Cytological Features of Fibrin-associated Diffuse Large B-cell Lymphoma Arising in Retroperitoneal Pseudocyst: The First Case Report.

BACKGROUND/AIM: Fibrin-associated diffuse large B-cell lymphoma (FA-DLBCL) is frequently associated with the Epstein-Barr virus (EBV) and manifests as non-mass-forming microscopic lesions within fibrin-rich lesions. Herein, we describe the cytological features of FA-DLBCL. CASE REPORT: A 72-year-old man presented with a large retroperitoneal cystic mass that was treated by cyst aspiration and laparoscopic excision. Individually dispersed large, atypical cells in a necrotic background contained scant cytoplasm and hyperchromatic nuclei with irregular nuclear contours, frequent karyorrhectic debris, and mitotic figures. A fibrinous exudate with necrotic material attached to the inner surface of the cystic mass contained large, atypical cells that were individually scattered or arranged in small clusters. These were positive for cluster of differentiation 20 and Epstein-Barr virus-encoded RNA in situ hybridization. CONCLUSION: We cytologically characterized FA-DLBCL as large, atypical cells that were individually scattered or arranged in small clusters in a necrotic background. To the best of our knowledge, we revealed the cytological features of FA-DLBCL.

A 42-year-old patient with renal cell carcinoma presenting as low back pain: A case report.

RATIONALE: Renal cell carcinoma (RCC) is the most common renal neoplasm, accounting for 2.4% of all cancers in Korea. Although the usual clinical manifestations of RCC include flank pain, hematuria, and palpable mass, RCC is generally characterized by a lack of early warning signs and is mostly discovered incidentally in advanced stage. This case report describes a 42-year-old Korean man diagnosed with giant RCC who presented with simple back pain. PATIENT CONCERNS: The clinical manifestation of a 42-year-old Korean man was chronic back pain. DIAGNOSES: Contrast-enhanced computed tomography showed a 19.1-cm sized heterogeneous enhancing mass on the right kidney and tumor thrombosis extending into inferior vena cava. INTERVENTION: Due to the large size of the tumor and extensive tumor thrombosis, the multidisciplinary team decided to administer neoadjuvant chemotherapy and an anticoagulant. Following 12 cycles of treatment with nivolumab and cabozantinib, he underwent a right radical nephrectomy with an adrenalectomy and tumor thrombectomy. OUTCOMES: Treatment was successful and posttreatment he started a cancer rehabilitation program. He was followed-up as an outpatient and no longer complains of back pain. LESSONS: RCC can manifest clinically as back pain, with diagnosis being difficult without appropriate imaging modalities. RCC should be included in the differential diagnosis of patients with low back pain, even at a young age.

Augmented interpretation of HER2, ER, and PR in breast cancer by artificial intelligence analyzer: enhancing interobserver agreement through a reader study of 201 cases.

BACKGROUND: Accurate classification of breast cancer molecular subtypes is crucial in determining treatment strategies and predicting clinical outcomes. This classification largely depends on the assessment of human epidermal growth factor receptor 2 (HER2), estrogen receptor (ER), and progesterone receptor (PR) status. However, variability in interpretation among pathologists pose challenges to the accuracy of this classification. This study evaluates the role of artificial intelligence (AI) in enhancing the consistency of these evaluations. METHODS: AI-powered HER2 and ER/PR analyzers, consisting of cell and tissue models, were developed using 1,259 HER2, 744 ER, and 466 PR-stained immunohistochemistry (IHC) whole-slide images of breast cancer. External validation cohort comprising HER2, ER, and PR IHCs of 201 breast cancer cases were analyzed with these AI-powered analyzers. Three board-certified pathologists independently assessed these cases without AI annotation. Then, cases with differing interpretations between pathologists and the AI analyzer were revisited with AI assistance, focusing on evaluating the influence of AI assistance on the concordance among pathologists during the revised evaluation compared to the initial assessment. RESULTS: Reevaluation was required in 61 (30.3%), 42 (20.9%), and 80 (39.8%) of HER2, in 15 (7.5%), 17 (8.5%), and 11 (5.5%) of ER, and in 26 (12.9%), 24 (11.9%), and 28 (13.9%) of PR evaluations by the pathologists, respectively. Compared to initial interpretations, the assistance of AI led to a notable increase in the agreement among three pathologists on the status of HER2 (from 49.3 to 74.1%, p < 0.001), ER (from 93.0 to 96.5%, p = 0.096), and PR (from 84.6 to 91.5%, p = 0.006). This improvement was especially evident in cases of HER2 2+ and 1+, where the concordance significantly increased from 46.2 to 68.4% and from 26.5 to 70.7%, respectively. Consequently, a refinement in the classification of breast cancer molecular subtypes (from 58.2 to 78.6%, p < 0.001) was achieved with AI assistance. CONCLUSIONS: This study underscores the significant role of AI analyzers in improving pathologists' concordance in the classification of breast cancer molecular subtypes.

