Defining the relationship of salivary gland malignancies to novel cell subpopulations in human salivary glands using single nucleus RNA-sequencing

Salivary glands have essential roles in maintaining oral health, mastication, taste and speech, by secreting saliva. Salivary glands are composed of several types of cells, and each cell type is predicted to be involved in the carcinogenesis of different types of cancers including adenoid cystic carcinoma (ACC), acinic cell carcinoma (AciCC), salivary duct carcinoma (SDC), myoepithelial carcinoma (MECA) and other histology. In our study, we performed single nucleus RNA-seq on three human salivary gland samples to clarify the gene expression profile of each complex cellular component of the salivary glands and related these expression patterns to expression found in salivary gland cancers (SGC) to infer cell of origin. By single nucleus RNA-seq, salivary gland cells were stratified into four clusters: acinar cells, ductal cells 1, ductal cells 2 and myoepithelial cells/stromal cells. The localization of each cell group was verified by IHC of each cluster marker gene, and one group of ductal cells was found to represent intercalated ductal cells labeled with HES1. Furthermore, in comparison with SGC RNA-seq data, acinar cell markers were upregulated in AciCC, but downregulated in ACC and ductal cell markers were upregulated in SDC but downregulated in MECA, suggesting that markers of origin are highly expressed in some SGC. Cell type expressions in specific SGC histology are similar to those found in normal salivary gland populations, indicating a potential etiologic relationship.

Evaluation and Management of Testicular Cancer After Late Relapse

A 41-year-old man presented to his primary care physician with a 1-month history of left neck adenopathy in the context of a history of nonseminomatous germ cell tumors (NSGCTs). In 2011, the patient was treated for stage IB (T2N0M0S0) right-sided NSGCTs of the testis, which were 95% embryonal and 5% yolk sac tumors. He underwent a right radical orchiectomy and was followed until 2022 without recurrence. In the work-up for his adenopathy, laboratory results for human chorionic gonadotropin, lactate dehydrogenase, and α-fetoprotein were normal. CT scans confirmed clustered enlarged lymph nodes in the left lower spinal accessory posterior triangle, enlarged left lower neck lymph nodes, and several foci of enlarged left retroperitoneal periaortic lymph nodes. Fine needle aspiration of a left neck lymph node identified malignant tumor cells. A left neck dissection showed embryonal carcinoma in 12 of 28 nodes. Immunostaining showed the tumor cells were positive for SALL4 and CD30 but negative for CD117. This patient likely had a contralateral late relapse of his original right NSGCT after 11 years of remission. The patient's original cancer was on the right side, with recurrence surrounding the aorta on the contralateral side, representing an atypical pattern of spread.

Multidimensional biomarker predicts disease control in response to immunotherapy in recurrent or metastatic head and neck squamous-cell carcinoma

PURPOSE

Anti-PD-1 therapy provides clinical benefit in 40-50% of patients with relapsed and/or metastatic head and neck squamous cell carcinoma (RM-HNSCC). Selection of anti- PD-1 therapy is typically based on patient PD-L1 immunohistochemistry (IHC) which has low specificity for predicting disease control. Therefore, there is a critical need for a clinical biomarker that will predict clinical benefit to anti-PD-1 treatment with high specificity.

METHODS

Clinical treatment and outcomes data for 103 RM-HNSCC patients were paired with RNA-sequencing data from formalin-fixed patient samples. Using logistic regression methods, we developed a novel biomarker classifier based on expression patterns in the tumor immune microenvironment to predict disease control with monotherapy PD-1 inhibitors (pembrolizumab and nivolumab). The performance of the biomarker was internally validated using out-of-bag methods.

RESULTS

The biomarker significantly predicted disease control (65% in predicted non-progressors vs. 17% in predicted progressors, p < 0.001) and was significantly correlated with overall survival (OS; p = 0.004). In addition, the biomarker outperformed PD-L1 IHC across numerous metrics including sensitivity (0.79 vs 0.64, respectively; p = 0.005) and specificity (0.70 vs 0.61, respectively; p = 0.009).

