Low-grade non-intestinal-type sinonasal adenocarcinoma: a histologically distinctive but molecularly heterogeneous entity

Sinonasal adenoid cystic carcinomas accompanied by seromucinous hamartoma and/or atypical sinonasal glands arising from seromucinous hamartoma: insight into their histogenesis

The pathology of reactive, dysplastic, and neoplastic sinonasal seromucinous glands is complex, and their contribution to tumorigenesis of sinonasal carcinomas remains controversial. In our practice, we have observed the presence of respiratory epithelial adenomatoid hamartomas (REAH) and seromucinous hamartomas (SH) associated with adenoid cystic carcinomas (AdCC) in a subset of cases. In many of these cases, genuine atypical features and dysplastic characteristics of the glands were noted at the interface of SH and AdCC. To investigate this phenomenon further, 88 sinonasal AdCC cases were selected from the authors' files and analyzed histologically, immunohistochemically, and genetically searching for MYB/MYBL1 and NFIB gene fusions. HPV testing was also performed. Univariate statistical analysis was conducted on our cohort. Thirty-one cases (35%) showed features of atypical sinonasal glands arising in SH (ASGSH) at the SH-AdCC interface, characterized by bilayered epithelium, architectural disarray, mild nuclear polymorphism, and atypia, sometimes with colloid-like material in the lumen. The MYB immunomarker was negative in 14 ASGSHs (with a positive internal control in AdCC cells), while only two cases showed faint and moderate to weak expression of the antibody in ASGSH glands. In 12 cases, the immunostaining of ASGSH could not be properly assessed, while AdCC cells were negative. The immunostaining was not performed in five cases. Our findings suggest that a subset of sinonasal AdCC may originate in a multistep dysplastic process within SH, consistent with an SH-ASGSH-AdCC progression sequence.

Sinonasal malignancy: ESMO-EURACAN Clinical Practice Guideline for diagnosis, treatment and follow-up

•The CPG provides key recommendations and algorithms for managing SMs, excluding mucosal melanoma and soft-tissue sarcomas. •The guideline covers diagnosis, staging, risk assessment, treatment and disease monitoring. •Technological advancements in treatment with RT are discussed with a special focus on particle therapy. •Surgical indications for open and transnasal endoscopic surgery are provided. •Neoadjuvant chemotherapy in high-grade, locally advanced SMs helps to select subjects for conservative treatments.

[Translocated sinonasal tumors]

In recent years, several nasal cavity and sinus entities have been described with fusion genes. Salivary gland tumors with fusion genes will not be discussed in this article, but it should be kept in mind that accessory salivary glands are present in the nasal cavity and sinuses and can therefore lead to tumoral lesions. Entities with specific or more frequently described rearrangements in the nasal cavities and sinuses are DEK::AFF2 squamous cell carcinomas,;non-intestinal and non-salivary nasosinusal adenocarcinomas, some of which displaying ETV6 gene rearrangements; biphenotypic nasosinusal sarcomas, most of which displaying PAX3 gene rearrangements; and Ewing's adamantinoma-like sarcomas, which display the same rearrangements as conventional Ewing's sarcomas, mainly the EWSR1::FLI1 rearrangement. Each entity will be described morphologically, immunohistochemically, and prognostically.

Sinonasal Adenocarcinomas: An Update

Among sinonasal malignancies, adenocarcinomas account for the second most common entity after squamous cell carcinoma. They span a wide spectrum of neoplasms with heterogeneous features including intestinal-type adenocarcinoma (ITAC), non-intestinal-type adenocarcinomas (non-ITACs), and salivary-type adenocarcinomas. ITAC basically mirrors the histopathological aspects of gastrointestinal counterparts, showing variable tubulo-papillary, colonic, and mixed patterns with mucin production in 20% to 25% of cases. By contrast, non-ITACs do not show any differentiation toward intestinal or salivary phenotype, and they mainly represent a diagnosis of exclusion lacking a proper histopathological and molecular definition.