Coexistence of Colorectal Cancer and Immunoglobulin G4-Related Disease in the Same Lesion: A Rare Case with Molecular Classification.

Immunoglobulin G4-related disease (IgG4-RD) is a novel fibroinflammatory disorder characterized by enlargement of the involved organs, elevated IgG4 levels, and abundant infiltration of IgG4-positive plasma cells. Indeed, primary colon cancers arising from IgG4-RD are rare. This case report describes a rare occurrence of simultaneous colorectal cancer and IgG4-RD in the same lesion in a 62-year-old male patient. The patient underwent a right hemicolectomy under the suspicion of primary colon cancer. The mass was grossly well-defined and yellowish tan, and the background colon was fibrotic. Microscopically, the tumor cells showed glandular differentiation characteristic of adenocarcinoma in a background of dense lymphoplasmacytic infiltration with fibrosis and obliterative phlebitis in the pericolic fat tissue. IgG4 immunohistochemical staining showed diffuse positivity in infiltrating plasma cells. The patient was administered adjuvant chemotherapy and prednisolone therapy. The patient's serum IgG4 levels gradually decreased, and a follow-up positron emission tomography-computed tomography scan 1 year after surgery showed no evidence of local or distant recurrence of colorectal cancer. IgG4-RD occurring concurrently with primary colon adenocarcinoma has not been reported. Increased awareness of this rare coexistence can guide clinicians in navigating diagnostic complexities and selecting optimal therapeutic strategies.

Proximal dendritic localization of NALCN channels underlies tonic and burst firing in nigral dopaminergic neurons.

In multipolar nigral dopamine (DA) neurons, the highly excitable proximal dendritic compartments (PDCs) and two Na+ -permeable leak channels, TRPC3 and NALCN, play a key role in pacemaking. However, the causal link between them is unknown. Here we report that the proximal dendritic localization of NALCN underlies pacemaking and burst firing in DA neurons. Our morphological analysis of nigral DA neurons reveals that TRPC3 is ubiquitously expressed in the whole somatodendritic compartment, but NALCN is localized within the PDCs. Blocking either TRPC3 or NALCN channels abolished pacemaking. However, only blocking NALCN, not TRPC3, degraded burst discharges. Furthermore, local glutamate uncaging readily induced burst discharges within the PDCs, compared with other parts of the neuron, and NALCN channel inhibition dissipated burst generation, indicating the importance of NALCN to the high excitability of PDCs. Therefore, we conclude that PDCs serve as a common base for tonic and burst firing in nigral DA neurons. KEY POINTS: Midbrain dopamine (DA) neurons are slow pacemakers that can generate tonic and burst firings, and the highly excitable proximal dendritic compartments (PDCs) and two Na+ -permeable leak channels, TRPC3 and NALCN, play a key role in pacemaking. We find that slow tonic firing depends on the basal activity of both the NALCN and TRPC3 channels, but that burst firing does not require TRPC3 channels but relies only on NALCN channels. We find that TRPC3 is ubiquitously expressed in the entire somatodendritic compartment, but that NALCN exists only within the PDCs in nigral DA neurons. We show that NALCN channel localization confers high excitability on PDCs and is essential for burst generation in nigral DA neurons. These results suggest that PDCs serve as a common base for tonic and burst firing in nigral DA neurons.

Pneumocystis Pneumonia in a Non-Immunocompromised Lung Cancer Patient after Surgery: A Case Report.