CONCLUSION

This novel assay uses tumor immune microenvironment expression data to predict disease control and OS with high sensitivity and specificity in patients with RM-HNSCC treated with anti-PD-1 monotherapy.

B3 thymoma mimicking poorly differentiated thyroid carcinoma: Diagnostic pitfalls of anterior mediastinal mass fine needle aspiration

B3 thymoma is a rare malignant type of thymic epithelial neoplasm found in the anterior mediastinum. Diagnosis of thymoma from fine needle aspiration (FNA) can be challenging due to the infrequency of sampling and its morphologic overlap with other entities such as squamous cell carcinoma, lymphoma or thyroid carcinoma. We report a case of B3 thymoma mimicking poorly differentiated thyroid carcinoma. We present its diagnostic pitfalls on cytology specimens, especially where it concerns identifying the correct location of the lesion, discuss the differential diagnosis, and correlation with the corresponding surgical resection specimen. A neck computed tomography angiogram (CTA) revealed a partially calcified 2.1 cm mass inferior to the left thyroid lobe in a 51 yr old woman being evaluated for stroke/TIA symptoms. She was referred for evaluation of the lesion. On the initial FNA and core needle biopsy, the lesion showed high-grade epithelioid cells with abundant lymphocytic infiltration and occasional necrosis, and was diagnosed as a high-grade carcinoma, favored to represent a poorly differentiated thyroid carcinoma considering the location on imaging. The patient subsequently underwent total thyroidectomy, central neck dissection, and thymectomy. Final surgical pathologic diagnosis indicated a type B3 thymoma. Due to the infrequency of sampling, thymoma poses a diagnostic challenge on preoperative FNA or core needle biopsy. Herein, we present a case of B3 thymoma with a preoperative cytologic specimen that consisted of hyperchromatic sheets of epithelioid tumor cells with a background of lymphocytes without definitive follicular cells or colloid. The core needle biopsy and cell block material showed abundant necrosis, intermixed lymphocytes and neoplastic epithelial cells with strong positive staining for pan-keratin and p40. The cytology and core needle biopsy material were interpreted as representing a probable thyroid neoplasm and raised a broad differential including anaplastic thyroid carcinoma, poorly differentiated thyroid carcinoma with squamous features, metastatic squamous carcinoma, and metastatic carcinoma to a lymph node. The final surgical resection specimen showed a B3 type-thymoma.

Smarcd3 is an epigenetic modulator of the metabolic landscape in pancreatic ductal adenocarcinoma

Pancreatic cancer is characterized by extensive resistance to conventional therapies, making clinical management a challenge. Here we map the epigenetic dependencies of cancer stem cells, cells that preferentially evade therapy and drive progression, and identify SWI/SNF complex member SMARCD3 as a regulator of pancreatic cancer cells. Although SWI/SNF subunits often act as tumor suppressors, we show that SMARCD3 is amplified in cancer, enriched in pancreatic cancer stem cells and upregulated in the human disease. Diverse genetic mouse models of pancreatic cancer and stage-specific Smarcd3 deletion reveal that Smarcd3 loss preferentially impacts established tumors, improving survival especially in context of chemotherapy. Mechanistically, SMARCD3 acts with FOXA1 to control lipid and fatty acid metabolism, programs associated with therapy resistance and poor prognosis in cancer. These data identify SMARCD3 as an epigenetic modulator responsible for establishing the metabolic landscape in aggressive pancreatic cancer cells and a potential target for new therapies.

A Young Man Presenting With Tongue Lesions

A 19-year-old man presented with tongue pain of 3 months’ duration and a raised tongue lesion with slightly hairy appearance. What is your diagnosis?

