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Background:
We evaluated the diagnostic accuracy (DA), risk of neoplasm (RON), and risk of malignancy (ROM) for the commonly encountered malignant salivary gland tumors mucoepidermoid carcinoma (MECa), acinic cell carcinoma (ACCa), and adenoid cystic carcinoma (ADCa) applying The Milan System for Reporting Salivary Gland Cytology (MSRSGC).
Materi...
Context in source publication
Context 1
... differentiating between a non-neoplastic, benign, and/or malignant salivary gland lesions is not always feasible in FNA specimens due to morphologic overlap, tumor heterogeneity, metaplastic changes (commonly encountered in non-neoplastic lesions), and sampling issues. 6 Mucoepidermoid carcinoma (MECa), (Fig. 1), acinic cell carcinoma (ACCa), (Fig. 2), and adenoid cystic carcinoma (ADCa), (Fig. 3), are the most common malignant salivary gland neoplasms. These malignant neoplasms share cytomorphologic features with other benign and malignant salivary gland neoplasms and even with nonneoplastic lesions. Therefore, only a fraction of these commonly encountered malignant neoplasms is ...
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Purpose: Salivary gland cancer (SGC) in the oral cavity is not common and has been less studied in comparison with oral squamous cell carcinoma (SCC). This study aimed to identify the clinical characteristics and outcomes of SGC in the oral cavity compared with oral SCC.
Methods: The medical charts of the patients with SGC (N = 68) arising from min...
Citations
... Cytomorphologically, ADCa exhibits distinct characteristic features. These include monotonous cells characterized by round, hyperchromatic nuclei, which surround spherical hyaline matrix material [34][35][36], shown in Figures 3A-3C. The cells are organized in sheets, clusters, or tubules, sometimes accompanied by naked nuclei in the background [34][35][36]. ...
... These include monotonous cells characterized by round, hyperchromatic nuclei, which surround spherical hyaline matrix material [34][35][36], shown in Figures 3A-3C. The cells are organized in sheets, clusters, or tubules, sometimes accompanied by naked nuclei in the background [34][35][36]. Hyaline globules are variable in size and they are usually larger than hyaline globules that can be seen in PA. Hyaline globules are dense, homogenous, round or tubular shape with sharp outlines, which appear magenta on Diff-Quik and green-gray in Papanicolaou stain. ...
... Hyaline globules are dense, homogenous, round or tubular shape with sharp outlines, which appear magenta on Diff-Quik and green-gray in Papanicolaou stain. Differential diagnosis for ADCa encompasses several benign entities, such as PA, basal cell adenoma, myoepithelioma, lymphadenoma, and cystadenoma [17, 28,34,36,37]. Basal cell adenoma is characterized by large fragments of cohesive basaloid cells surrounded by a rim of basement like matrix such as Figure 3D. It is important to be aware that these benign entities might exhibit high nuclear-to-cytoplasmic ratios and matrix material on cytological examination, potentially leading to overdiagnosis. ...
Background: Salivary gland lesions possess diagnostic challenges on fine needle aspiration (FNA) material. They are relatively uncommon, yet present with a wide spectrum of cytomorphology. Herein, we review common salivary gland neoplasms, their cytomorphologic features, their diagnostic pitfalls, and ancillary studies helpful in achieving an accurate diagnosis. Summary: There are many cytomorphologic overlaps between benign and malignant salivary gland entities. Moreover, metaplasia, cystic changes, and degenerative changes are common findings adding to diagnostic dilemmas. These complicating factors contribute to a minute risk of malignancy in salivary gland lesions that are interpreted as benign on FNA. In rare cases, even malignant salivary gland neoplasms are misinterpreted as benign on aspirated material due to the many cytomorphologic overlaps. For example, benign and malignant neoplasms containing stroma such as myoepithelioma and adenoid cystic carcinoma may be misinterpreted as pleomorphic adenoma. Moreover, diagnosis of salivary gland neoplasms with basal cell features can be confusing on FNA materials; for example, basal cell adenoma can be misinterpreted as adenoid cystic carcinoma. Mucoepidermoid carcinomas have many different appearances on aspirated material due to variable amounts of mucin, degree of nuclear atypia, cellular content, and squamous metaplasia. Acinic cell carcinoma exhibits large cells with abundant cytoplasm on FNA, which can be mistaken for oncocytic cells in oncocytoma or Warthin tumor. Salivary duct carcinoma shows distinct features of malignancy and thus can be mistaken for secondary tumors involving the salivary glands or other malignant salivary gland tumors. The presence of tumor-associated lymphocytes is another underlying cause of misdiagnosis, especially when considering the differential diagnosis of an an intraparotid lymph node. Ancillary studies such as immunohistochemistry and molecular studies are gaining more attention to be utilized on FNA cases. PLAG1 immunostaining, CD117 , DOG1, mammaglobin, and androgen receptor (AR) are examples of commonly used immunostains in diagnosis of salivary gland lesions. MYB gene fusion , rearrangements of the MAML2 gene, ,and ERBB2/HER2 are examples of molecular alterations useful in diagnosis of salivary gland neoplasms. In conclusion, the aim of salivary gland cytology is to differentiate benign entities from the malignant ones and to prevent unnecessary aggressive treatments.