We present the Pneumocystis pneumonia case of a 64-year-old man with no remarkable history except for hypertension, who had not undergone any treatment other than surgery. On postoperative day 7, high-resolution computed tomography findings revealed multifocal ground-glass opacifications with interlobular septal thickening in both lungs; therefore, atypical pneumonia was suspected. Polymerase chain reaction (PCR) test performed after bronchoalveolar lavage was positive for Pneumocystis jirovecii (P. jirovecii). Based on the PCR results, a final diagnosis of Pneumocystis pneumonia (PCP) was made. After treatment, he improved and was discharged. This is a unique case of PCP diagnosis in a non-immunocompromised patient, with no remarkable history except for hypertension, who had not undergone any treatment other than surgery for cancer. Thus, it is necessary to consider additional risk factors for PCP and timing of preventive treatment.

The intracellular Ca2+ channel TRPML3 is a PI3P effector that regulates autophagosome biogenesis.

Autophagy is a multiple fusion event, initiating with autophagosome formation and culminating with fusion with endo-lysosomes in a Ca2+-dependent manner. The source of Ca2+ and the molecular mechanism by which Ca2+ is provided for this process are not known. The intracellular Ca2+ permeable channel transient receptor potential mucolipin 3 (TRPML3) localizes in the autophagosome and interacts with the mammalian autophagy-related protein 8 (ATG8) homolog GATE16. Here, we show that lipid-regulated TRPML3 is the Ca2+ release channel in the phagophore that provides the Ca2+ necessary for autophagy progress. We generated a TRPML3-GCaMP6 fusion protein as a targeted reporter of TRPML3 compartment localization and channel function. Notably, TRPML3-GCaMP6 localized in the phagophores, the level of which increased in response to nutrient starvation. Importantly, phosphatidylinositol-3-phosphate (PI3P), an essential lipid for autophagosome formation, is a selective regulator of TRPML3. TRPML3 interacted with PI3P, which is a direct activator of TRPML3 current and Ca2+ release from the phagophore, to promote and increase autophagy. Inhibition of TRPML3 suppressed autophagy even in the presence of excess PI3P, while activation of TRPML3 reversed the autophagy inhibition caused by blocking PI3P. Moreover, disruption of the TRPML3-PI3P interaction abolished both TRPML3 activation by PI3P and the increase in autophagy. Taken together, these results reveal that TRPML3 is a downstream effector of PI3P and a key regulator of autophagy. Activation of TRPML3 by PI3P is the critical step providing Ca2+ from the phagophore for the fusion process, which is essential for autophagosome biogenesis.

MicroRNA-dependent inhibition of WEE1 controls cancer stem-like characteristics and malignant behavior in ovarian cancer.

Cancer stem-like cells (CSCs) have been suggested to be responsible for chemoresistance and tumor recurrence owing to their self-renewal capacity and differentiation potential. Although WEE1 is a strong candidate target for anticancer therapies, its role in ovarian CSCs is yet to be elucidated. Here, we show that WEE1 plays a key role in regulating CSC properties and tumor resistance to carboplatin via a microRNA-dependent mechanism. We found that WEE1 expression is upregulated in ovarian cancer spheroids because of the decreased expression of miR-424 and miR-503, which directly target WEE1. The overexpression of miR-424/503 suppressed CSC activity by inhibiting WEE1 expression, but this effect was reversed on the restoration of WEE1 expression. Furthermore, we demonstrated that NANOG modulates the miR-424/503-WEE1 axis that regulates the properties of CSCs. We also demonstrated the pharmacological restoration of the NANOG-miR-424/503-WEE1 axis and attenuation of ovarian CSC characteristics in response to atorvastatin treatment. Lastly, miR-424/503-mediated WEE1 inhibition re-sensitized chemoresistant ovarian cancer cells to carboplatin. Additionally, combined treatment with atorvastatin and carboplatin synergistically reduced tumor growth, chemoresistance, and peritoneal seeding in the intraperitoneal mouse models of ovarian cancer. We identified a novel NANOG-miR-424/503-WEE1 pathway for regulating ovarian CSCs, which has potential therapeutic utility in ovarian cancer treatment.

Synaptophysin, CD117, and GATA3 as a Diagnostic Immunohistochemical Panel for Small Cell Neuroendocrine Carcinoma of the Urinary Tract.

