomy in neuroendocrine cervical cancer: a SEER-database analysis.

PURPOSE: We conducted this study to evaluate the efficacy of total hysterectomy versus radical hysterectomy in the treatment of neuroendocrine cervical cancer (NECC). METHODS: Eligible NECC patients were identified from the Surveillance, Epidemiology and End Results (SEER) database. Demographic characteristics, clinical treatment and survival of the patients were collected. The overall survival (OS) and cancer-specific survival (CSS) were estimated by Kaplan-Meier analysis with log-rank test. RESULTS: A total of 286 patients were included, with 104 patients undergoing total hysterectomy and 182 patients undergoing radical hysterectomy. The 5-year OS were 50.8% in the total hysterectomy group and 47.5% in the radical hysterectomy group (p = 0.450); and the corresponding 5-year CSS were 51.6% and 49.1% (p = 0.494), respectively. Along with surgery, radiotherapy was given to 49.0% of patients in the total hysterectomy group and 50.5% in the radical hysterectomy group; and chemotherapy was administered to 77.9% of patients in the total hysterectomy group and 85.7% in the radical hysterectomy group. Unexpectedly, in patients who received adjuvant radiotherapy with or without chemotherapy, the OS was superior in the total hysterectomy group compared with the radical hysterectomy group (p = 0.034). While in patients who received chemotherapy alone and those who received neither radiotherapy nor chemotherapy, the OS still remained comparable between the total hysterectomy and radical hysterectomy group. CONCLUSION: Compared with radical hysterectomy, total hysterectomy was not associated with compromised survival prognosis in patients with NECC. Total hysterectomy has the potential to be a surgical alternative in the multimodal management of NECC.

Time Kinetics and prognosis roles of calcitonin after surgery for medullary thyroid carcinoma.

BACKGROUND: Medullary thyroid carcinoma (MTC) is a malignant tumor with low incidence. Currently, most studies have focused on the prognostic risk factors of MTC, whatever, time kinetic and risk factors related to calcitonin normalization (CN) and biochemical persistence/recurrence (BP) are yet to be elucidated. METHODS: A retrospective study was conducted for 190 MTC patients. Risk factors related to calcitonin normalization (CN) and biochemical persistence/recurrence (BP) were analyzed. The predictors of calcitonin normalization time (CNT) and biochemical persistent/recurrent time (BPT) were identified. Further, the prognostic roles of CNT and BPT were also demonstrated. RESULTS: The 5- and 10-year DFS were 86.7% and 70.2%, respectively. The 5- and 10-year OS were 97.6% and 78.8%, respectively. CN was achieved in 120 (63.2%) patients, whereas BP was presented in 76 (40.0%) patients at the last follow up. After curative surgery, 39 (32.5%) and 106 (88.3%) patients achieved CN within 1 week and 1 month. All patients who failed to achieve CN turned to BP over time and 32/70 of them developed structural recurrence. The median time of CNT and BPT was 1 month (1 day to 84 months) and 6 month (3 day to 63months), respectively. LNR > 0.23 and male gender were independent predictors for CN and BP. LNR > 0.23 (Hazard ratio (HR), 0.24; 95% CI,0.13-0.46; P < 0.01) and male gender (HR, 0.65; 95% CI, 0.42-0.99; P = 0.045) were independent predictors for longer CNT. LNR > 0.23 (HR,5.10; 95% CI,2.15-12.11; P < 0.01) was still the strongest independent predictor followed by preoperative serum Ctn > 1400ng/L (HR,2.34; 95% CI,1.29-4.25; P = 0.005) for shorter BPT. In survival analysis, primary tumor size > 2 cm (HR, 5.81; 95% CI,2.20-15.38; P < 0.01), CNT > 1 month (HR, 5.69; 95% CI, 1.17-27.61; P = 0.031) and multifocality (HR, 3.10; 95% CI, 1.45-6.65; P = 0.004) were independent predictor of DFS. CONCLUSION: Early changes of Ctn after curative surgery can predict the long-term risks of biochemical and structural recurrence, which provide a useful real-time prognostic information. LNR significantly affect the time kinetic of biochemical prognosis. Tumor burden and CNT play a crucial role in MTC survival, the intensity of follow-up must be tailored accordingly.

