Pure Apocrine Intraductal Carcinoma of Salivary Glands: Reassessment of Molecular Underpinnings and Behavior.

BACKGROUND: Intraductal carcinoma (IDC) of the salivary glands is a confounding entity, our understanding of which continues to evolve. At least four forms have been elucidated based on histomorphology, immunophenotype, and molecular profile: (1) intercalated duct-like, S100/SOX10+ with frequent NCOA4::RET fusions; (2) oncocytic, S100/SOX10+ with TRIM33::RET, NCOA4::RET, and BRAF V600E; (3) apocrine, AR+ with PI3 kinase pathway mutations; and (4) mixed/hybrid intercalated duct-like/apocrine, with S100/SOX10+ and AR+ areas and frequent TRIM27::RET. The revelation that myoepithelial cells harbor the same fusion as luminal cells suggested that fusion-positive cases are not in situ carcinomas as previously believed. To this point, purely apocrine IDC with entirely intraductal growth has not been found to harbor fusions, but very few cases have been tested. METHODS: IDCs with pure apocrine morphology, entirely intraductal growth, and no precursor lesion (pleomorphic adenoma or sclerosing polycystic adenoma) were retrieved from the authors' archives. Several immunostains (S100, SOX10, GCDFP-15, AR, p40/SMA) and targeted next generation sequencing (NGS) panel including 1425 cancer-related genes were performed. RESULTS: Seven entirely IDC with pure apocrine type were collected. The cases arose in the parotid glands (mean, 1.9 cm) of 5 men and 2 women ranging from 51 to 84 years (mean, 69.7 years). Histologically, tumors consisted of rounded to angulated ductal cysts lined by epithelial cells with abundant finely granular eosinophilic cytoplasm and large nuclei with prominent nucleoli. Pleomorphism was mild to moderate, the mitotic rate was low, and necrosis was absent. Conventionally invasive foci or areas of intercalated duct-like morphology were not identified. In all cases, luminal cells were diffusely positive for AR and GCDFP-15 while negative for S100/SOX10, and the ducts were completely surrounded by myoepithelial cells highlighted by p40 and SMA. Molecular analysis was successful in 6 cases. Three harbored fusions: one with NCOA4::RET, another with STRN::ALK and one with both CDKN2A::CNTRL and TANC1::YY1AP1. The three fusion-negative cases all harbored HRAS mutations; additional mutations (PIK3CA, SPEN, ATM) were found in 2 of 3 cases. All patients were treated by surgery alone. Six of them are currently free of disease (follow up 12-190 months), but the case harboring NCOA4::RET developed lymph nodes metastasis in the form of a fusion-positive invasive salivary duct carcinoma. CONCLUSIONS: Purely apocrine IDC is a heterogeneous disease. A subset seems to be genetically similar to salivary duct carcinoma and may indeed represent carcinoma in situ. The other group harbors fusions, similar to other forms of IDC. Moreover, the occurrence of lymph node metastasis discredits the idea that any fusion-positive IDC with a complete myoepithelial cell layer has no metastatic potential. With the wide use of RET-and ALK-based targeted therapies, our findings further underscore the importance of fusion analysis for IDC.

Mucin-rich salivary gland tumors.

Salivary gland neoplasms characterized by abundant mucin production are rare but have long been recognized. Due to their scarcity, precise classification has long eluded these mucin-rich tumors. Recent molecular discoveries, however, have shed considerable light on the genetic underpinnings of mucin-rich salivary gland neoplasms. This manuscript will review the most up-to-date information on this fascinating group of salivary gland neoplasms.

Reticular Myxoid Odontogenic Neoplasm with Novel STRN::ALK Fusion: Report of 2 Cases in 3-Year-Old Males.