Enteroendocrine Cell Formation Is an Early Event in Pancreatic Tumorigenesis

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with a 5-year survival rate of only 11%, due, in part, to late diagnosis, making the need to understand early events in tumorigenesis critical. Acinar-to-ductal metaplasia (ADM), when not resolved, is a PDAC precursor. Recently, we showed that ADM is constituted by a heterogenous population of cells, including hormone-producing enteroendocrine cells (EECs: gamma, delta, epsilon, and enterochromaffin cells). In this study, we employed histopathological techniques to identify and quantify the abundance of EEC subtypes throughout pancreatic tumorigenesis in mouse models and human disease. We found that EECs are most abundant in ADM and significantly decrease with lesion progression. Co-immunofluorescence identifies distinct lineages and bihormonal populations. Evaluation of EEC abundance in mice lacking Pou2f3 demonstrates that the tuft cell master regulator transcription factor is not required for EEC formation. We compared these data to human neoplasia and PDAC and observed similar trends. Lastly, we confirm that EECs are a normal cellular compartment within the murine and human pancreatic ductal trees. Altogether, these data identify EECs as a cellular compartment of the normal pancreas, which expands early in tumorigenesis and is largely lost with disease progression.

Transjugular liver biopsy for Fontan associated liver disease surveillance: Technique, outcomes and hemodynamic correlation

BACKGROUND

Fontan associated liver disease (FALD) is attributed to the limitations of the Fontan circulation, resulting in congestive hepatopathy. The technique and outcomes of transjugular liver biopsies (TJLB) in Fontan patients warrant definition as part of a rigorous FALD surveillance program.

METHOD

Four year review of patients with Fontan physiology who underwent a TJLB during surveillance catheterizations. Biopsy site, technique, histology, angiography, hemodynamics, and complications were reviewed to assess correlation of biopsy scores with simultaneously obtained catheterization hemodynamics.

RESULTS

125 patients with a TJLB from 10/1/14 to 5/1/18. Median age 17 years (2-50.5). Technical success 100% (125/125), all samples diagnostic. 17% (21) accessed via the left internal jugular vein, secondary to right IJ occlusion or Heterotaxy syndrome. No patients had superior compartment obstruction preventing transjugular approach. 3.2% complication rate (4/125). Complications were early in the experience, including capsular perforation (2), renal hematoma (1) and hemobilia (1), all without long-term effect and all avoidable. After standardized entry/exit angiography was adopted, no further complications noted. There is a significant correlation between the newly described modified Ishak congestive hepatic fibrosis (ICHF) score with mean Fontan pressure, time from Fontan and cardiac index.

CONCLUSIONS

TJLB is an alternate method for obtaining critical FALD surveillance data, with lower complication rates that traditional techniques. Vascular anomalies in Fontan physiology appear common and warrant pre-biopsy assessment. There is a significant correlation between biopsy score, time from Fontan, mean Fontan pressure and cardiac index.

Tuft Cells Inhibit Pancreatic Tumorigenesis in Mice by Producing Prostaglandin D2

BACKGROUND & AIMS

Development of pancreatic ductal adenocarcinoma (PDA) involves acinar to ductal metaplasia and genesis of tuft cells. It has been a challenge to study these rare cells because of the lack of animal models. We investigated the role of tuft cells in pancreatic tumorigenesis.

METHODS

We performed studies with LSL-KrasG12D/+;Ptf1aCre/+ mice (KC; develop pancreatic tumors), KC mice crossed with mice with pancreatic disruption of Pou2f3 (KPouC mice; do not develop tuft cells), or mice with pancreatic disruption of the hematopoietic prostaglandin D synthase gene (Hpgds, KHC mice) and wild-type mice. Mice were allowed to age or were given caerulein to induce pancreatitis; pancreata were collected and analyzed by histology, immunohistochemistry, RNA sequencing, ultrastructural microscopy, and metabolic profiling. We performed laser-capture dissection and RNA-sequencing analysis of pancreatic tissues from 26 patients with pancreatic intraepithelial neoplasia (PanIN), 19 patients with intraductal papillary mucinous neoplasms (IPMNs), and 197 patients with PDA.