[Imaging characteristics and diagnosis of primary middle mediastinal tumors].

Objectives: To investigate the proportion of different histological types and CT enhanced imaging features of primary middle mediastinal lesions in order to improve the understanding of these tumors and the accuracy of preoperative diagnosis. Methods: Retrospective analysis was conducted on 84 patients with primary middle mediastinal lesions and clear histological classifications diagnosed and treated at the Cancer Hospital, Chinese Academy of Medical Sciences from January 2012 to December 2022. Clinical, imaging, and pathological data were collected and classified according to tumor histological classifications. CT imaging manifestations such as tumor location, size, morphology, edge, boundary, internal components, enhancement characteristics, and surrounding tissue invasion were evaluated and recorded. Results: The histological types of the primary middle mediastinal lesions from the 84 patients included mesenchymal tumors, anterior intestinal cysts, giant lymph node hyperplasia, substernal goiter, neuroendocrine carcinoma, lymphohematopoietic system tumors, and mesothelioma, accounting for 28.6%, 27.4%, 14.3%, 3.6%, 11.9%, 9.5%, and 4.8%, respectively. Mesenchymal tumors included peripheral nerve sheath tumors, vascular tumors, adipogenic tumors, solitary fibrous tumors, and synovial sarcoma, accounting for 54.2%, 20.8%, 12.5%, 8.3%, and 4.2%, respectively. The above tumors had diverse imaging manifestations and specific imaging features. Mature fat were found in 3 cases of liposarcoma; Calcification was observed in 2 cases of thyroid nodules and 7 cases of giant lymph node hyperplasia; Enhanced scanning showed significant enhancement in 2 cases of solitary fibrous tumors, 3 cases of thyroid nodules, and 11 cases of giant lymph node hyperplasia; Mediastinal large lymph nodes was observed in 6 cases of lymphoma and 3 cases of mesothelioma; High invasiveness was observed in 4 cases of mesothelioma and 9 cases of neuroendocrine carcinoma. Conclusion: Mediastinal tumors have low incidence rate and rich histological types, and their imaging manifestations are diverse. Preoperative differential diagnosis can be made according to their specific imaging characteristics.

CytoLyt fixation impedes insulinoma-associated protein 1 (INSM1) immunoreactivity compared to formalin fixation.

INTRODUCTION: Insulinoma-associated protein 1 (INSM1) is an immunohistochemical marker commonly used to confirm cytomorphological concordant neuroendocrine tumors/carcinomas (NETs/NECs), demonstrating high utility in small samples. Previous reports have suggested comparable INSM1 staining in CytoLyt-fixed cell blocks and formalin-fixed surgical pathology specimens. This study aimed to assess INSM1 immunoreactivity using both fixation methods and investigate potential factors contributing to its variable expression. MATERIALS AND METHODS: A retrospective query was performed (03/31/21-05/31/22) for NET/NEC cases that had both formalin- and CytoLyt-fixed cell blocks. We collected clinical data and reporting of immunostains for each case. INSM1 staining was evaluated in both fixation methods, and reported as positive, negative, or equivocal. Equivocal INSM1 staining was further scored as a percentage of 1%-100% and intensity of weak (faint staining), moderate (darker staining), and strong (dense staining). RESULTS: Our search identified 20 cases from diverse body sites, including mediastinal lymph nodes (40%), pancreas (35%), lung (20%), and porta hepatis lymph nodes (5%). All cases exhibited a widespread positivity (over 90%) in formalin-fixed cell blocks. In contrast, CytoLyt fixed cells showed a negative stain in 65% of cases and 30% exhibited an equivocal positivity. CONCLUSIONS: While INSM1 is previously reported as a sensitive (75%-100%) and specific (82.7%-100%) marker for NET/NECs, our study found a reduced immunohistochemical staining in CytoLyt-fixed cell blocks. Consequently, false negative INSM1 immunohistochemical results in CytoLyt-fixed cell block material may pose a pitfall in the diagnosis of NET/NEC.

An orthotopic prostate cancer model for new treatment development using syngeneic or patient-derived tumors.

