Polymorphous Adenocarcinoma Research Articles

Clinicopathological and molecular characteristics of microsecretory adenocarcinoma in salivary gland

Objective: To investigate the clinicopathological, immunohistochemical, and molecular genetic characteristics of microsecretory adenocarcinoma (MSA) of the salivary gland, and to improve the understanding of this rare tumor. Methods: Cases originally diagnosed as MSA at the Department of Oral Pathology, the Ninth People's Hospital of Shanghai Jiao Tong University School of Medicine were retrospectively collected. The cases of polymorphous adenocarcinoma and adenocarcinoma, not otherwise specified from January 2000 to January 2020 were reviewed to identify potential misdiagnosed MSA cases. Clinicopathological analysis and follow-up of all confirmed MSA cases were performed, and relevant literature was reviewed. Results: A total of 4 MSA cases were identified, including 2 screened from the polymorphous adenocarcinoma cohort. Of the 4 MSA patients, 3 were male and 1 was female, with an average age of 53 years (range, 37-67 years). Three cases occurred in the palate, and one in the buccal region. The clinical manifestation was usually a slow-growing painless mass. Tumors were generally small, with a maximum diameter ranging from 0.7 to 1.8 cm (average, 1.2 cm). Microscopically, the tumor was unencapsulated and showed an infiltrative growth pattern. The tumor cells appeared small in size and showed bland, cubic and flattened cytological features, forming microcystic lumens and glandular tubes. Significant basophilic secretions were seen in the lumens. Between the tumor nests there was fibro-myxoid stroma. Immunohistochemistry showed diffusely or partially positive staining for cytokeratin 7, S-100, SOX-10, p63 and vimentin and negative staining for p40, mammaglobin, and calponin. The proliferation index of Ki-67 was relatively low (1%-3%). Four MSA cases all harbored SS18 gene rearrangement as shown by fluorescence in situ hybridization (FISH), including 2 cases with MEF2C::SS18 fusion gene through RNA-targeted next generation sequencing. All 4 patients underwent surgical resection without any adjuvant treatments. Three patients were followed up for a period of 2 to 203 months. No tumor recurrence, metastasis, or disease-related death was found. Conclusions: Salivary gland MSA is a novel and rare low-grade carcinoma with unique and consistent histological morphology, immunophenotype, and molecular changes. Immunohistochemical staining and SS18 break apart FISH are useful for the diagnosis of the tumor with atypical morphology and high-grade transformation.

Perplexing Intraoral Swellings: A Cross-Sectional Study On Minor Malignant Salivary Gland Tumors

Background: This study aims to assess the prevalence and correlation between age, gender, and site of malignant minor salivary gland tumors among patients attending a tertiary healthcare centre in Trivandrum from 2015 to 2022. A total of 26 cases were reviewed, with mucoepidermoid carcinoma (MEC) being the most prevalent, followed by adenoid cystic carcinoma (ACC) and polymorphous adenocarcinoma (PAC). Our findings suggest a slight female predilection overall, though certain tumor types showed gender-specific trends. The study highlights important epidemiological insights that can help future research and clinical practice inmanaging malignant minor salivary gland tumors.

DNA Methylation Profiling of Salivary Gland Tumors Supports and Expands Conventional Classification

Tumors of the major and minor salivary glands histologically encompass a diverse and partly overlapping spectrum of frequent diagnostically challenging neoplasms. Despite recent advances in molecular testing and the identification of tumor-specific mutations or gene fusions, there is an unmet need to identify additional diagnostic biomarkers for entities lacking specific alterations. In this study, we collected a comprehensive cohort of 363 cases encompassing 20 different salivary gland tumor entities and explored the potential of DNA methylation to classify these tumors. We were able to show that most entities show specific epigenetic signatures and present a machine learning algorithm that achieved a mean balanced accuracy of 0.991. Of note, we showed that cribriform adenocarcinoma is epigenetically distinct from classical polymorphous adenocarcinoma, which could support risk stratification of these tumors. Myoepithelioma and pleomorphic adenoma form a uniform epigenetic class, supporting the theory of a single entity with a broad but continuous morphologic spectrum. Furthermore, we identified a histomorphologically heterogeneous but epigenetically distinct class that could represent a novel tumor entity. In conclusion, our study provides a comprehensive resource of the DNA methylation landscape of salivary gland tumors. Our data provide novel insight into disputed entities and show the potential of DNA methylation to identify new tumor classes. Furthermore, in future, our machine learning classifier could support the histopathologic diagnosis of salivary gland tumors.