RESULTS

Pancreata from KC mice had increased formation of tuft cells and higher levels of prostaglandin D2 than wild-type mice. Pancreas-specific deletion of POU2F3 in KC mice (KPouC mice) resulted in a loss of tuft cells and accelerated tumorigenesis. KPouC mice had increased fibrosis and activation of immune cells after administration of caerulein. Pancreata from KPouC and KHC mice had significantly lower levels of prostaglandin D2, compared with KC mice, and significantly increased numbers of PanINs and PDAs. KPouC and KHC mice had increased pancreatic injury after administration of caerulein, significantly less normal tissue, more extracellular matrix deposition, and higher PanIN grade than KC mice. Human PanIN and intraductal papillary mucinous neoplasm had gene expression signatures associated with tuft cells and increased expression of Hpgds messenger RNA compared with PDA.

CONCLUSIONS

In mice with KRAS-induced pancreatic tumorigenesis, loss of tuft cells accelerates tumorigenesis and increases the severity of caerulein-induced pancreatic injury, via decreased production of prostaglandin D2. These data are consistent with the hypothesis that tuft cells are a metaplasia-induced tumor attenuating cell type.

A case of mistaken identity: Saksenaea vasiformis of the orbit

The authors describe a rare presentation of invasive fungal rhino-orbital cellulitis caused by Saksenaea vasiformis in an immunocompetent child. The patient was initially diagnosed and treated as Mucoraceae, which has a high mortality rate and is primarily seen in immunocompromised patients. Though of the same order, Mucorales, the families Mucoraceae and Saksenaeacae, may be difficult to differentiate on histologic examination and must be distinguished by fungal culture and speciation. Our patient responded well to sino-orbital debridement and systemic treatment with amphotericin and posaconazole.

SAT-352 Severe Primary Hyperparathyroidism, Hypercalcemic Crisis, Acute Pancreatitis and Fatality: Complications of Atypical Parathyroid Adenoma, a Case Report

BACKGROUND: Atypical parathyroid adenomas (APAs) are a controversial and rare entity. These tumors show some features of carcinomas including adherence to adjacent structures, banding fibrosis, mitotic activity, and tumor cells trapped within capsule; however, they lack definitive capsular, vascular, or perineural invasion. Patients are often asymptomatic, or have vague symptoms such as fatigue. Studies and literature have reported that the elevation in parathyroid hormone (PTH) and calcium levels in APAs are intermediate between those of adenomas and carcinomas, and that the clinical course is generally benign. Clinical Case: A 41-year old woman with diabetes mellitus, Hashimoto’s thyroiditis, and obesity was noted to have mild asymptomatic hypercalcemia during routine tests performed at an outside hospital several months prior to presentation. A few weeks prior to presentation, she started complaining of anorexia, nausea, vomiting and abdominal pain. At the time of presentation, she was critically-ill with a picture of severe acute pancreatitis. Laboratory tests showed hypercalcemia (13.9 mg/dL, normal 8.5-10.6 mg/dL) and elevated lipase (1134 U/L, normal 13-60 U/L); however, a magnetic resonance cholangiopancreatography showed no biliary obstruction. Further testing revealed markedly elevated PTH (>5000 pg/ml, normal 15-65 pg/ml), and subsequent neck ultrasound showed a solitary mass on the left side of the neck. Despite maximum medical treatment, the patient continued to rapidly decompensate and passed away rapidly. Autopsy examination revealed a picture of severe acute pancreatitis including a markedly enlarged necrotic pancreas (360 grams, normal: 60-100 grams), extensive omental fat necrosis, ascites, and dusky discoloration of the abdominal organs. A well-circumscribed mass (6.6 x 3.5 x 1.5 cm) was found on the superior aspect of the left thyroid lobe. The tumor showed parathyroid cell proliferation admixed with banding fibrosis, no unequivocal invasion into the surrounding capsule, blood vessels or perineural spaces, and no evidence of lymph node involvement or distant metastasis, consistent with a diagnosis of APA. Her cause of death was the left neck APA and its associated sequelae of significant hypercalcemia and acute pancreatitis. Conclusion: This patient had asymptomatic hypercalcemia for months prior to presentation with PTH/hypercalcemic crisis, highlighting the importance of ruling out primary hyperparathyroidism in the assessment of patients with asymptomatic hypercalcemia. While it’s generally appreciated that parathyroid carcinomas usually cause more profound hypercalcemia and are more likely to cause fatality from metabolic complications, and that APAs follow a generally more benign course, this case shows that APAs can grow into significantly large lesions and could follow a severe and abrupt clinical course if not surgically removed.