BACKGROUND: There are limited preclinical orthotopic prostate cancer models due to the technical complexity of surgical engraftment and tracking the tumor growth in the mouse prostate gland. Orthotopic xenografts recapitulate the tumor microenvironment, tumor stromal interactions, and clinical behavior to a greater extent than xenografts grown at subcutaneous or intramuscular sites. METHODS: This study describes a novel micro-surgical technique for orthotopically implanting intact tumors pieces from cell line derived (transgenic adenocarcinoma mouse prostate [TRAMP]-C2) or patient derived (neuroendocrine prostate cancer [NEPC]) tumors in the mouse prostate gland and monitoring tumor growth using magnetic resonance (MR) imaging. RESULTS: The TRAMP-C2 tumors grew rapidly to a predetermined endpoint size of 10 mm within 3 weeks, whereas the NEPC tumors grew at a slower rate over 7 weeks. The tumors were readily detected by MR and confidently identified when they were approximately 2-3 mm in size. The tumors were less well-defined on CT. The TRAMP-C2 tumors were characterized by amorphous sheets of poorly differentiated cells similar to a high-grade prostatic adenocarcinoma and frequent macroscopic peritoneal and lymph node metastases. In contrast, the NEPC's displayed a neuroendocrine morphology with polygonal cells arranged in nests and solid sheets and high count. There was a local invasion of the bladder and other adjacent tissues but no identifiable metastases. The TRAMP-C2 tumors were more hypoxic than the NEPC tumors. CONCLUSIONS: This novel preclinical orthotopic prostate cancer mouse model is suitable for either syngeneic or patient derived tumors and will be effective in developing and advancing the current selection of treatments for patients with prostate cancer.

Integrated mutational landscape analysis of poorly differentiated high-grade neuroendocrine carcinoma of the uterine cervix.

High-grade neuroendocrine cervical cancers (NETc) are exceedingly rare, highly aggressive tumors. We analyzed 64 NETc tumor samples by whole-exome sequencing (WES). Human papillomavirus DNA was detected in 65.6% (42/64) of the tumors. Recurrent mutations were identified in PIK3CA, KMT2D/MLL2, K-RAS, ARID1A, NOTCH2, and RPL10. The top mutated genes included RB1, ARID1A, PTEN, KMT2D/MLL2, and WDFY3, a gene not yet implicated in NETc. Somatic CNV analysis identified two copy number gains (3q27.1 and 19q13.12) and five copy number losses (1p36.21/5q31.3/6p22.2/9q21.11/11p15.5). Also, gene fusions affecting the ACLY-CRHR1 and PVT1-MYC genes were identified in one of the eight samples subjected to RNA sequencing. To resolve evolutionary history, multiregion WES in NETc admixed with adenocarcinoma cells was performed (i.e., mixed-NETc). Phylogenetic analysis of mixed-NETc demonstrated that adenocarcinoma and neuroendocrine elements derive from a common precursor with mutations typical of adenocarcinomas. Over one-third (22/64) of NETc demonstrated a mutator phenotype of C > T at CpG consistent with deficiencies in MBD4, a member of the base excision repair (BER) pathway. Mutations in the PI3K/AMPK pathways were identified in 49/64 samples. We used two patient-derived-xenografts (PDX) (i.e., NET19 and NET21) to evaluate the activity of pan-HER (afatinib), PIK3CA (copanlisib), and ATR (elimusertib) inhibitors, alone and in combination. PDXs harboring alterations in the ERBB2/PI3K/AKT/mTOR/ATR pathway were sensitive to afatinib, copanlisib, and elimusertib (P < 0.001 vs. controls). However, combinations of copanlisib/afatinib and copanlisib/elimusertib were significantly more effective in controlling NETc tumor growth. These findings define the genetic landscape of NETc and suggest that a large subset of these highly lethal malignancies might benefit from existing targeted therapies.

Efficacy of second-line chemotherapy in patients with pulmonary large cell neuroendocrine carcinoma.