Diagnostic Dilemma of Palatal Lesions: Polymorphous Adenocarcinoma (PAC) and its Insight into Updated Molecular Findings

Diagnostic Dilemma of Palatal Lesions: Polymorphous Adenocarcinoma (PAC) and its Insight into Updated Molecular Findings

Clinicopathological Features of 26 Intraoral Polymorphous Adenocarcinomas from a Single Brazilian Institution.

This study describes a large, well-documented case series of salivary gland polymorphous adenocarcinomas (PAC) from a single Brazilian center. Demographic data, clinical presentation, histopathological and immunohistochemical features from 26 cases of PAC were analyzed and discussed in detail. Most patients were females (n = 21), with a ratio of 1:4.2 (male: female) with a mean age of 58.8years (ranging from 36 to 84years). The most common clinical presentation was a fibrocollagenous, firm nodular lesion, with a mean size of 2.46cm (ranging from 0.5 to 3cm). Most lesions occurred on the palate (n = 16), followed by buccal mucosa (n = 3), upper lip (n = 3), buccal vestibule (n = 2) and alveolar ridge (n = 1). Histologically, various growth patterns were observed, including tubular, solid, cribriform, papillary, and cystic. Additionally, glomeruloid slit-like structures, mucous, and clear cells were noted. Surface papillary epithelial hyperplasia was observed in a few cases. Nine cases exhibited myxoid and collagenous areas, while two cases showed fusiform areas and another case demonstrated squamous differentiation. Clear cell predominance was noted in two cases, and peri- and intraneural invasion was seen in eight cases. Immunohistochemical analysis revealed positivity for S-100, p63 and CK7, and negativity for p40 in all cases. The Ki-67 proliferation index was markedly low in most cases, with a mean of 2.5%. We have provided a broad, detailed description of the clinical and microscopic features of PAC in a large, Brazilian cohort. These findings, in a resource-limited area, may be quite useful for establishing a proper diagnosis.

A rare case of an aggressive polymorphous adenocarcinoma of minor salivary gland in the retro-maxilla

Abstract Polymorphous adenocarcinoma (PAC) is a low-grade malignant tumour of minor salivary glands of the oral cavity, which rarely presents with invasive features. Low metastatic and excellent survival rates are some of its favorable features. A 36-year-old woman reported with swelling, pain, and mobility of teeth in the left upper inner cheek region. Contrast enhanced computed tomography (CECT) revealed a large, lobulated, heterogenous mass in the left retro-maxillary region with a few enlarged left cervical lymph nodes (levels IB and II). After surgery, the final histopathology report gave a definitive diagnosis of PAC with certain invasive characteristics – perineural invasion, infiltration into skeletal muscle, and depth of invasion of 10 mm, which recurred in a different location 1.5 years later. A few predictable features of PAC include incidence in elderly women, asymptomatic presentation, occurrence in the posterior hard of soft palate, very low incidence of nodal or distant metastases, perineural spread, skeletal muscle infiltration, and low rates of recurrence with good survival outcomes. However, in our case, the patient appeared to present with a relatively aggressive form of PAC, considering her young age, symptomatic presentation, uncommon anatomic location in the retro-maxilla, cervical nodal metastasis, perineural and skeletal muscle infiltration, and local recurrence within a short period. Although PAC is a low-grade tumour with excellent prognosis, it may occasionally present with invasive characteristics, and early diagnosis and prompt management with strict adherence to post-operative regimens and follow-up is of prime importance to prevent any untoward outcomes.

Genetic Rearrangements in Different Salivary Gland Tumors: A Systematic Review.