Although SCNEC is based on its characteristic histology, immunohistochemistry (IHC) is commonly employed to confirm neuroendocrine differentiation (NED). The challenge here is that SCNEC may yield negative results for traditional neuroendocrine markers. To establish an IHC panel for NED, 17 neuronal, basal, and luminal markers were examined on a tissue microarray construct generated from 47 cases of 34 patients with SCNEC as a discovery cohort. A decision tree algorithm was employed to analyze the extent and intensity of immunoreactivity and to develop a diagnostic model. An external cohort of eight cases and transmission electron microscopy (TEM) were used to validate the model. Among the 17 markers, the decision tree diagnostic model selected 3 markers to classify NED with 98.4% accuracy in classification. The extent of synaptophysin (>5%) was selected as the initial parameter, the extent of CD117 (>20%) as the second, and then the intensity of GATA3 (≤1.5, negative or weak immunoreactivity) as the third for NED. The importance of each variable was 0.758, 0.213, and 0.029, respectively. The model was validated by the TEM and using the external cohort. The decision tree model using synaptophysin, CD117, and GATA3 may help confirm NED of traditional marker-negative SCNEC.

Combination of GATA3, SOX-10, and PAX8 in a Comprehensive Panel to Diagnose Breast Cancer Metastases.

BACKGROUND/AIM: It can be difficult to establish the origin of a tumor in metastatic breast cancer (MBC), especially with triple-negative breast cancer (TNBC) or high-grade features. We evaluated the diagnostic utility of GATA3, SOX10, and PAX8 panels in MBC by comparing their expression in each molecular subtype of MBC. PATIENTS AND METHODS: We evaluated 84 MBC and 37 primary TNBC cases using GATA3, SOX10, and PAX8 staining in whole tissue sections. RESULTS: GATA3 was least sensitive in the detection of metastatic TNBC (metastatic non-TNBC, 0.95; metastatic TNBC, 0.37). SOX10 had the lowest overall sensitivity (0.12) but was elevated in metastatic TNBC, even higher than GATA3 (0.59 vs. 0.37). The combination of GATA3, SOX10, and PAX8 expression showed the highest detection rate (MBC, 0.94; metastatic non-TNBC, 0.95; metastatic TNBC, 0.93). CONCLUSION: We recommend combining GATA3, SOX10, PAX8 expression profiling to confirm breast as the site of origin in metastatic MBC.

Unusual cause of gastric outlet obstruction mimicking superior mesenteric artery syndrome: A case of infiltrative duodenal cancer arising from a choledochocele.

Choledochocele is a rare subtype of choledochal cyst and is associated with increased prevalence of periampullary cancers. Here, we report an unusual manifestation of infiltrative duodenal cancer arising from a choledochocele, involving superficial spreading (muscularis mucosae) of cancer cells along the duodenum causing gastric outlet obstruction, which clinically mimicked superior mesenteric artery syndrome. Histologically, wide spread of cancer cells was confirmed from periampullary region to duodenojejunal junction showing mismatch with radiologic findings, in which the cancer segment was mainly located in the distal duodenum. Clinical, radiologic, and pathologic findings are discussed with literature reviews.

Radiomic models based on magnetic resonance imaging predict the spatial distribution of CD8+ tumor-infiltrating lymphocytes in breast cancer.

Infiltration of CD8+ T cells and their spatial contexture, represented by immunophenotype, predict the prognosis and therapeutic response in breast cancer. However, a non-surgical method using radiomics to evaluate breast cancer immunophenotype has not been explored. Here, we assessed the CD8+ T cell-based immunophenotype in patients with breast cancer undergoing upfront surgery (n = 182). We extracted radiomic features from the four phases of dynamic contrast-enhanced magnetic resonance imaging, and randomly divided the patients into training (n = 137) and validation (n = 45) cohorts. For predicting the immunophenotypes, radiomic models (RMs) that combined the four phases demonstrated superior performance to those derived from a single phase. For discriminating the inflamed tumor from the non-inflamed tumor, the feature-based combination model from the whole tumor (RM-wholeFC) showed high performance in both training (area under the receiver operating characteristic curve [AUC] = 0.973) and validation cohorts (AUC = 0.985). Similarly, the feature-based combination model from the peripheral tumor (RM-periFC) discriminated between immune-desert and excluded tumors with high performance in both training (AUC = 0.993) and validation cohorts (AUC = 0.984). Both RM-wholeFC and RM-periFC demonstrated good to excellent performance for every molecular subtype. Furthermore, in patients who underwent neoadjuvant chemotherapy (n = 64), pre-treatment images showed that tumors exhibiting complete response to neoadjuvant chemotherapy had significantly higher scores from RM-wholeFC and lower scores from RM-periFC. Our RMs predicted the immunophenotype of breast cancer based on the spatial distribution of CD8+ T cells with high accuracy. This approach can be used to stratify patients non-invasively based on the status of the tumor-immune microenvironment.