Odontogenic tumors represent a collection of entities ranging from hamartomas to destructive benign and malignant neoplasms. Occasionally, pathologists encounter gnathic lesions which clearly exhibit an odontogenic origin but do not fit within the confines of established diagnoses. Here, we describe two such odontogenic tumors, both affecting 3-year-old males. Each case presented as a destructive, radiolucent mandibular lesion composed of mesenchymal cells, some with unique multi-lobed nuclei, frequently arranged in a reticular pattern and supported by a myxoid stroma with focal laminations. Production of odontogenic hard tissues was also seen. Because of their unique microscopic features, both cases were investigated by next-generation sequencing and found to harbor the same STRN::ALK oncogene fusion. To our knowledge, these cases represent the first report of an odontogenic tumor with a STRN::ALK gene rearrangement. We propose the possibility that this neoplasm could be separate from other known odontogenic tumors. Both patients were treated with surgical resection and reconstruction. The prognosis of patients with this entity is currently uncertain but shall become more apparent over time as more cases are identified and followed.

The genomic and evolutionary landscapes of anaplastic thyroid carcinoma.

Anaplastic thyroid carcinoma is arguably the most lethal human malignancy. It often co-occurs with differentiated thyroid cancers, yet the molecular origins of its aggressivity are unknown. We sequenced tumor DNA from 329 regions of thyroid cancer, including 213 from patients with primary anaplastic thyroid carcinomas. We also whole genome sequenced 9 patients using multi-region sequencing of both differentiated and anaplastic thyroid cancer components. Using these data, we demonstrate thatanaplastic thyroid carcinomas have a higher burden of mutations than other thyroid cancers, with distinct mutational signatures and molecular subtypes. Further, different cancer driver genes are mutated in anaplastic and differentiated thyroid carcinomas, even those arising in a single patient. Finally, we unambiguously demonstrate that anaplastic thyroid carcinomas share a genomic origin with co-occurring differentiated carcinomas and emerge from a common malignant field through acquisition of characteristic clonal driver mutations.

Recurrent Wnt Pathway and ARID1A Alterations in Sinonasal Olfactory Carcinoma.

Sinonasal tumors with neuroepithelial differentiation, defined by neuroectodermal elements reminiscent of olfactory neuroblastoma (ONB) and epithelial features such as keratin expression or gland formation, are a diagnostically challenging group that has never been formally included in sinonasal tumor classifications. Recently, we documented that most of these neuroepithelial neoplasms have distinctive histologic and immunohistochemical findings and proposed the term "olfactory carcinoma" to describe these tumors. However, the molecular characteristics of olfactory carcinoma have not yet been evaluated. In this study, we performed targeted molecular profiling of 23 sinonasal olfactory carcinomas to further clarify their pathogenesis and classification. All tumors included in this study were composed of high-grade neuroectodermal cells that were positive for pankeratin and at least 1 specific neuroendocrine marker. A significant subset of cases also displayed rosettes and neurofibrillary matrix, intermixed glands with variable cilia, peripheral p63/p40 expression, and S100 protein-positive sustentacular cells. Recurrent oncogenic molecular alterations were identified in 20 tumors, including Wnt pathway alterations affecting CTNNB1 (n = 8) and PPP2R1A (n = 2), ARID1A inactivation (n = 5), RUNX1 mutations (n = 3), and IDH2 hotspot mutations (n = 2). Overall, these findings do demonstrate the presence of recurrent molecular alterations in olfactory carcinoma, although this group of tumors does not appear to be defined by any single mutation. Minimal overlap with alterations previously reported in ONB also adds to histologic and immunohistochemical separation between ONB and olfactory carcinoma. Conversely, these molecular findings enhance the overlap between olfactory carcinoma and sinonasal neuroendocrine carcinomas. A small subset of neuroepithelial tumors might better fit into the superseding molecular category of IDH2-mutant sinonasal carcinoma. At this point, sinonasal neuroendocrine and neuroepithelial tumors may best be regarded as a histologic and molecular spectrum that includes core groups of ONB, olfactory carcinoma, neuroendocrine carcinoma, and IDH2-mutant sinonasal carcinoma.

Keratocystoma: A Distinctive Salivary Gland Neoplasm Characterized by RUNX2 Rearrangements.