Sinonasal Hamartomas

A variety of hamartomatous lesions have been described in the sinonasal tract. These include respiratory epithelial adenomatoid hamartoma (REAH), seromucinous hamartoma (SH), and nasal chondromesenchymal hamartoma (NCMH). REAH and SH, demonstrate significant morphologic overlap with each other and with reactive conditions, while also being described to develop in association with other distinct tumors entities. NCMH affects a specific patient population with a specific molecular driver. The hamartomatous/neoplastic nature of REAH and SH are a topic of debate. There are emerging sinonasal hamartomatous entities that appear related to REAH and SH.

Expanding the spectrum of low-grade sinonasal adenocarcinoma with biphasic seromucinous differentiation and activating HRAS/AKT1 mutations

AIMS

Low-grade non-intestinal-type sinonasal adenocarcinoma (LGSNAC) is a rare heterogeneous and poorly characterised group of tumours, distinct from intestinal- and salivary-type neoplasms. Therefore, further characterisation is needed for clearer biological understanding and classification.

METHODS AND RESULTS

Clinical, histological and molecular characterisation of four cases of biphasic, low-grade adenocarcinomas of the sinonasal tract was performed. All patients were male, aged between 48 and 78 years, who presented with polypoid masses in the nasal cavity. Microscopically, virtually all tumours were dominated by tubulo-glandular biphasic patterns, microcystic, focal (micro)papillary, oncocytic or basaloid features. Immunohistochemical staining confirmed biphasic differentiation with an outer layer of myoepithelial cells. Molecular profiling revealed HRAS (p.G13R, p.Q61R) mutations, and concomitant AKT1 (p.E17K, p.Q79R) mutations in two cases. Two cases showed potential in-situ/precursor lesions adjacent to the tumour. Follow-up periods ranged from 1 to 30 months, with one case relapsing locally after 12 and > 20 years.

CONCLUSION

This study further corroborates a distinct biphasic low-grade neoplasm of the sinonasal tract with seromucinous differentiation. Although morphological and molecular features overlap with salivary gland epithelial-myoepithelial carcinoma, several arguments favour categorising these tumours within the spectrum of LGSNAC.

ETV6::NTRK3-associated papillary adenocarcinoma: let us play it by ear

Ceruminous glands are modified apocrine glands, situated in the external auditory canal (EAC) that, together with sebaceous glands, produce cerumen. The neoplastic transformation of these structures is exceedingly rare. We encounter two cases of EAC adenocarcinoma with ETV6::NTRK3 fusion. Despite this genetic overlap, the morphology and immunophenotype delineate its clear separation from secretory carcinoma. These cases demonstrate novel primary EAC adenocarcinoma with papillary morphology, which expands the ever-increasing list of ETV6::NTRK3-positive malignancies and which we would like to term ETV6::NTRK3-translocation associated papillary adenocarcinoma. We also advocate the use of molecular techniques in rare tumors of uncertain type or differentiation, to increase understanding and possibilities of reproducible classification of these rare neoplasms. Pathologists and oncologists should recognize this entity, which leads to a direct approach for detecting NTRK fusion for appropriate treatment.

Update on Sinonasal Tract Malignancies: Advances in Diagnostic Modalities

CONTEXT.—

Sinonasal tract malignancies are rare cancers with frequent morphologic overlap. Given the similar histologic profiles seen in many of these entities, they often present a diagnostic challenge to the practicing pathologist.

OBJECTIVE.—

To provide a streamlined algorithm using histologic clues, immunohistochemical profiles, and molecular assays to aid in diagnosis of these lesions.

DATA SOURCES.—

Sources were the World Health Organization Tumor Classification, literature review, and institutional experience.

CONCLUSIONS.—

Although many sinonasal tract malignancies show similar histology, distinct immunohistochemical and molecular profiles can help parse out differences, thereby facilitating diagnosis for the pathologist.

Non-intestinal-type adenocarcinoma of the nasal cavity and paranasal sinuses: an analysis of clinical characteristics and prognosis

BACKGROUND

Non‑intestinal adenocarcinoma of the nasal cavity and paranasal sinuses (non‑ITAC) is a heterogeneous tumour that has rarely been reported in previous studies. We compared and analysed the symptoms, radiographic and pathological features, treatment methods, and prognosis of patients with low-grade (G1) and high-grade (G3) tumours.