Salivary gland tumors (SGT) encompass a wide range of neoplasms, each with its own unique histological type and clinical presentation. This review hones in on prevalent subtypes of SGTs, including adenoid cystic carcinoma (ACC), salivary duct carcinoma (SDC), and polymorphous adenocarcinoma (PAC). The articles, identified through specific keywords, were meticulously screened in databases like PubMed, Scopus, Google Scholar, and Web of Science from 2018 to 2023. Eight articles delved into genetic modifications among the selected SGT types. A fusion protein known asMYB-NF1B is typically associated with ACC, promoting cell proliferation while inhibiting apoptosis. The presence of MYB modifications in ACCs is a beacon of hope, as it is linked to a more favorable prognosis. In contrast, SDCs often exhibit HER2 expression. The invasive nature of SGTs contributes to their resistance to treatment. In the case of PAC, the role of PRKD1 is particularly noteworthy. PRKD1, integrated with other genes from the PRKD1/2/3 cluster, helps to differentiate PAC from other diseases. Furthermore, the genetic profiles of KTN1-PRKD1) and PPP2R2A:PRKD1 are distinct. The significant genetic variability among SGTs necessitates meticulous examination. This field is in a constant state of evolution, with new discoveries reshaping our understanding. Genetics is a key player in deciphering SGTs and tailoring treatments. This complex neoplasm demands ongoing research to uncover all genetic influences, thereby enhancing diagnostic methodologies, therapeutic strategies, and patient outcomes.

Oral and oropharyngeal malignant minor salivary gland tumors: A retrospective study

IntroductionTumors of minor salivary gland origin are uncommon lesions, representing 2–3 % of all malignant neoplasms of the upper aerodigestive tract and 9–23 % of all salivary gland tumors.The aim of this study is to report the demographic features, sites, histological types and the management and outcomes of oral and oropharyngeal minor salivary gland tumors diagnosed and treated in a University Hospital with a multidisciplinary head and neck team. Materials and methodsA single-center retrospective observational study was conducted in a cohort of patients who received diagnosis of minor salivary gland carcinoma of oropharynx and oral cavity between July 30th 2000 and 30th September 2021. The following data of the included patients were collected: age, gender, smoke history, alcohol consumption, past medical history, comorbidities, anatomic location of the tumor, histopathology, staging, management, and outcomes. ResultsA total of 30 cases (16 females, 14 males) of oral and oropharyngeal minor salivary gland tumors were reviewed. The most frequent histotype was polymorphous adenocarcinoma (12 patients). The majority of patients presented with low stage at diagnosis, with 66,66 % of the population classified as stage I or II at diagnosis. On the whole, 29 patients out of 30 benefitted from a surgical approach as first treatment. In 11 patients, adjuvant radiotherapy was performed and in 6 cases it was associated with chemotherapy. Brachytherapy with different timing was performed in 5 cases. The recurrence rate was 26.66 %. Overall disease specific survival at five and ten years was found to be approximately 81 % and 33 % respectively. ConclusionsSurgery is still considered to be the gold standard of the treatment of minor salivary gland tumors. Radiation therapy, in spite of not being considered as a curative primary treatment for salivary malignancies, is extensively used as an adjuvant treatment.

Salivary gland-type cancers: cross-organ demographics of a rare cancer.

Salivary gland-type cancers (SGTCs) are histologically heterogeneous and can affect organs other than the salivary glands. Some tumors outside the salivary glands are diagnosed on their unique histological characteristics. Comprehensive cross-organ studies on SGTCs are limited. We retrospectively analyzed the data of patients with salivary duct carcinoma (SDC), adenoid cystic carcinoma (AdCC), mucoepidermoid carcinoma (MEC), epithelial-myoepithelial carcinoma (EMC), acinic cell carcinoma (AcCC), and polymorphous adenocarcinoma (PAC) who visited our institution between 2009 and 2019. The primary tumor sites were classified into four categories; major salivary glands, head/neck (H/N) excluding (exc) major salivary glands (MSG) regions, broncho-pulmonary regions, and "others". H/N exc MSG was further divided into three subcategories, nasal/paranasal sinus, oral and pharynx/larynx. We identified 173 patients with SGTCs, with SDC, AdCC, MEC, EMC, AcCC, and PAC accounting for 20%, 42%, 27%, 3%, 8%, and 1% of the cases, respectively. The most frequent primary site was the major salivary glands (64%), followed by H/N exc MSG regions (27%), broncho-pulmonary regions, and "others", thus non-salivary gland origins accounted for 9% of all cases. Patients with SDC, MEC, AcCC, or SGTC of the major salivary glands and broncho-pulmonary regions were more frequently treated by surgery. The overall survival time of the patients with MEC was significantly better than that of patients with SDC or EMC. This cross-organ study highlights the clinical significance of SGTCs, underscoring the need for developing novel therapies for this rare disease entity.