Exercise MRI highlights heterogeneity in cardiovascular mechanics among patients with Fontan circulation: proposed protocol for routine evaluation

Single ventricle physiology and palliation via the Fontan operation lead to a series of cardiovascular changes. In addition, organs such as the kidneys and liver have been shown to experience insults and subsequent injury. This has led to routine surveillance of patients. We present findings from a small cohort of patients that was deeply phenotyped to illustrate the need for comprehensive evaluation. A cohort of four Fontan patients with fairly high cardiovascular function was recruited 5–10 years post-Fontan. Patients underwent a rigorous clinical work-up after which a research MRI scan was performed during which (I) data were obtained during exercise to evaluate changes in stroke volume during supine exercise and (II) magnetic resonance angiograms with phase-contrast images were obtained for computational modeling of flows through the Fontan circulation at rest. Clinical measures were consistent with a fairly homogeneous high function cohort (peak oxygen consumption >20 mL/kg/min, robust response to exercise, peak ventilatory efficiency below levels associated with heart failure, MR-derived ejection fraction >50%). Liver evaluation did not reveal clear signs of cirrhosis or extensive fibrosis. However, we observed considerable variability (27–162%) in the increase in stroke index with exercise [100%±64% increase, 53.9±17.4 mL/beat m² (rest), 101.1±20.7 mL/beat m², (exercise)]. Computational flow modeling at rest in two patients also showed marked differences in flow distribution and shear stress. We report marked differences in both changes in stroke index during an exercise MRI protocol as well as computational flow patterns at rest suggesting different compensation strategies may be associated with high functioning Fontan patients. The observed heterogeneity illustrates the need for deep phenotyping to capture patient-specific adaptive mechanisms.

Mutation profile of high-grade appendiceal mucinous neoplasm

AIMS

High-grade appendiceal mucinous neoplasm (HAMN) was recently proposed as a disease entity histologically analogous to low-grade appendiceal mucinous neoplasm (LAMN), but characterised by high-grade cytological atypia. The pathogenesis and clinical features of HAMN have not been fully elucidated.

METHODS AND RESULTS

Nine cases of HAMN, eight LAMN, 10 appendiceal mucinous adenocarcinomas (MACA) and five appendiceal serrated polyps resected between 2008 and 2017 contributed by three medical centres underwent targeted next-generation sequencing of 50 cancer-related genes. The patients in each category had similar profiles with respect to gender, age, tumour stage and follow-up intervals. Both LAMN and HAMN harboured mutations of KRAS [nine of nine and eight of eight (100%), respectively] and GNAS [five of eight (63%) and five of nine (56%), respectively] in significantly higher proportions than MACA [KRAS, seven of 10 (70%, P = 0.04); GNAS: one of 10 (10%, P = 0.02)] and serrated polyps [KRAS, one of five (20%, P = 0.0007); GNAS: none of five (0%, P = 0.04)]. Four cases of HAMN, but none of LAMN, harboured mutations of TP53 [four of nine (44%)] and/or ATM [two of nine (22%)]. Three cases of HAMN (33%) showed extra-appendiceal spread with retention of the same mutational profiles in the intra- and extra-appendiceal components. The 10 cases of MACA harboured a similar prevalence of TP53 mutations (n = 5, 50%) as HAMN but, unlike LAMN and HAMN, some harboured mutations in PIK3CA, APC, FBXW7, PTEN and SMAD4.

CONCLUSIONS

HAMN and LAMN share high rates of KRAS and GNAS co-mutations supporting a common histogenesis and distinguishing them from MACA. Acquisition of TP53 or ATM mutations by HAMN may drive its progression to a more advanced phenotype.