METHODS

This was a retrospective study included 22 patients with pathologically confirmed non-ITAC of the nasal cavity and paranasal sinuses who were treated between January 2008 and December 2021 at a single centre. Of these, 11 patients had G1 tumours, and 11 patients had G3 tumours. Clinicopathological features, treatment methods, and survival outcomes were analysed.

RESULTS

The median follow-up period was 48.5 months. Nasal congestion was the most common initial symptom, and the nasal cavity was the most frequently involved site. For G1 tumours, the main treatment was simple surgery, 1 and 3‑year overall survival (OS) rates were 100 and 88.9%, while the 1 and 3‑year local control (LC) rates were 100 and 100%, respectively. For G3 tumours, the main treatments were surgery combined with radiotherapy and/or chemotherapy,1 and 3‑year OS rates were 72.7 and 72.7%, while the 1 and 3‑year LC rates were 100 and 90.91%, respectively. G3 tumours was associated with significantly shorter overall survival than G1 tumours (P = 0.035). Patients with stage III-IV showed shorter overall survival compared to stage I-II patients (P = 0.035).

CONCLUSIONS

Non-ITAC of the nasal cavity and paranasal sinuses may frequently occur in the nasal cavity. The main treatment modality is surgery, supplemented by radiotherapy and chemotherapy. Pathological grade and tumour stage were poor prognostic factors for the disease.

Nasal and sinonasal tumors formed by atypical adenomatous lesions arising in respiratory epithelial adenomatoid hamartoma/seromucinous hamartoma

Two benign adenomatous lesions are commonly recognized within the sinonasal tract, namely respiratory epithelial adenomatoid hamartoma (REAH) and seromucinous hamartoma (SH). We present 10 hitherto unrecognized benign polypoid nasal and sinonasal tumoriform lesions having in average 3.6 cm in largest dimension, which are histogenetically related to SH and REAH. In addition to typical structures of REAH and SH, these lesions contained an additional characteristic and slightly atypical adenomatous component, which we termed atypical sinonasal glands arising in SH (ASGSH). ASGSH often produced deep red colored secretion with peripheral clearing similar to that seen in thyroid follicles. In contrast to SH, ASGSH was endowed by both secretory and myoepithelial layers and had mostly angulated shapes with snout-like protrusions into the lumens. Both layers were formed by an irregular, disorganized, and often incomplete cell lining, which had slightly atypical cytological features without mitoses. In 3 cases, ASGSHs revealed sebaceous differentiation, and in 3 cases the stroma produced a well-differentiated cartilage. Neoplastic nature of ASGSH was supported by finding of various mutations as revealed by next generation sequencing in five cases. In two cases each, we found identical mutations in BRAF gene (Val600Glu), and RET gene (Arg912Trp), respectively and in one case FAT1 gene alteration (Pro1665Leu).

Genome-wide somatic mutation analysis of sinonasal adenocarcinoma with and without wood dust exposure

BACKGROUND

Sinonasal adenocarcinoma is a rare cancer, encompassing two different entities, the intestinal-type sinonasal adenocarcinoma (ITAC) and the non-intestinal-type sinonasal adenocarcinoma (non-ITAC). Occurrence of ITAC is strongly associated with exposure to hardwood dusts. In countries with predominant exposure to softwood dust the occurrence of sinonasal adenocarcinomas is lower and the relative amount of non-ITACs to ITACs is higher. The molecular mechanisms behind the tumorigenic effects of wood dust remain largely unknown.

METHODS

We carried out whole-genome sequencing of formalin-fixed paraffin-embedded (FFPE) samples of sinonasal adenocarcinomas from ten wood dust-exposed and six non-exposed individuals, with partial tobacco exposure data. Sequences were analyzed for the presence of mutational signatures matching COSMIC database signatures. Driver mutations and CN variant regions were characterized.