Expression of FOXI1 and POU2F3 varies among different salivary gland neoplasms and is higher in Warthin tumor

PurposeSalivary gland tumors are histologically diverse. Ionocytes and tuft cells, rare epithelial cells found in normal salivary glands, might be associated with salivary tumors. Here, we explored the expression of FOXI1 and POU2F3, master regulators of ionocytes and tuft cells, respectively, for common salivary neoplasms using immunohistochemistry.MethodsWe analyzed normal salivary tissues and nine salivary gland tumors; Warthin tumors (WT), pleomorphic adenomas (PA), basal cell adenomas, and oncocytomas were benign, whereas mucoepidermoid, adenoid cystic, acinic cell, salivary duct carcinomas, and polymorphous adenocarcinomas were malignant.ResultsNormal salivary glands contained a few FOXI1- and POU2F3-positive cells in the ducts instead of the acini, consistent with ionocytes and tuft cells, respectively. Among the benign tumors, only WTs and PAs consistently expressed FOXI1 (10/10 and 9/10, respectively). The median H-score of WTs was significantly higher than that of PAs (17.5 vs. 4, P = 0.01). While WTs and PAs harbored POU2F3-positive cells (10/10 and 9/10, respectively), the median H-score was higher in WTs than in PAs (10.5 vs 4, respectively). Furthermore, WTs exhibited a unique staining pattern of FOXI1- and POU2F3-positive cells, which were present in luminal and abluminal locations, respectively. Whereas none of the malignant tumors expressed FOXI1, only adenoid cystic carcinoma consistently expressed POU2F3 (5/5), with a median H-score of 4.ConclusionThe expression patterns of the characteristic transcription factors found in ionocytes and tuft cells vary among salivary gland tumor types and are higher in WT, which might be relevant for understanding and diagnosing salivary gland neoplasms.

Polymorphous Adenocarcinoma: A Systematic Review of the Literature and Presentation of Two Cases in a Less-Considered Anatomical Site.

Polymorphous adenocarcinoma (PAC) is the second-most common malignant tumour of the minor salivary glands. Although PAC predominantly affects the palate, it can also involve the buccal mucosa. This systematic review aims to investigate the literature data about PAC. Furthermore, we report two cases of patients affected by PAC in an infrequently considered anatomical site. According to PRISMA guidelines, a systematic review search was conducted on PubMed, Scopus, and Web of Science. Observational studies conducted on patients with a histological diagnosis of PAC were selected and analysed. Furthermore, two cases of patients with PAC affecting the buccal mucosa were reported. Twenty-nine studies were included, and 143 patients affected by PAC were analysed (62 males, 75 females, and 6 undefined, with a mean age of 57.4 ± 14.5 years). The palate was the most affected site (99/143, 69.2%), followed by the buccal mucosa (12/143, 8.4%). Moreover, we report two cases of patients with PAC affecting the buccal mucosa (one male and one female, with a mean age of 70.5 ± 2.5 years). The present study underscores the importance of considering the buccal mucosa as a possible location of minor salivary gland tumours; although it is a less-considered affliction, it is not uncommon.

BubR1 and cyclin B1 immunoexpression in pleomorphic adenoma and polymorphous adenocarcinoma of minor salivary glands

The immunoexpression of BubR1 and cyclin B1 in pleomorphic adenoma (PA) and polymorphic adenocarcinoma (PAC) in minor salivary glands is poorly studied. Thus, a retrospective and observational study was performed to provide a better understanding of the role and immunopositivity patterns of these proteins in these lesions. Sixteen cases of PA and 16 cases of PAC were selected. Parenchyma cells were submitted to quantitative immunohistochemical analysis through the labeling index. Cytoplasmic immunoexpression of BubR1 was observed in neoplastic cells from all analyzed PA and PAC cases. All PA cases and 93.7% of PAC exhibited nuclear immunoexpression of BubR1. Higher cytoplasmic and nuclear immunoexpression of BubR1 was observed in PAC (p = 0.001 and p = 0.122, respectively). Cytoplasmic immunoexpression of cyclin B1 was observed in all cases of PA and PAC, with a higher labeling index in the latter (p < 0.001). There was a significant positive correlation between nuclear and cytoplasmic BubR1 immunoexpressions (p < 0.001) in PA and a significant negative correlation between BubR1 and cyclin B1 cytoplasmic immunoexpressions (p = 0.014) in PAC. The higher cytoplasmic and nuclear immunoexpression of BubR1 in PACs suggests the continuous maintenance of neoplastic cells in the cell cycle and migration. Higher immunoexpression of cyclin B1 supports this lesion's enhanced proliferative and migration ability.