Keratocystoma is a rare salivary gland lesion that has been reported primarily in children and young adults. Because of a scarcity of reported cases, very little is known about it, including its molecular underpinnings, biological potential, and histologic spectrum. Purported to be a benign neoplasm, keratocystoma bears a striking histologic resemblance to benign lesions like metaplastic Warthin tumor on one end of the spectrum and squamous cell carcinoma on the other end. This overlap can cause diagnostic confusion, and it raises questions about the boundaries and definition of keratocystoma as an entity. This study seeks to utilize molecular tools to evaluate the pathogenesis of keratocystoma as well as its relationship with its histologic mimics. On the basis of targeted RNA sequencing (RNA-seq) results on a sentinel case, RUNX2 break-apart fluorescence in situ hybridization (FISH) was successfully performed on 4 cases diagnosed as keratocystoma, as well as 13 cases originally diagnosed as tumors that morphologically resemble keratocystoma: 6 primary squamous cell carcinomas, 3 metaplastic/dysplastic Warthin tumors, 2 atypical squamous cysts, 1 proliferating trichilemmal tumor, and 1 cystadenoma. RNA-seq and/or reverse transcriptase-PCR were attempted on all FISH-positive cases. Seven cases were positive for RUNX2 rearrangement, including 3 of 4 tumors originally called keratocystoma, 2 of 2 called atypical squamous cyst, 1 of 1 called proliferating trichilemmal tumor, and 1 of 6 called squamous cell carcinoma. RNA-seq and/or reverse transcriptase-PCR identified IRF2BP2::RUNX2 in 6 of 7 cases; for the remaining case, the partner remains unknown. The cases positive for RUNX2 rearrangement arose in the parotid glands of 4 females and 3 males, ranging from 8 to 63 years old (mean, 25.4 years; median, 15 years). The RUNX2 -rearranged cases had a consistent histologic appearance: variably sized cysts lined by keratinizing squamous epithelium, plus scattered irregular squamous nests, with essentially no cellular atypia or mitotic activity. The background was fibrotic, often with patchy chronic inflammation and/or giant cell reaction. One case originally called squamous cell carcinoma was virtually identical to the other cases, except for a single focus of small nerve invasion. The FISH-negative case that was originally called keratocystoma had focal cuboidal and mucinous epithelium, which was not found in any FISH-positive cases. The tumors with RUNX2 rearrangement were all treated with surgery only, and for the 5 patients with follow-up, there were no recurrences or metastases (1 to 120 months), even for the case with perineural invasion. Our findings solidify that keratocystoma is a cystic neoplastic entity, one which appears to consistently harbor RUNX2 rearrangements, particularly IRF2BP2::RUNX2 . Having a diagnostic genetic marker now allows for a complete understanding of this rare tumor. They arise in the parotid gland and affect a wide age range. Keratocystoma has a consistent morphologic appearance, which includes large squamous-lined cysts that mimic benign processes like metaplastic Warthin tumor and also small, irregular nests that mimic squamous cell carcinoma. Indeed, RUNX2 analysis has considerable promise for resolving these differential diagnoses. Given that one RUNX2 -rearranged tumor had focal perineural invasion, it is unclear whether that finding is within the spectrum of keratocystoma or whether it could represent malignant transformation. Most important, all RUNX2 -rearranged cases behaved in a benign manner.

Deep learning of cell spatial organizations identifies clinically relevant insights in tissue images.

Recent advancements in tissue imaging techniques have facilitated the visualization and identification of various cell types within physiological and pathological contexts. Despite the emergence of cell-cell interaction studies, there is a lack of methods for evaluating individual spatial interactions. In this study, we introduce Ceograph, a cell spatial organization-based graph convolutional network designed to analyze cell spatial organization (for example,. the cell spatial distribution, morphology, proximity, and interactions) derived from pathology images. Ceograph identifies key cell spatial organization features by accurately predicting their influence on patient clinical outcomes. In patients with oral potentially malignant disorders, our model highlights reduced structural concordance and increased closeness in epithelial substrata as driving features for an elevated risk of malignant transformation. In lung cancer patients, Ceograph detects elongated tumor nuclei and diminished stroma-stroma closeness as biomarkers for insensitivity to EGFR tyrosine kinase inhibitors. With its potential to predict various clinical outcomes, Ceograph offers a deeper understanding of biological processes and supports the development of personalized therapeutic strategies.

Comprehensive Molecular Characterization of Polymorphous Adenocarcinoma, Cribriform Subtype: Identifying Novel Fusions and Fusion Partners.