RESULTS

Mutation burden was higher in samples of wood dust-exposed patients (p = 0.016). Reactive oxygen species (ROS) damage-related mutational signatures were almost exclusively identified in ITAC subtype samples (p = 0.00055). Tobacco smoke mutational signatures were observed in samples of patients with tobacco exposure or missing information, but not in samples from non-exposed patients. A tetraploidy copy number (CN) signature was enriched in ITAC subtype (p = 0.042). CN variation included recurrent gains in COSMIC Cancer Gene Census genes TERT, SDHA, RAC1, ETV1, PCM1, and MYC. Pathogenic variants were observed most frequently in TP53, NF1, CHD2, BRAF, APC, and LRP1B. Driver mutations and copy number gains did not segregate by subtype.

CONCLUSIONS

Our analysis identified distinct mutational characteristics in ITAC and non-ITAC. Mutational signature analysis may eventually become useful for documentation of occupation-related cancer, while the exact mechanisms behind wood dust-driven carcinogenesis remain elusive. The presence of homologous recombination deficiency signatures implies a novel opportunity for treatment, but further studies are needed.

Challenging differential diagnoses in small biopsies from the sinonasal tract

Sinonasal biopsy specimens are a challenging area in anatomic pathology. The small, often fragmented or crushed nature of these biopsies can hinder morphologic assessment. Additionally, many of the tumors in this area are rare and share morphologic, and sometime immunophenotypic similarities. In many cases, immunohistochemistry is helpful if not necessary to reach a specific diagnosis. In other cases, a specific diagnosis is not possible and a differential diagnosis must be given on a biopsy specimen despite access to a well-equipped immunohistochemistry laboratory. This review article groups some of the more challenging entities in the sinonasal region based on morphologic patterns. These include low grade squamoid lesions such as sinonasal (Schneiderian) papilloma and DEK::AFF2 rearranged carcinoma, glandular neoplasms such as intestinal and non-intestinal type sinonasal adenocarcinoma, high-grade carcinomas such as HPV-related multiphenotypic sinonasal carcinoma, NUT carcinoma and SWI/SNF deficient carcinomas, small round blue cell tumors such as teratocarcinosarcoma, neuroendocrine carcinoma and olfactory neuroblastoma, and finally, low grade spindle cell neoplasms such as glomangiopericytoma, biphenotypic sinonasal sarcoma and solitary fibrous tumor.

High-grade non-intestinal type sinonasal adenocarcinoma with ETV6::NTRK3 fusion, distinct from secretory carcinoma by immunoprofile and morphology

We report 2 cases of high-grade sinonasal adenocarcinoma with a distinct morphological and immunohistochemical phenotype. Albeit histologically different from secretory carcinoma of the salivary glands, both tumors presented here share an ETV6::NTRK3 fusion. The highly cellular tumors were composed of solid and dense cribriform nests, often with comedo-like necroses in the center, and minor areas with papillary, microcystic, and trabecular formations without secretions, mostly located at the periphery of the lesion. The cells displayed high-grade features, with enlarged, crowded, and often vesicular nuclei with conspicuous nucleoli and brisk mitotic activity. The tumor cells were immunonegative for mammaglobin while showing immunopositivity for p40/p63, S100, SOX10, and GATA3, as well as for cytokeratins 7, 18, and 19. For the first time, we describe 2 cases of primary high-grade non-intestinal type adenocarcinomas of the nasal cavity, distinct from secretory carcinoma by morphology and immunoprofile, harboring the ETV6::NTRK3 fusion.

NKX3.1 Expression and Molecular Characterization of Secretory Myoepithelial Carcinoma (SMCA): Advancing the Case for a Salivary Mucous Acinar Phenotype

BACKGROUND

Secretory myoepithelial carcinomas (SMCA) are rare, mucinous, signet ring predominant tumors with primitive myoepithelial features. While many mucinous salivary gland tumors have now been molecularly characterized, key drivers in SMCA have yet to be elucidated. Recently, NKX3.1, a homeodomain transcription factor implicated in salivary mucous acinar development was also shown in a subset of salivary mucinous neoplasms, salivary intraductal papillary mucinous neoplasms (SG-IPMN). To date, NKX3.1 expression has not been characterized in other mucinous salivary lesions. Here, we report molecular and extended immunophenotypic findings in SMCA and NKX3.1 expression in the context of other head and neck lesions.