Utility of MUC4 in the diagnosis of secretory carcinoma of salivary glands

Salivary gland tumors are diverse in morphology and both benign and malignant tumors may pose diagnostic challenges especially in small biopsies. Secretory carcinoma (SC) is histologically characterized by microcysts, follicles, solid growth pattern and occasional papillary structures, and absence of zymogen granules. SC is molecularly defined by the presence of novel gene fusion ETV6::NTRK3. Among the positive stains (S100 and mammaglobin), MUC4 is now another promising marker for the diagnosis of SC, that would enable the pathologists to exclude other morphologically close simulators. Aim of this study was to report clinicopathological features and assess utility of MUC4 in the diagnosis of SC. MUC4 was performed on 22 cases of SC. Glass slides were reviewed to record morphological patterns and staining of S100, mammaglobin, DOG1 and MUC4. Age ranged from 9 to 63 years with mean age of 34.41 ± 16.28 years. The male: female ratio was 72.7 %:27.3 %. The majority occurred in major salivary glands. A combination of patterns was seen; microfollicles were the most prevalent (90 %) followed by papillary-cystic and macrofollicles. MUC4 was positive in 19/21 (90 %) cases with almost equal number of 2+ and 3+ staining. MUC4 was negative in all cases of acinic cell carcinoma, polymorphous adenocarcinoma, adenoid cystic carcinoma, salivary duct carcinoma, myopepithelioma and myoeithelial carcinoma, cystadenoma and cribriform adenocarcinoma and all except 3 cases of mucoepidermoid carcinoma tested. Overall sensitivity of MUC4 was 95.4 %, specificity 90 %, p-value being <0.01, positive predictive value 87.5 % and negative predictive value 96.4 %. A characteristic cytoplasmic granular pattern was observed in 76.1 % tumors. S100 and mammaglobin were positive in all the performed cases. DOG1 was positive in 6/11 (28.5 %) tumors. In conclusion, MUC4 is a useful addition to a diagnostic immunohistochemical panel for SC, and to distinguish it from close potential mimickers such as acinic cell carcinoma, especially in practice settings where molecular testing is unavailable.

Recent developments in the pathology of primary pulmonary salivary gland-type tumours.

Primary pulmonary salivary gland-type tumours are rare neoplasms that are thought to arise from seromucinous glands that are located in the submucosa of large airways. These neoplasms have clinical and pathologic features that are distinct from other pulmonary neoplasms. The majority of primary pulmonary salivary gland-type tumours are malignant, with the most common entities being mucoepidermoid carcinoma, adenoid cystic carcinoma, and epithelial-myoepithelial carcinoma. Less commonly seen are myoepithelial carcinoma, hyalinizing clear cell carcinoma, acinic cell carcinoma, secretory carcinoma, salivary duct carcinoma, intraductal carcinoma, and polymorphous adenocarcinoma. Benign salivary gland-type tumours of the lung include pleomorphic adenoma and sialadenoma papilliferum. Morphologic, immunophenotypic, and molecular features of these neoplasms are largely similar to salivary gland tumours elsewhere, and therefore the exclusion of metastatic disease requires clinical and radiologic correlation. However, the differential diagnostic considerations are different in the lung. The distinction of salivary gland-type tumours from their histologic mimics is important for both prognostication and treatment decisions. Overall, salivary gland type-tumours tend to have a more favourable outcome than other pulmonary carcinomas, although high-grade variants exist for many of these tumour types. Recent advances in our understanding of the spectrum of salivary gland-type tumours reported in the lung and their diversity of molecular and immunohistochemical features have helped to refine the classification of these tumours and have highlighted a few differences between salivary gland-type tumours of the lung and those primary to other sites.