Polymorphous adenocarcinoma (PAC) is a common, usually low-grade salivary gland carcinoma. While conventional PACs are most associated with PRKD1 p.E710D hotspot mutations, the cribriform subtype is often associated with gene fusions in PRKD1, PRKD2, or PRKD3. These fusions have been primarily identified by fluorescence in situ hybridization (FISH) analysis, with a minority evaluated by next-generation sequencing (NGS). Many of the reported fusions were detected by break-apart FISH probes and therefore have unknown partners or were negative by FISH altogether. In this study, we aimed to further characterize the fusions associated with PAC with NGS. Fifty-four PACs (exclusively cribriform and mixed/intermediate types to enrich the study for fusion-positive cases) were identified and subjected to NGS. Fifty-one cases were successfully sequenced, 28 of which demonstrated gene fusions involving PRKD1, PRKD2, or PRKD3. There were 10 cases with the PRKD1 p.E710D mutation. We identified a diverse group of fusion partners, including 13 novel partners, 3 of which were recurrent. The most common partners for the PRKD genes were ARID1A and ARID1B. The wide variety of involved genes is unlike in other salivary gland malignancies and warrants a broader strategy of sequencing for molecular confirmation for particularly challenging cases, as our NGS study shows.

DNA Methylation Profiling Distinguishes Adamantinoma-Like Ewing Sarcoma From Conventional Ewing Sarcoma.

Adamantinoma-like Ewing sarcoma (ALES) has traditionally been considered a variant of Ewing sarcoma because it generally harbors EWSR1::FLI1 fusions despite showing diffuse positivity for keratins and p40. However, it has become increasingly recognized that different tumors can have identical translocations, including shared fusions between carcinomas and sarcomas, raising questions as to whether ALES might represent a separate entity. Using methylation profiling, we further explored the relationship between Ewing sarcoma and ALES. The archives of multiple institutions were searched for candidate cases of ALES. DNA methylation profiling was performed and results were compared to corresponding data from conventional Ewing sarcoma. Twelve cases of ALES (5 previously reported) were identified in 10 men and 2 women (aged 20-72 years; median age, 41.5 years). Cases included tumors arising in the parotid gland (3), sinonasal cavity (2), submandibular gland (2), thyroid gland (1), neck (1), gingiva (1), hypopharynx (1), and mandible (1). Histologic review consistently showed sheets and nests of basaloid cells within a fibromyxoid or hyalinized stroma. All tumors were positive for at least 1 keratin and CD99 expression, whereas all 10 cases tested were positive for p63 or p40; S100 protein expression was noted in 2 cases. Cases harbored either EWSR1::FLI1 fusions (n = 6), FUS::FLI1 fusions (n = 1), and/or EWSR1 rearrangements (n = 6). Methylation profiling was successful in 11/12 cases evaluated. Unsupervised clustering and dimensionality reduction (Uniform Manifold Approximation and Projection) of DNA methylation data revealed a distinct methylation cluster for all 11 cases, including the tumor with the FUS::FLI1 fusion, which clearly segregated them from the conventional Ewing sarcoma. Follow-up (n = 11, 1-154 months) revealed that 4 patients experienced recurrence and 6 developed metastatic disease. ALES demonstrates a distinct methylation signature from conventional Ewing sarcoma. This finding adds to the distinctive immunoprofile of ALES, suggesting that these 2 tumors should be considered distinct entities rather than histologic extremes of the same disease.

Deep Learning of Cell Spatial Organizations Identifies Clinically Relevant Insights in Tissue Images.

Recent advancements in tissue imaging techniques have facilitated the visualization and identification of various cell types within physiological and pathological contexts. Despite the emergence of cell-cell interaction studies, there is a lack of methods for evaluating individual spatial interactions. In this study, we introduce Ceograph, a novel cell spatial organization-based graph convolutional network designed to analyze cell spatial organization (i.e. the cell spatial distribution, morphology, proximity, and interactions) derived from pathology images. Ceograph identifies key cell spatial organization features by accurately predicting their influence on patient clinical outcomes. In patients with oral potentially malignant disorders, our model highlights reduced structural concordance and increased closeness in epithelial substrata as driving features for an elevated risk of malignant transformation. In lung cancer patients, Ceograph detects elongated tumor nuclei and diminished stroma-stroma closeness as biomarkers for insensitivity to EGFR tyrosine kinase inhibitors. With its potential to predict various clinical outcomes, Ceograph offers a deeper understanding of biological processes and supports the development of personalized therapeutic strategies.