The efficacy of second-line chemotherapy in patients with pulmonary large cell neuroendocrine carcinoma (LCNEC) is unclear. This study aimed to evaluate the efficacy of second-line chemotherapy in patients with pulmonary LCNEC. We retrospectively reviewed patients with pulmonary LCNEC or possible LCNEC (pLCNEC) who received platinum-based chemotherapy as the first-line treatment. Among these patients, we evaluated the efficacy of second-line treatment by comparing patients with small cell lung cancer (SCLC group). Of the 61 patients with LCNEC or pLCNEC (LCNEC group) who received first-line chemotherapy, 39 patients were treated with second-line chemotherapy. Among the 39 patients, 61.5% received amrubicin monotherapy. The median progression-free survival (PFS) and overall survival (OS) in the LCNEC groups were 3.3 and 8.3 months, respectively. No significant differences in the PFS (hazard ratio [HR]: 0.924, 95% confidence interval [CI] 0.647-1.320; P = 0.664) and OS (HR: 0.926; 95% CI 0.648-1.321; P = 0.670) were observed between the LCNEC and SCLC groups. In patients treated with amrubicin, the PFS (P = 0.964) and OS (P = 0.544) were not different between both the groups. Second-line chemotherapy, including amrubicin, may be considered as a treatment option for patients with pulmonary LCNEC.

Automated imaging analysis of Ki-67 immunohistochemistry on whole slide images of cell blocks from pancreatic neuroendocrine neoplasms.

INTRODUCTION: Accurate grading of pancreatic neuroendocrine tumors (PanNETs) relies on the assessment of Ki-67 immunohistochemistry (IHC). While digital imaging analysis (DIA) has been employed for Ki-67 IHC assessment in surgical specimens, its applicability to cytologic specimens remains underexplored. This study aimed to evaluate an automated DIA for assessing Ki-67 IHC on PanNET cell blocks. MATERIALS AND METHODS: The study included 61 consecutive PanNETs and 5 pancreatic neuroendocrine carcinomas. Ki-67 IHC slides from cell blocks were digitally scanned into whole slide images using Philips IntelliSite Scanners and analyzed in batches using the Visiopharm Ki-67 App in a digital workflow. Ki-67 scores obtained through DIA were compared to pathologists' manual scores. RESULTS: The Pearson correlation coefficient of the percentage of Ki-67-stained nuclei between DIA reads and the originally reported reads was 0.9681. Concordance between DIA Ki-67 grades and pathologists' Ki-67 grades was observed in 92.4% (61/66) of cases with the calculated Cohen's Kappa coefficient of 0.862 (almost perfect agreement). Discordance between DIA and pathologists' consensus reads occurred in 5 PanNET cases which were upgraded from G1 to G2 by DIA due to contaminated Ki-67-stained inflammatory cells. CONCLUSIONS: DIA demonstrated excellent concordance with pathologists' assessments, with only minor grading discrepancies. However, the essential role of pathologists in confirming results is emphasized to enhance overall accuracy.

Expression and clinical value of CXCR4 in high grade gastroenteropancreatic neuroendocrine neoplasms.

Background: CXC chemokine receptor 4 (CXCR4) is associated with the progression and metastasis of numerous malignant tumors. However, its relationship with Gastroenteropancreatic Neuroendocrine Neoplasms Grade 3 (GEP-NENs G3) is unclear. The aim of this study was to characterize the expression of CXCR4 in GEP-NENS and to explore the clinical and prognostic value of CXCR4. Methods: This study retrospectively collected clinical and pathological data from patients with GEP-NENs who receiving surgery in Qilu Hospital of Shandong University from January 2013 to April 2021, and obtained the overall survival of the patients based on follow-up. Immunohistochemistry (IHC) was performed on pathological paraffin sections to observe CXCR4 staining. Groups were made according to pathological findings. Kaplan-Meier (K-M) curve was used to evaluate prognosis. SPSS 26.0 was used for statistical analysis. Results: 100 GEP-NENs G3 patients were enrolled in this study. There was a significant difference in primary sites (P=0.002), Ki-67 index (P<0.001), and Carcinoembryonic Antigen (CEA) elevation (P=0.008) between neuroendocrine tumor (NET) G3 and neuroendocrine carcinoma (NEC). CXCR4 was highly expressed only in tumors, low or no expressed in adjacent tissues (P<0.001). The expression level of CXCR4 in NEC was significantly higher than that in NET G3 (P=0.038). The K-M curves showed that there was no significant difference in overall survival between patients with high CXCR4 expression and patients with low CXCR4 expression, either in GEP-NEN G3 or NEC (P=0.920, P=0.842. respectively). Conclusion: Differential expression of CXCR4 was found between tumor and adjacent tissues and between NET G3 and NEC. Our results demonstrated that CXCR4 can be served as a new IHC diagnostic indicator in the diagnosis and differential diagnosis of GEP-NENs G3. Further studies with multi-center, large sample size and longer follow-up are needed to confirm the correlation between CXCR4 expression level and prognosis.