Ovarian mass combined with pancreatic neoplasm in pregnancy: A rare case report and literature review.

A 35-year-old woman presented with abdominal discomfort at 26 weeks gestation. The magnetic resonance imaging demonstrated a huge unilocular cystic mass with mural nodules originated from body and tail of pancreas. There was also a cystic mass in the left ovary with suppressed intensity on fat saturated image. One week later, she complained of worsening left lower abdominal pain and dyspnea as a new symptom. Hence, distal pancreatectomy with splenectomy and left ovarian cystectomy were performed. The huge cystic mass of pancreas was compressing the diaphragm, and left tubo-ovarian torsion was observed. This is the second case wherein an MCN of the pancreas with mature cystic teratoma of the ovary caused different symptoms. The management of MCNs in pregnant women should consider multiple aspects such as the malignancy potential of imaging findings, severity of symptoms, and fetal well-being.

Idiopathic Myointimal Hyperplasia of the Mesenteric Veins Is a Peculiar Venous Ischemia That May Be Diagnosed Before Surgery.

BACKGROUND: Idiopathic myointimal hyperplasia of the mesenteric veins is a segmental ischemia associated with noninflammatory hyperplasia of the intimal smooth muscle of the mesenteric veins. Owing to its rarity, timely diagnosis is often difficult. OBJECTIVE: The goal of this study was to improve clinical practice in terms of the diagnosis of idiopathic myointimal hyperplasia of the mesenteric veins. DESIGN: This was a retrospective observational study. SETTINGS: This study was conducted in a single institution with case collection from clinical archives. PATIENTS: Data from 12 cases of idiopathic myointimal hyperplasia of the mesenteric veins were retrieved from 2006-2020. Most patients were elderly men, with a male-to-female ratio of 10:1. MAIN OUTCOME MEASURES: Clinical, endoscopic, radiologic, and pathologic characteristics of idiopathic myointimal hyperplasia of the mesenteric veins served as outcome measures. RESULTS: Radiologically, marked segmental mural thickening and poor enhancement involved the sigmoid colon and rectum in most cases, with extension to the descending colon in some cases. Typical cases showed obliteration of the inferior mesenteric veins and collateral vessels. Colonoscopic findings were reminiscent of ischemia or ulcerative colitis, but sharp demarcation from the uninvolved segment was the most distinguishing feature. Surgically resected specimens showed marked segmental mural thickening, edema, and mucosal discoloration grossly. Microscopically, thick-walled, tortuous veins were observed mainly in the submucosa and subserosa, and the submucosa was markedly thickened in all cases. The subserosal large veins showed myointimal hyperplasia, and pericolic fat necrosis was invariably observed. The most useful histologic finding in biopsy material was tortuous, arteriolized mucosal capillaries with occasional fibrinoid necrosis. LIMITATIONS: This study was limited by its small number of cases and selection bias; there was also no prospective external validation. CONCLUSIONS: Radiologic and pathologic features of idiopathic myointimal hyperplasia of the mesenteric veins are distinct from those of ulcerative colitis or nonspecific ischemic colitis. Careful interpretation of endoscopic and radiologic images and generous biopsies with interpretation by experienced pathologists might lead to an early diagnosis and prevent unnecessary medical treatment. See Video Abstract at http://links.lww.com/DCR/B806. LA HIPERPLASIA MIOINTIMAL IDIOPTICA DE LAS VENAS MESENTRICAS ES UNA PECULIAR ISQUEMIA VENOSA QUE PUEDE DIAGNOSTICARSE ANTES DE LA CIRUGA: ANTECEDENTES:La hiperplasia miointimal idiopática de las venas mesentéricas es una isquemia segmentaria asociada con hiperplasia no inflamatoria del músculo liso de la íntima de las venas mesentéricas. Debido a su rareza, el diagnóstico oportuno suele ser difícil.OBJETIVO:Mejorar la práctica clínica con respecto al diagnóstico de hiperplasia miointimal idiopática de venas mesentéricas.DISEÑO:Estudio observacional retrospectivo.AJUSTES:Institución única, colección de casos de archivos clínicos.PACIENTES:Se recuperaron datos de 12 casos de hiperplasia miointimal idiopática de las venas mesentéricas durante el período 2006-2020. La mayoría de los pacientes eran hombres de edad avanzada, con una proporción de hombres a mujeres de 10:1.PRINCIPALES MEDIDAS DE RESULTADO:Características clínicas, endoscópicas, radiológicas y patológicas de la hiperplasia miointimal idiopática de las venas mesentéricas.RESULTADOS:Radiológicamente, se vio marcado engrosamiento mural afectando de manera segmentaria y escaso realce que comprometieron al colon sigmoides y al recto en la mayoría de los casos, con extensión al colon descendente en algunos casos. Los casos típicos mostraron obliteración de las venas mesentéricas inferiores y vasos colaterales. Los hallazgos colonoscópicos recordaban a la isquemia o la colitis ulcerosa, pero la demarcación nítida del segmento no afectado fue la característica más distintiva. Las piezas quirúrgicas mostraron un marcado engrosamiento mural de manera segmentaria, edema y decoloración de la mucosa de forma macroscópica. Microscópicamente, se observaron venas tortuosas de paredes engrosadas principalmente en la submucosa y subserosa y la submucosa se encontraba marcadamente engrosada en todos los casos. Las grandes venas subserosas mostraban hiperplasia de la mioíntima e invariablemente se observaba necrosis grasa pericólica. El hallazgo histológico más útil en el material de biopsia fueron los tortuosos capilares arteriolizados de la mucosa con necrosis fibrinoide ocasional.LIMITACIONES:Pequeño número de casos; sesgo de selección; sin validación externa prospectiva.CONCLUSIONES:Las características radiológicas y patológicas de la hiperplasia miointimal idiopática de las venas mesentéricas son distintas a las de la colitis ulcerosa o la colitis isquémica no específica. La interpretación cuidadosa de las imágenes endoscópicas y radiológicas y múltiples biopsias de manera generosa con la interpretación de patólogos experimentados pueden conducir a un diagnóstico temprano y prevenir tratamientos médicos innecesarios. Consulte Video Resumen en http://links.lww.com/DCR/B806. (Traducción-Dr Osvaldo Gauto).