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.

TRPS1 immunohistochemical expression in salivary gland tumors: A pilot study.

TRPS1 is a new, sensitive marker for breast carcinoma (BC). Salivary glands and breasts are both exocrine glands; thus, their tumors may share similar morphology and immunophenotype. Among salivary gland-type BC, TRPS1 is reported to be positive in secretory carcinomas (SCs) but negative in acinic cell carcinomas (AciCCs) and most adenoid cystic carcinomas (AdCCs). A subset of salivary duct carcinomas (SDCs) is positive for TRPS1. Herein, we investigate TRPS1 immunohistochemical expression in salivary gland tumors (SGTs). A retrospective search yielded 110 SGTs (97 primary and 13 metastatic). TRPS1 immunohistochemistry was scored as negative, low positive, intermediate positive, or strongly positive. TRPS1 was expressed in 78% (14/18) of pleomorphic adenoma (PA) cases but negative/low positive in all Warthin tumors (6/6 [100%]). In basal cell adenoma (BCA), TRPS1 expression was intermediate to strong (13/14 [92%]) in the stromal cells, whereas ductal or basal cells showed low expression. TRPS1 expression varied in malignant SGTs, with intermediate to strong staining in 100% (15/15) of AdCCs, 100% (5/5) of basal cell adenocarcinoma, 100% (3/3) of intraductal carcinoma, 89% (8/9) of polymorphous adenocarcinoma, and 89% (7/8) of SDCs; negative/low positive expression was observed in 100% (3/3) of SCs, 89% (8/9) of AciCCs, and 50% (3/3) of mucoepidermoid carcinomas. In addition, strong and intermediate TRPS1 expression was observed in metastatic SGT to the lungs, lymph nodes, and soft tissue. Overall, TRPS1 is strongly expressed in PA as well as malignant and metastatic SGT. In addition, TRPS1 is positive in stromal cells of BCA but negative or low positive in ductal and basal cells.

Stereotactic radiosurgery for recurrent skull base polymorphous adenocarcinoma invading the cavernous sinus: illustrative case.

Polymorphous adenocarcinomas (PACs) are rare tumors arising from the salivary glands. Radical resection and postoperative radiotherapy are the mainstays of treatment. However, complete tumor resection is not always achievable when the tumor invades the skull base. Stereotactic radiosurgery (SRS) could be a less invasive alternative for treating skull base PACs. A 70-year-old male with a history of surgery for a right palatine PAC presented with right visual impairment, diplopia, and ptosis. Imaging studies revealed tumor recurrence invading the right cavernous sinus (CS). SRS using a gamma knife was performed for this recurrence, prescribing a marginal dose of 18 Gy at a 50% isodose line. Five months after SRS, his symptoms were relieved, and the tumor was well-controlled for 55 months without any adverse events. To the best of the authors' knowledge, this is the world's first case of recurrent skull base PAC invading the CS that was successfully treated with salvage SRS. Thus, SRS may be an applicable treatment option for skull base PACs.

Polymorphous adenocarcinoma of the buccal space—Rare, reported case from our institute

ABSTRACT Polymorphous adenocarcinoma (PAC) of head and neck tumors is a rare salivary gland neoplasm of indolent course. We reported a 63-year-old female who presented as an asymptomatic mass in buccal space. The patient, after metastatic workup, underwent complete excision of the lesion with a negative margin. Postoperative histopathology and immunohistochemistry (IHC) were suggestive of PAC. Presently patient is on follow-up as per a multidisciplinary team decision. To conclude, PAC diagnosis is challenging due to morphological diversity, which necessities IHC. In addition, presently treatment of choice as per the literature review is complete excision.

Immunoexpression of Autophagy-Related Proteins in Salivary Gland Tumors: An Exploratory Study.