Initial surgical management of sporadic medullary thyroid cancer: Guidelines based optimal care - A systematic review.

INTRODUCTION: Medullary thyroid carcinoma (MTC) is a rare neuroendocrine tumor from parafollicular cells that produce calcitonin (Ct). Despite several existing guidelines for the surgical management of sporadic MTC (sMTC), optimal initial surgical management of the thyroid, the central and the lateral neck remains a matter of debate. METHODS: A systematic review in PubMed and Scopus for current guidelines addressing the surgical management of sMTC and its referenced citations was conducted as per the PRISMA guidelines. RESULTS: Two-hundred and one articles were identified, of which 7 met the inclusion criteria. Overall, guidelines vary significantly in their recommendations for the surgical management of sMTC. Only one guideline recommended partial thyroidectomy for limited disease, but the possibility to avoid completion thyroidectomy in selected cases is acknowledged in 42% (3/7) of the remaining guidelines. The majority of guidelines (71.4%; 5/7) recommended prophylactic central neck dissection (CND) for all patients while the remaining two guidelines recommended CND based on Ct level and tumor size. The role of prophylactic lateral neck dissection based on preoperative Ct levels was recommended by 42% (3/7) of guidelines. Overall, these guidelines are based on low-quality evidence, mostly single-center retrospective series, some of which are over 20 years old. CONCLUSION: Current surgical management guidelines of sMTC should be revised, and ought to be based on updated data challenging current recommendations, which are based on historic, low-quality evidence. Partial thyroidectomy may become a viable option for small, limited tumors. Prospective, multi-center studies may be useful to conclude whether prophylactic ND is necessary in all sMTC patients.

Updates on Urinary Bladder Tumors With Neuroendocrine Features.

The most common neuroendocrine tumor in the urinary bladder is small cell carcinoma, which can be pure or mixed with components of urothelial or other histologic subtypes. Large cell neuroendocrine carcinoma of the bladder is rare and remains ill-defined but is increasingly recognized. Well-differentiated neuroendocrine tumor and paraganglioma can arise in the bladder but are very rare in this location. Recent advances in molecular characterization allowed for better classification and may offer improved stratification of these tumors.

Paget Disease of Bone Harboring Bone Metastatic Neuroendocrine Cancer: A Case Report.

In this case report, we describe an uncommon case of neuroendocrine cancer of unknown origin began with cauda equina syndrome in a patient affected by Paget disease of bone (PDB). A 76-year-old man with diagnosis of PDB, without history of pain or bone deformity, developed sudden severe low back pain. Bone alkaline phosphatase was increased and MRI and whole-body scintigraphy confirmed the localization of the disease at the third vertebra of the lumbar spine. Treatment with Neridronic Acid was started, but after only 2 weeks of therapy anuria and bowel occlusion occurred together with lower limb weakness and walking impairment. Cauda equina syndrome consequent to spinal stenosis at the level of L2-L3 was diagnosed after admission to Emergency Department and the patient underwent neurosurgery for spinal medulla decompression. The histologic results showed a complete subversion of bone structure in neoplastic tissue, consistent with metastatic neuroendocrine carcinoma of unknown origin. In conclusion, low back pain in the elderly may require deep investigation to individuate rare diseases. In asymptomatic patients with apparently stable PDB, the sudden appearance of pain or neurologic symptoms may alert the clinician for the possibility of other superimposing diseases, like bone metastases.

Treatment Outcomes of Second-Line Systemic Therapy for Neuroendocrine Prostate Cancer: A Report of Four Cases.