Tracheitis Caused by Coinfection with Cytomegalovirus and Herpes Simplex Virus.

Clinically significant isolated viral tracheitis is scarce in adults, and upper airway obstruction caused by viral tracheitis is even more infrequent. A 74-year-old woman, who was administered low-dose steroids for two months for chronic obstructive pulmonary disease (COPD), developed dyspnea with stridor and required mechanical ventilation for respiratory failure. Chest computed tomography showed a diffuse tracheal wall thickening with luminal narrowing and peribronchial consolidation in the right upper lobe. Bronchoscopy revealed a proximal tracheal narrowing with multiple ulcerations of the tracheal mucosa surrounded by an erythematous margin. Pathologic examinations of the tracheal mucosal tissue, including immunohistochemistry, revealed a cytomegalovirus (CMV) and herpes simplex virus (HSV) infection. Furthermore, the bronchial alveolar lavage fluid was positive on the CMV real-time polymerase chain reaction. The patient was treated with intravenous ganciclovir for 44 days. The follow-up bronchoscopy 49 days after the initiation of ganciclovir revealed improved multiple ulcerations with scars. We report a rare case of tracheitis caused by coinfection with CMV and HSV in a patient with COPD who had been taking low-dose steroids for months. The case showed that CMV and HSV are potential causes of serious tracheitis and respiratory failure.

Carcinoma with Triphasic Differentiation Arising from Inverted Papilloma in Sinonasal Sinus: A Rare Case with Molecular Characterization.

Small cell neuroendocrine carcinoma (SNEC) is a rare subset of tumors in the sinonasal sinus. Combined tumors are exceedingly rare. Here, we describe a 65-year-old male with a mixed tumor of SNEC and sarcomatoid carcinoma arising in an inverted papilloma, containing squamous cell carcinoma in situ (SqCCis) in the sinonasal sinus. We evaluated the molecular characteristics of the two separate carcinoma components using next-generation sequencing. The patient presented with a nasal obstruction. Computed tomography showed a mass infiltrating the right ethmoid and maxillary sinuses. An excisional biopsy was performed. The tumor was found to have three morphologically distinct components. The first was SqCCis arising in an inverted papilloma, which was positive for cytokeratin and P40. The second consisted of nests of densely packed small round cells representing SNEC-positive neuroendocrine markers. The third was a solid sheet of anaplastic spindle cell proliferation, which was negative for the above markers. Oncogenic mutations such as FBXW7, TP53, and EGFR were detected in both SNEC and sarcomatoid carcinoma, and MYCL amplification was observed only in the SNEC component. This case highlights an extremely rare presentation of combined SNEC and sarcomatoid carcinoma arising from an inverted papilloma in the sinonasal sinus.