Adamantinoma-like Ewing Sarcoma (ALES) May Harbor FUS Rearrangements : A Potential Diagnostic Pitfall.

Adamantinoma-like Ewing sarcoma (ALES) is a rare malignancy currently considered a variant of Ewing sarcoma with most known cases harboring EWSR1 rearrangements. Herein we present a series of 6 cases of EWSR1 -negative ALES. The tumors arose in the sinonasal tract (n=3), major salivary glands (submandibular gland=1; parotid=1), and anterior mediastinum (n=1) in patients ranging from 25 to 79 years of age. Most tumors were basaloid in appearance, growing in large nests separated by interlobular fibrosis without overt squamous pearls. However, 1 case closely resembled a well-differentiated neuroendocrine tumor with uniformly round nuclei, eosinophilic cytoplasm, and trabecular architecture. All cases were diffusely positive for pan-cytokeratin, p40 or p63, and CD99. A subset of cases showed diffuse reactivity for synaptophysin, including 1 sinonasal tumor which also demonstrated sustentacular S100 protein expression. Molecular testing showed FUS rearrangements in all cases. Gene partners included known ETS family members FEV (n=2) and FLI1 (n=1). Our results expand the molecular diagnostic considerations for ALES to include FUS rearrangements. We also show that ALES may harbor FUS :: FLI1 fusion, which has not been previously reported in the Ewing family of tumors. Furthermore, ALES may show unusual histologic and immunophenotypic features that can overlap with olfactory carcinoma including S100-positive sustentacular cells. ALES should be considered in the diagnostic differential of small round cell tumors and tumors with neuroendocrine differentiation with immunohistochemical workup to include p40 and CD99/NKX2.2.

Palisading Adenocarcinoma: A Morphologically Unique Salivary Gland Tumor With a Neuroendocrine-like Appearance and a Predilection for the Sublingual Glands of Women.

Adenocarcinoma, not otherwise specified (NOS) is a heterogenous group of salivary gland tumors that likely contains distinct tumors that have not yet been characterized. Indeed, in recent years, cases previously diagnosed as adenocarcinoma, NOS have been recategorized into novel tumor designations such as secretory carcinoma, microsecretory adenocarcinoma, and sclerosing microcystic adenocarcinoma. We sought to describe a distinctive, hitherto-undescribed salivary gland tumor encountered in the authors' practices. Cases were pulled from the surgical pathology archives of the authors' institutions. Histologic, immunohistochemical, and clinical findings were tabulated, and targeted next-generation sequencing was performed on all cases. Nine cases were identified, arising in 8 women and 1 man ranging from 45 to 74 years (mean, 56.7 y). Seven tumors (78%) arose in the sublingual gland, while 2 (22%) arose in the submandibular gland. The cases shared a distinctive morphologic appearance. They were biphasic, with ducts scattered among a predominant polygonal cell with round nuclei, prominent nucleoli, and pale eosinophilic cytoplasm. These cells were arranged as trabeculae and palisaded as pseudorosettes around hyalinized stroma and vessels, resembling a neuroendocrine tumor. Four of the cases were well-circumscribed, while the remaining 5 showed infiltrative growth including perineural invasion in 2 (22%) and lymphovascular invasion in 1 (11%). Mitotic rates were low (mean, 2.2/10 HPFs); necrosis was absent. By immunohistochemistry, the predominant cell type was strongly positive for CD56 (9 of 9) and variably positive for pan-cytokeratin (AE1/AE3) (7 of 9) with patchy S100 (4 of 9), but negative for synaptophysin (0 of 9) and chromogranin (0 of 9), while the ducts were strongly positive for pan-cytokeratin (AE1/AE3) (9 of 9) and CK5/6 (7 of 7). Next-generation sequencing did not reveal any fusions or obvious driver mutations. All cases were resected surgically, with external beam radiation also done in 1 case. Follow-up was available in 8 cases; there were no metastases or recurrences after 4 to 160 months (mean, 53.1 mo). A dual population of scattered ducts with a predominance of CD56-positive neuroendocrine-like cells characterizes a unique salivary gland tumor which is often encountered in the sublingual glands of women, for which we propose the term "palisading adenocarcinoma." Although the tumor was biphasic and had a neuroendocrine-like appearance, it lacked convincing immunohistochemical evidence of myoepithelial or neuroendocrine differentiation. Although a subset showed unequivocally invasive growth, this tumor appears to behave in an indolent manner. Moving forward, recognition of palisading adenocarcinoma and its separation from other salivary adenocarcinomas, NOS will facilitate a better understanding of the characteristics of this previously unrecognized tumor.