Autophagy is a cellular survival mechanism involved in several human diseases, but its participation in the development of salivary gland tumors is not fully understood. This study investigated the immunoexpression of autophagy-related proteins (autophagy-related 7 [Atg7], microtubule-associated protein 1 light chain 3A [LC3A], microtubule-associated protein 1 light chain 3B [LC3B], protein p62 [p62], and phosphorylated mammalian target of rapamycin [p-mTOR]) in pleomorphic adenoma (PA), polymorphous adenocarcinoma (PAC), mucoepidermoid carcinoma (MEC), and adenoid cystic carcinoma (ACC) of salivary glands. Twenty PAs, 20 PACs, 20 MECs, and 14 ACCs were selected. The percentages of cytoplasmic and nuclear positivity for autophagy-related proteins in neoplastic cells were assessed and correlated with histopathological parameters. Cytoplasmic immunoexpression of Atg7 was observed in all groups, with high median percentages of positivity. Regarding LC3A and LC3B, cytoplasmic immunoexpression was found in most PACs (95%) and in all cases of PA, MEC and ACC, with the highest percentages of positivity in PACs and PAs (p < 0.005). ACCs exhibited lower cytoplasmic immunoexpression of p-mTOR (p < 0.005) and lower nuclear expression of p62 (p < 0.05) when compared to PAs, PACs and MECs. Low nuclear immunoexpression of Atg7, LC3A and p-mTOR and absence of nuclear staining for LC3B were observed in all groups. Regarding histopathological parameters of PAs, MECs and ACCs, there were no significant differences in the expression of autophagy-related proteins. In all groups, positive correlations were observed between the immunoexpression of some autophagy-related proteins (p < 0.05). The results suggest the participation of autophagy in the pathogenesis of PA, PAC, MEC, and ACC of salivary glands. Upregulation of autophagy and reduced nuclear translocation of p62 may contribute to the aggressive biological behavior of salivary gland ACC.

Cribriform adenocarcinoma of the minor salivary glands: a case report

BackgroundPolymorphous adenocarcinoma is the third most common malignant salivary gland tumor. Within polymorphous adenocarcinoma, cribriform adenocarcinoma of salivary glands is a rare subtype and resembles papillary thyroid carcinoma histopathologically. Diagnostically, cribriform adenocarcinoma of salivary glands is challenging for pathologists and surgeons alike as initial presentation and cytologic nuclear features can be easily confused with papillary thyroid carcinoma arising from a thyroglossal duct remnant or lingual thyroid.Case presentationA healthy 64-year-old Caucasian woman presented to a community otolaryngologist with a 4-year history of progressive postnasal drip, globus sensation, and eventual dysphonia. Flexible fiberoptic laryngoscopy showed a large, smooth, vallecular lesion filling the oropharynx. Computed tomography imaging of the neck showed a rounded heterogeneous mass centered within the right aspect of the oropharynx measuring 4.2 × 4.4 × 4.5 cm. Fine needle aspiration biopsy was suspicious for papillary carcinoma due to microscopic findings of malignant cells, nuclear grooves, and a powdery chromatin pattern. In the operating room, the tumor was resected en bloc using a lateral pharyngotomy approach with partial resection of the right lateral hyoid. A limited cervical lymphadenectomy was performed to facilitate the lateral pharyngotomy approach and two out of three lymph nodes demonstrated regional metastatic disease. Nuclear grooves, nuclear membrane notching, and occasional intranuclear pseudoinclusions were identified, which are overlapping histopathological characteristics of papillary thyroid carcinoma and cribriform adenocarcinoma of salivary glands. It was negative for thyroglobulin and thyroid transcription factor-1, which was in keeping with cribriform adenocarcinoma of salivary glands rather than papillary thyroid carcinoma.ConclusionIt is difficult to distinguish cribriform adenocarcinoma of salivary glands from papillary thyroid carcinoma solely by cytology, and the distinct characteristics of regional lymph node metastasis coupled with nuanced histologic differences should be emphasized in the evaluation of patients presenting with neck lymphadenopathy and an unknown primary or tongue mass. If sufficient fine needle aspiration biopsy material is available, thyroid transcription factor-1, thyroglobulin, or molecular testing may prove useful in differentiating cribriform adenocarcinoma of salivary glands from papillary thyroid carcinoma. A misdiagnosis of papillary thyroid carcinoma may lead to inappropriate treatment including unnecessary thyroidectomy. Therefore, it is critical for both pathologists and surgeons to be aware of this uncommon entity to avoid misdiagnosis and subsequent mismanagement.