Neuroendocrine prostate cancer (NEPC) is a histological variant of prostate cancer and is characterized by aggressiveness and poor clinical outcomes. NEPC usually develops as a mechanism of treatment resistance in patients receiving hormone therapy for advanced prostate cancer. NEPC is sensitive to primary platinum-based chemotherapy, and has a short response duration. Second-line therapy is required in many cases, but clinical data on subsequent treatment after progression to first-line chemotherapy is limited. Here we report our experience of four cases of NEPC treated with second-line chemotherapy. Progression-free and overall survival rates were very low in three of the patients. One patient received multidisciplinary therapy using systemic and local chemotherapy and radiation therapy and survived for 24 months after initiation of second-line chemotherapy. Multidisciplinary therapy with chemotherapy and radiation is a promising option for improving the survival of patients with NEPC.

Patient-derived tumoroid models of pulmonary large-cell neuroendocrine carcinoma: a promising tool for personalized medicine and developing novel therapeutic strategies.

Pulmonary large-cell neuroendocrine carcinoma (LCNEC), a disease with poor prognosis, is classified as pulmonary high-grade neuroendocrine carcinoma, along with small-cell lung cancer. However, given its infrequent occurrence, only a limited number of preclinical models have been established. Here, we established three LCNEC tumoroids for long-term culture. Whole-exome sequencing revealed that these tumoroids inherited genetic mutations from their parental tumors; two were classified as small-cell carcinoma (S-LCNEC) and one as non-small cell carcinoma (N-LCNEC). Xenografts from these tumoroids in immunodeficient mice mimicked the pathology of the parent LCNEC, and one reproduced the mixed-tissue types of combined LCNEC with a component of adenocarcinoma. Drug sensitivity tests using these LCNEC tumoroids enabled the evaluation of therapeutic agent efficacy. Based on translational research, we found that a CDK4/6 inhibitor might be effective for N-LCNEC and that Aurora A kinase inhibitors might be suitable for S-LCNEC or LCNEC with MYC amplification. These results highlight the value of preclinical tumoroid models in understanding the pathogenesis of rare cancers and developing treatments. LCNEC showed a high success rate in tumoroid establishment, indicating its potential application in personalized medicine.

Neuroendocrine and squamous cell phenotypes of NUT carcinoma are potential diagnostic pitfalls that discriminating it from mimickers, such as small cell and squamous cell carcinoma.

INTRODUCTION: NUT carcinoma is a rare cancer associated with a poor prognosis. Because of its rarity, its diagnosis is challenging and is usually made by excluding other diagnoses. Immunohistochemical analysis is a reliable technique that contributes to a correct diagnosis, but overestimating the expression of neuroendocrine (NE) markers may result in an incorrect diagnosis. In this study, we established the immunohistochemical phenotypes of NUT carcinoma compared with tumors that mimic its phenotype to identify potential diagnostic pitfalls. METHODS: Eight cases of NUT carcinoma were examined along with eight basaloid squamous cell carcinomas and thirteen cases of small cell carcinoma using an immunohistochemical panel consisting of various antibodies. RESULTS: Of the eight NUT carcinomas, three patients had a smoking history. All the cases examined for INSM1 were positive (6/6, 100%), although the staining was somewhat weak. Among the NE markers, synaptophysin was variably positive in two NUT carcinomas (2/6, 33%); however, all cases were negative for ASCL1, chromogranin A, and CD56. Moreover, the squamous cell markers, p40 and CK5/6, were weakly expressed in 4/6 (67%) and 3/6 (50%) of the NUT carcinomas, respectively. CONCLUSIONS: For tumors with an ambiguous morphology, applying the neuroendocrine phenotype of NUT carcinoma may be misleading; particularly, when distinguishing it from small-cell carcinoma. Similarly, null or weak expression of squamous cell markers may be observed in NUT carcinoma, but this differs from squamous cell carcinoma, which consistently demonstrates strong positivity for squamous cell markers.

PITX2 as a Sensitive and Specific Marker of Midgut Neuroendocrine Tumors: Results from a Cohort of 1157 Primary Neuroendocrine Neoplasms.