Deep learning in digital pathology for personalized treatment plans of cancer patients.

Over the past decade, many new cancer treatments have been developed and made available to patients. However, in most cases, these treatments only benefit a specific subgroup of patients, making the selection of treatment for a specific patient an essential but challenging task for oncologists. Although some biomarkers were found to associate with treatment response, manual assessment is time-consuming and subjective. With the rapid developments and expanded implementation of artificial intelligence (AI) in digital pathology, many biomarkers can be quantified automatically from histopathology images. This approach allows for a more efficient and objective assessment of biomarkers, aiding oncologists in formulating personalized treatment plans for cancer patients. This review presents an overview and summary of the recent studies on biomarker quantification and treatment response prediction using hematoxylin-eosin (H&E) stained pathology images. These studies have shown that an AI-based digital pathology approach can be practical and will become increasingly important in improving the selection of cancer treatments for patients.

Adenoid Cystic Carcinoma With Striking Tubular Hypereosinophilia: A Unique Pattern Associated With Nonparotid Location and Both Canonical and Novel EWSR1::MYB and FUS::MYB Fusions.

The classification of salivary gland tumors is ever-evolving with new variants of tumors being described every year. Next-generation sequencing panels have helped to prove and disprove prior assumptions about tumors' relationships to one another, and have helped refine this classification. Adenoid cystic carcinoma (AdCC) is one of the most common salivary gland malignancies and occurs at all major and minor salivary gland and seromucous gland sites. Most AdCC are predominantly myoepithelial and basaloid with variable cribriform, tubular, and solid growth. The luminal tubular elements are often less conspicuous. AdCC has largely been characterized by canonical MYB fusions, with MYB::NFIB and rarer MYBL1::NFIB. Anecdotal cases of AdCC, mostly in nonmajor salivary gland sites, have been noted to have unusual patterns, including squamous differentiation and macrocystic growth. Recently, this has led to the recognition of a subtype termed "metatypical adenoid cystic carcinoma." Another unusual histology that we have seen with a wide range of architecture, is striking tubular hypereosinophilia. The hypereosinophilia and luminal cell prominence is in stark contrast to the vast majority of AdCC that are basaloid and myoepithelial predominant. A total of 16 cases with tubular hypereosinophilia were collected, forming morular, solid, micropapillary, and glomeruloid growth, and occasionally having rhabdoid or Paneth-like cells. They were subjected to molecular profiling demonstrating canonical MYB::NFIB (5 cases) and MYBL1::NFIB (2 cases), as well as noncanonical EWSR1::MYB (2 cases) and FUS::MYB (1 case). The remaining 6 cases had either no fusion (3 cases) or failed sequencing (3 cases). All cases were present in nonmajor salivary gland sites, with seromucous glands being the most common. These include sinonasal tract (7 cases), laryngotracheal (2 cases), external auditory canal (2 cases), nasopharynx (1 case), base of tongue (2 cases), palate (1 case), and floor of mouth (1 case). A tissue microarray of 102 conventional AdCC, including many in major salivary gland sites was examined for EWSR1 and FUS by fluorescence in situ hybridization and showed that these novel fusions were isolated to this histology and nonmajor salivary gland location. In summary, complex and striking tubular hypereosinophilia and diverse architectures are present within the spectrum of AdCC, particularly in seromucous gland sites, and may show variant EWSR1/FUS::MYB fusions.

Microsecretory Adenocarcinoma of Salivary Glands.