Overinterpretation is common in pathological diagnosis of appendix cancer during patient referral for oncologic care

CONTEXT

Low-grade appendiceal mucinous neoplasm (LAMN) and appendiceal adenocarcinoma are known to cause the majority of pseudomyxoma peritonei (PMP, i.e. mucinous ascites); however, recognition and proper classification of these neoplasms can be difficult despite established diagnostic criteria.

OBJECTIVE

To determine the pathological diagnostic concordance for appendix neoplasia and related lesions during patient referral to an academic medical center specialized in treating patients with PMP.

DESIGN

The anatomic pathology laboratory information system was searched to identify cases over a two-year period containing appendix specimens with mucinous neoplasia evaluated by an outside pathology group and by in-house slide review at a single large academic medical center during patient referral.

RESULTS

161 cases containing appendix specimens were identified over this period. Forty-six of 161 cases (28.6%) contained appendiceal primary neoplasia or lesions. Of these, the originating pathologist diagnosed 23 cases (50%) as adenocarcinoma and 23 cases (50%) as LAMN; however, the reference pathologist diagnosed 29 cases (63.0%) as LAMN, 13 cases (28.3%) as adenocarcinoma, and 4 cases (8.7%) as ruptured simple mucocele. Importantly, for cases in which the originating pathologist rendered a diagnosis of adenocarcinoma, the reference pathologist rendered a diagnosis of adenocarcinoma (56.5%, 13 of 23), LAMN (39.1%, 9 of 23), or simple mucocele (4.3%, 1 of 23). The overall diagnostic concordance rate for these major classifications was 71.7% (33 of 46) with an unweighted observed kappa value of 0.48 (95% CI, 0.27-0.69), consistent with moderate interobserver agreement. All of the observed discordance (28.3%) for major classifications could be attributed to over-interpretation. In addition, the majority of LAMN cases (65.5%) had potential diagnostic deficiencies including over-interpretation as adenocarcinoma and lacking or discordant risk stratification (i.e. documentation of extra-appendiceal neoplastic epithelium).

CONCLUSIONS

Appendiceal mucinous lesions remain a difficult area for appropriate pathological classification with substantial discordance due to over-interpretation in this study. The findings highlight the critical need for recognition and application of diagnostic criteria regarding these tumors. Recently published consensus guidelines and a checklist provided herein may help facilitate improvement of diagnostic concordance and thereby reduce over-interpretation and potential overtreatment. Further studies are needed to determine the extent of this phenomenon and its potential clinical impact.

Review article: the global emergence of Helicobacter pylori antibiotic resistance

BACKGROUND

Helicobacter pylori is one of the most prevalent global pathogens and can lead to gastrointestinal disease including peptic ulcers, gastric marginal zone lymphoma and gastric carcinoma.

AIM

To review recent trends in H. pylori antibiotic resistance rates, and to discuss diagnostics and treatment paradigms.

METHODS

A PubMed literature search using the following keywords: Helicobacter pylori, antibiotic resistance, clarithromycin, levofloxacin, metronidazole, prevalence, susceptibility testing.

RESULTS

The prevalence of bacterial antibiotic resistance is regionally variable and appears to be markedly increasing with time in many countries. Concordantly, the antimicrobial eradication rate of H. pylori has been declining globally. In particular, clarithromycin resistance has been rapidly increasing in many countries over the past decade, with rates as high as approximately 30% in Japan and Italy, 50% in China and 40% in Turkey; whereas resistance rates are much lower in Sweden and Taiwan, at approximately 15%; there are limited data in the USA. Other antibiotics show similar trends, although less pronounced.

CONCLUSIONS

Since the choice of empiric therapies should be predicated on accurate information regarding antibiotic resistance rates, there is a critical need for determination of current rates at a local scale, and perhaps in individual patients. Such information would not only guide selection of appropriate empiric antibiotic therapy but also inform the development of better methods to identify H. pylori antibiotic resistance at diagnosis. Patient-specific tailoring of effective antibiotic treatment strategies may lead to reduced treatment failures and less antibiotic resistance.