As neuroendocrine tumors (NETs) often present as metastatic lesions, immunohistochemical assignment to a site of origin is one of the most important tasks in their pathologic assessment. Because a fraction of NETs eludes the typical expression profiles of their primary localization, additional sensitive and specific markers are required to improve diagnostic certainty. We investigated the expression of the transcription factor Pituitary Homeobox 2 (PITX2) in a large-scale cohort of 909 NET and 248 neuroendocrine carcinomas (NEC) according to the immunoreactive score (IRS) and correlated PITX2 expression groups with general tumor groups and primary localization. PITX2 expression (all expression groups) was highly sensitive (98.1%) for midgut-derived NET, but not perfectly specific, as non-midgut NET (especially pulmonary/duodenal) were quite frequently weak or moderately positive. The specificity rose to 99.5% for a midgut origin of NET if only a strong PITX2 expression was considered, which was found in only 0.5% (one pancreatic/one pulmonary) of non-midgut NET. In metastases of midgut-derived NET, PITX2 was expressed in all cases (87.5% strong, 12.5% moderate), whereas CDX2 was negative or only weakly expressed in 31.3% of the metastases. In NEC, a fraction of cases (14%) showed a weak or moderate PITX2 expression, which was not associated with a specific tumor localization. Our study independently validates PITX2 as a very sensitive and specific immunohistochemical marker of midgut-derived NET in a very large collective of neuroendocrine neoplasms. Therefore, our data argue toward implementation into diagnostic panels applied for NET as a firstline midgut marker.

Hand2 Immunohistochemistry in the Diagnosis of Paragangliomas and Other Neuroendocrine Neoplasms.

Hand2 is a core transcription factor responsible for chromaffin cell differentiation. However, its potential utility in surgical pathology has not been studied. Thus, we aimed to investigate its expression in paragangliomas, other neuroendocrine neoplasms (NENs), and additional non-neuroendocrine tumors. We calibrated Hand2 immunohistochemistry on adrenal medulla cells and analyzed H-scores in 46 paragangliomas (PGs), 9 metastatic PGs, 21 cauda equina neuroendocrine tumors (CENETs), 48 neuroendocrine carcinomas (NECs), 8 olfactory neuroblastomas (ONBs), 110 well-differentiated NETs (WDNETs), 10 adrenal cortical carcinomas, 29 adrenal cortical adenomas, 8 melanomas, 41 different carcinomas, and 10 gastrointestinal stromal tumors (GISTs). Both tissue microarrays (TMAs) and whole sections (WSs) were studied. In 171 NENs, previously published data on Phox2B and GATA3 were correlated with Hand2. Hand2 was positive in 98.1% (54/55) PGs, but only rarely in WDNETs (9.6%, 10/104), CENETs (9.5%, 2/21), NECs (4.2%, 2/48), or ONBs (12.5%, 1/8). Any Hand2 positivity was 98.1% sensitive and 91.7% specific for the diagnosis of PG. The Hand2 H-score was significantly higher in primary PGs compared to Hand2-positive WDNETs (median 166.3 vs. 7.5; p < 0.0001). Metastatic PGs were positive in 88.9% (8/9). No Hand2 positivity was observed in any adrenal cortical neoplasm or other non-neuroendocrine tumors, with exception of 8/10 GISTs. Parasympathetic PGs showed a higher Hand2 H-score compared to sympathetic PGs (median H-scores 280 vs. 104, p < 0.0001). Hand2 positivity in NENs serves as a reliable marker of primary and metastatic PG, since other NENs only rarely exhibit limited Hand2 positivity.

Primary Oral Mixed Neuroendocrine-Non-neuroendocrine Neoplasm (MiNEN): A Rare Case Report and Review of the Literature.

Mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) are rare tumors recently characterized by the presence of both neuroendocrine and non-neuroendocrine components within the same tumor tissue. Although MiNEN found their place in the WHO classification for various organs, this composite tumor in the head and neck region remains exceptionally rare. We present a case of primary oral MiNEN in a 64-year-old male located on the left side of lower gingiva. Biopsy raised suspicion of neuroendocrine carcinoma (NEC) and the patient underwent partial mandibulectomy. The resected specimen showed two distinct components of NEC and squamous cell carcinoma (SCC) with the confirmation of immunohistochemical markers. There has been no sign of recurrence nor metastasis 6 years after the surgery. In addition, we have conducted a review of published cases with potential relevance to this entity, resulting in five cases. The diverse terminology reinforces the need for a standardized classification system of oral/head and neck MiNENs.