METHODS

We retrieved 4 previously reported SMCA, performed additional immunohistochemical and targeted next-generation sequencing (NGS). We also investigated the use of NKX3.1 as a marker for SMCA in the context of its prevalence and extent (using H-score) in a mixed cohort of retrospectively and prospectively tested head and neck lesions (n = 223) and non-neoplastic tissues (n = 66).

RESULTS

NKX3.1 positivity was confirmed in normal mucous acini as well as in mucous acinar class of lesions (5/6, mean H-score: 136.7), including mucinous adenocarcinomas (3/4), SG-IPMN (1/1), and microsecretory adenocarcinoma (MSA) (1/1). All SMCA were positive. Fluorescence in situ hybridization for SS18 rearrangements were negative in all successfully tested cases (0/3). NGS was successful in two cases (cases 3 and 4). Case 3 demonstrated a PTEN c.655C>T p.Q219* mutation and a SEC16A::NOTCH1 fusion while case 4 (clinically aggressive) showed a PTEN c.1026+1G>A p.K342 splice site variant, aTP53 c.524G>A p.R175H mutation and a higher tumor mutation burden (29 per Mb). PTEN immunohistochemical loss was confirmed in both cases and a subset of tumor cells showed strong (extreme) staining for P53 in Case 4.

CONCLUSION

Despite a partial myoepithelial phenotype, SMCA, along with mucinous adenocarcinomas/SG-IPMN and MSA, provisionally constitute a mucous acinar class of tumors based on morphology and NKX3.1 expression. Like salivary mucinous adenocarcinomas/SG-IPMN, SMCA also show alterations of the PTEN/PI3K/AKT pathway and may show progressive molecular alterations. We document the first extramammary tumor with a SEC16A::NOTCH1 fusion.

Comprehensive Molecular Profiling of Sinonasal Teratocarcinosarcoma Highlights Recurrent SMARCA4 Inactivation and CTNNB1 Mutations

Sinonasal teratocarcinosarcoma (TCS) is a rare tumor defined by intermixed neuroepithelial, mesenchymal, and epithelial elements. While its etiology was historically ambiguous, we recently reported frequent SMARCA4 loss by immunohistochemistry, suggesting that TCS might be related to SMARCA4-deficient sinonasal carcinomas. However, other molecular alterations including CTNNB1 mutation have been reported in TCS, and its full genetic underpinnings are unclear. Here, we performed the first comprehensive molecular analysis of sinonasal TCS to better understand its pathogenesis and classification. We collected 30 TCS including 22 cases from our initial study. Immunohistochemical loss of SMARCA4 was seen in 22 cases (73%), with total loss in 18 cases (60%). β-catenin showed nuclear localization in 14 cases (64%) of the subset tested. We selected 17 TCS for next-generation sequencing with enrichment for partial or intact SMARCA4 immunoexpression. We identified inactivating SMARCA4 mutations in 11 cases (65%) and activating CTNNB1 mutations in 6 cases (35%), including 5 cases with both. Of 5 cases that lacked SMARCA4 or CTNNB1 mutation, 2 harbored other SWI/SNF complex and Wnt pathway alterations, including 1 with SMARCB1 inactivation and 1 with concomitant APC and ARID1A mutations, and 3 had other findings, including DICER1 hotspot mutation. These findings confirm that SMARCA4 inactivation is the dominant genetic event in sinonasal TCS with frequent simultaneous CTNNB1 mutations. They further underscore a possible relationship between TCS and sinonasal carcinomas with neuroendocrine/neuroectodermal differentiation. However, while SMARCA4 and β-catenin immunohistochemistry may help confirm a challenging diagnosis, TCS should not be regarded as a molecularly defined entity.