Salivary gland classification has benefitted immensely from the growing field of molecular diagnostics. Microsecretory adenocarcinoma, a novel salivary gland malignancy recently included in the fifth edition of the World Health Organization Classifications of Head and Neck Tumours, is one such example. This novel entity was discovered among the umbrella category of adenocarcinoma, not otherwise specified, using a combination of careful histologic analysis and advanced molecular techniques. Its strikingly characteristic histologic features including subtle infiltration, flattened tubules, and abundant blue secretions highlight the necessity of meticulous morphologic observation, even in the age of increased molecular testing. It harbors a recurrent novel MEF2C::SS18 gene fusion, which is amenable to fluorescence in situ hybridization analysis. It presents predominantly in the oral cavity with a propensity for the palate and the majority are thus far low grade, clinically indolent tumors. The recent discovery of a cutaneous corollary to this tumor suggests that the spectrum of its presentation has not entirely been delineated. In the context of expanding molecular testing, pathologists are tasked to sift through constantly evolving molecular data to incorporate diagnostically relevant tests into their practice. In salivary gland pathology, the example of microsecretory adenocarcinoma demonstrates that primary histologic assessment, with sensible use of immunohistochemistry, can lead to accurate diagnosis. Molecular testing is beneficial in cases with significant diagnostic challenges.

Evaluation of the Incidence of Human Papillomavirus-Associated Squamous Cell Carcinoma of the Sinonasal Tract Among US Adults.

This case series assesses the incidence of human papillomavirus (HPV)-associated sinonasal squamous cell carcinoma (SNSCC) and the prevalence of HPV-positive SNSCC among US adults.

Deep learning-based pathology image analysis predicts cancer progression risk in patients with oral leukoplakia.

BACKGROUND: Oral leukoplakia (OL) is associated with an increased risk for oral cancer (OC) development. Prediction of OL cancer progression may contribute to decreased OC morbidity and mortality by favoring early intervention. Current OL progression risk assessment approaches face large interobserver variability and is weakly prognostic. We hypothesized that convolutional neural networks (CNN)-based histology image analyses could accelerate the discovery of better OC progression risk models. METHODS: Our CNN-based oral mucosa risk stratification model (OMRS) was trained to classify a set of nondysplastic oral mucosa (OM) and a set of OC H&E slides. As a result, the OMRS model could identify abnormal morphological features of the oral epithelium. By applying this model to OL slides, we hypothesized that the extent of OC-like features identified in the OL epithelium would correlate with its progression risk. The OMRS model scored and categorized the OL cohort (n = 62) into high- and low-risk groups. RESULTS: OL patients classified as high-risk (n = 31) were 3.98 (95% CI 1.36-11.7) times more likely to develop OC than low-risk ones (n = 31). Time-to-progression significantly differed between high- and low-risk groups (p = 0.003). The 5-year OC development probability was 21.3% for low-risk and 52.5% for high-risk patients. The predictive power of the OMRS model was sustained even after adjustment for age, OL site, and OL dysplasia grading (HR = 4.52, 1.5-13.7). CONCLUSION: The ORMS model successfully identified OL patients with a high risk of OC development and can potentially benefit OC early diagnosis and prevention policies.

A Low-grade Sinonasal Sarcoma Harboring EWSR1::BEND2: Expanding the Differential Diagnosis of Sinonasal Spindle Cell Neoplasms.

BACKGROUND: Molecular diagnostics has greatly refined sinonasal tumor pathology over the past decade. While much of the attention has focused on carcinomas, it is becoming clear that there are emerging mesenchymal neoplasms which have previously defied classification. METHODS: Here, we present a 33-year-old woman with a multiply recurrent sinonasal spindle cell tumor exhibiting distinctive features, and not easily classifiable into a specific category. RESULTS: The hypercellular tumor was composed of plump spindled cells, with uniform vesicular chromatin arranged as vague fascicles around a prominent hemangiopericytoma-like vasculature. The mitotic rate was brisk at 10 per 10 high power fields. By immunohistochemistry, it was only positive for EMA (focal) and SATB2 (diffuse, weak). Fusion analysis uncovered EWSR1::BEND2, a fusion which is best known for being seen in astroblastoma, but which has not yet been reported in sarcomas. CONCLUSION: This case underscores the utility of fusion analysis when confronted with a sinonasal spindle cell neoplasm which does not neatly fit into any specific category. It remains to be seen if EWSR1::BEND2 sinonasal sarcoma represents a distinct entity.