Invasive Stratified Mucin-producing Carcinoma (ISMC) of the Uterine Cervix: Clinicopathological and Molecular Characteristics With Special Emphasis on the First Description of Consistent Programmed Death-ligand 1 (PD-L1) Over-expression.

BACKGROUND/AIM: Invasive stratified mucin-producing carcinoma (ISMC) of the uterine cervix has been reported to be more aggressive than other subtypes of endocervical adenocarcinoma. We investigated the clinicopathological and molecular characteristics of eight ISMCs. PATIENTS AND METHODS: We reviewed the electronic medical records and pathology slides of eight patients with ISMC and conducted programmed death-ligand 1 (PD-L1) immunostaining and targeted sequencing. RESULTS: The patients were between 31 and 54 years. Six tumors were pure ISMCs, and two showed co-existing squamous cell carcinoma and usual-type endocervical adenocarcinoma. Lymph node metastases were detected in three cases. Three patients developed distant metastases to the adnexa, lungs, inguinal lymph nodes, and small intestine. Two patients experienced disease progression, and three developed postoperative local recurrences. All tumors showed PD-L1 over-expression, with a mean combined positive score of 73.8 (range=30-100). One tumor harbored erb-b2 receptor tyrosine kinase 2 amplification. CONCLUSION: ISMC of the uterine cervix exhibits a high risk of recurrence, metastasis, and resistance to chemoradiation therapy. PD-L1 over-expression was consistently observed in all ISMCs. This finding raises the possibility that patients with ISMC may benefit from PD-L1 immunotherapy.

External Validation of ALK and ROS1 Fusions Detected Using an Oncomine Comprehensive Assay.

BACKGROUND/AIM: This study aimed to assess the yield of an Oncomine comprehensive assay v3 (OCAv3)-based next-generation sequencing (NGS) analysis for detecting anaplastic lymphoma kinase (ALK) and c-ros oncogene 1 (ROS1) fusions in non-small cell lung cancer (NSCLC). PATIENTS AND METHODS: NGS data from 85 NSCLC cases were reviewed. ALK and ROS1 fusion status was compared to conventional tests. RESULTS: ALK or ROS1 fusion reads were detected in 17 NSCLC cases. Results in 10 NSCLC cases showed concordance with conventional tests, high-count fusion reads, a lack of mutually exclusive mutations of ALK or ROS1, and frequent signet-ring cell component. Seven NSCLC cases showing discordant results exhibited low to intermediate fusion read counts and mutations mutually exclusive from ALK or ROS1. CONCLUSION: Cases showing high-count fusion reads in OCAv3-based NGS have a strong possibility of carrying ALK or ROS1 fusion. Cases with low- to intermediate-count fusion reads should be interpreted with caution and may require additional confirmative tests.

TRPC3 and NALCN channels drive pacemaking in substantia nigra dopaminergic neurons.

Midbrain dopamine (DA) neurons are slow pacemakers that maintain extracellular DA levels. During the interspike intervals, subthreshold slow depolarization underlies autonomous pacemaking and determines its rate. However, the ion channels that determine slow depolarization are unknown. Here we show that TRPC3 and NALCN channels together form sustained inward currents responsible for the slow depolarization of nigral DA neurons. Specific TRPC3 channel blockade completely blocked DA neuron pacemaking, but the pacemaking activity in TRPC3 knock-out (KO) mice was perfectly normal, suggesting the presence of compensating ion channels. Blocking NALCN channels abolished pacemaking in both TRPC3 KO and wild-type mice. The NALCN current and mRNA and protein expression are increased in TRPC3 KO mice, indicating that NALCN compensates for TRPC3 currents. In normal conditions, TRPC3 and NALCN contribute equally to slow depolarization. Therefore, we conclude that TRPC3 and NALCN are two major leak channels that drive robust pacemaking in nigral DA neurons.