Investigation of -PRKACA/-PRKACB fusion genes in oncocytic tumors of the pancreatobiliary and other systems

Intraductal oncocytic papillary neoplasms (IOPNs) of the pancreatobiliary system are tumors comprising oncocytic cells, in which three types of fusion genes involving -PRKACA/-PRKACB were recently identified. IOPNs infrequently combine with other histological subtypes of pancreatic intraductal papillary mucinous neoplasms (IPMNs) and intraductal papillary neoplasms of the bile duct (IPNBs). This study aimed to confirm the sensitivity/specificity of the fusion genes for IOPNs and to examine their significance in other oncocytic lesions. An RT-PCR, followed by DNA sequencing, was undertaken to examine the fusions in 18 histologically diagnosed IOPNs, including four combined IOPNs. Moreover, in two IOPN cases, invasive carcinomatous lesions were separately examined on their fusion status. Oncocytic thyroidal (n = 10), renal (n = 10), and salivary gland (n = 3) lesions and IPMNs (n = 9)/IPNBs (n = 4) with focal oncocytic changes were examined as controls. Fluorescence in situ hybridization using PRKACA break-apart probes was conducted for the combined IOPN cases. Target sequencing of KRAS exon2/3 and GNAS exon 8/9 was performed for IOPN cases. Fusions were detected in all IOPN cases including invasive lesions/none of the control cases. The fusion event was confirmed also in non-IOPN component in one of the four combined cases. Regarding mutation events, 5.6%/0% of IOPNs were KRAS-mt/GNAS-mt, respectively, and both components of combined IOPNs were all KRAS-wt/GNAS-wt. In conclusion, our study confirmed the sensitivity and specificity of these fusions for IOPNs. Here, we analyzed the roles of these fusion genes in combined IOPNs, proposing the possibility of IOPN development via IPMNs/IPNBs. Further studies with more combined cases are warranted.

Sinonasal mixed transitional epithelial-seromucinous papillary glandular neoplasms with BRAF p.V600E mutations - sinonasal analogues to the sialadenoma papilliferum family tumors

Sinonasal non-intestinal type adenocarcinoma (non-ITAC) is a heterogeneous category that may benefit from improved taxonomy. With the recognition that most non-ITAC are phenotypically seromucinous, stratification may be improved by applying salivary type morphologic criteria and molecular findings. We report two cases of papillary seromucinous adenocarcinoma with sinonasal papilloma-like surface components that show histologic and molecular features analogous to the salivary sialadenoma papilliferum family of tumors. Case 1 concerns a 50-year-old female who presented with a left anterior nasoethmoid polyp, while case 2 is that of a 74 year old female with nasal polyposis. Histologically, both cases demonstrated a surface transitional sinonasal papilloma-like component (more prominent in case 2) with a deeper bilayered glandular component showing papillary and tufted micropapillary growth of monomorphic columnar to cuboidal cells with eosinophilic cytoplasm. Case 1 also showed a deep cribriform/microcystic component. Immunostains showed a delimiting p63/p40 positive basal layer around the SOX-10 positive glandular elements, while the transitional sinonasal papilloma-like components were diffusely p63/p40 positive. Like sialadenoma papilliferum and related tumors, both cases demonstrated BRAF p.V600E mutations in both components and no other alterations. The patients remain disease free at 9 and 19 months respectively. Our cases illustrate a novel sinonasal lesion and suggest that improved morphologic and molecular categorization may refine and reduce the category of non-ITAC.

Low-grade tracheal adenocarcinoma with ETV6::NTRK3 fusion: unique morphology akin to subsets of sinonasal low-grade non-intestinal-type adenocarcinoma

The prevalence of NTRK fusions in non-small cell carcinoma (NSCLC) is only approximately 0.2%, most of which harbor NTRK1 fusions. NSCLCs with NTRK3 fusions are extremely rare. Herein, we report a case of low-grade tracheal adenocarcinoma in a 64-year-old woman. Histologically, areas of complicated tubule-papillary or cribriform patterns constituted a major component of the tumor and comprised cuboidal to columnar epithelial tumor cells with pale eosinophilic cytoplasm and cytoplasmic mucin, similar to subsets of sinonasal low-grade non-intestinal-type adenocarcinomas. Immunohistochemically, the tumor was positive for MUC5AC and MUC4 and showed nuclear expression of the pan-Trk antibody. ETV6::NTRK3 was identified by reverse transcription-polymerase chain reaction using formalin-fixed paraffin-embedded tissues. To the best of our knowledge, this is the first case of low-grade tracheal adenocarcinoma with ETV6::NTRK3 fusion. Our case illustrates that low-grade adenocarcinomas with ETV6::NTRK3 fusion may exist throughout the respiratory tract.