... While approximately half of AdCC, AciCC, SC, and MEC cases are diagnosed as malignant by cytomorphology alone (46%) (Figure 2, E), many of these cases are diagnosed as SUMP (43%) or SUS (11%). 52 In a study from the Memorial Sloan Kettering Cancer Center, 33.3% of AciCC and 50% of AdCC cases were in a SUMP category. 23 Based on their specific genetic alterations and/or immunoprofiles, 2 ancillary studies can readily confirm the diagnosis for these entities, allowing them to be placed in a definitive malignant category ( Figure 3). ...
Context.—:
Fine-needle aspiration (FNA) is a well-established procedure for the diagnosis and management of salivary gland lesions, despite challenges imposed by salivary gland tumor diversity, complexity, and cytomorphologic overlap. Until recently, the reporting of salivary gland FNA specimens was inconsistent among different institutions throughout the world, leading to diagnostic confusion among pathologists and clinicians. In 2015, an international group of pathologists initiated the development of an evidence-based tiered classification system for reporting salivary gland FNA specimens, the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC). The MSRSGC consists of 6 diagnostic categories, which incorporate the morphologic heterogeneity and overlap among various nonneoplastic, benign, and malignant lesions of the salivary glands. In addition, each MSRSGC diagnostic category is associated with a risk of malignancy and management recommendations.
Objective.—:
To review the current status of salivary gland FNA, core needle biopsies, ancillary studies, and the beneficial role of the MSRSGC in providing a framework for reporting salivary gland lesions and guiding clinical management.
Data sources.—:
Literature review and personal institutional experience.
Conclusions.—:
The main goal of the MSRSGC is to improve communication between cytopathologists and treating clinicians, while also facilitating cytologic-histologic correlation, quality improvement, and research. Since its implementation, the MSRSGC has gained international acceptance as a tool to improve reporting standards and consistency in this complex diagnostic area, and it has been endorsed by the 2021 American Society of Clinical Oncology management guidelines for salivary gland cancer. The large amount of data from published studies using MSRSGC served as a basis for the recent update of the MSRSGC.
... Similar to our study design, Shafique et al. 10 10 The reason given as to why only 40% of their HG MEC aspirates (in contrast to our 97%) were diagnosed as M/SM was due to the lack of lesional cells in the cytologic sample. A large (111 cases) multi-institutional international study of MEC showed that 57% of all diagnoses could be grouped into the critical M/SM categories using MSRSGC; 19 this is much less when compared with the 76% M/SM categorization of all diagnoses from our case series. Although the FN rate was 0 from that study, 4 of 63 (6%) M/SM diagnoses were false-positives, and a much higher percentage of cases (43%) were grouped into the SUMP class compared with our overall 9% SUMP diagnoses. ...
... Although the FN rate was 0 from that study, 4 of 63 (6%) M/SM diagnoses were false-positives, and a much higher percentage of cases (43%) were grouped into the SUMP class compared with our overall 9% SUMP diagnoses. 19 This distinction is clinically relevant because a SUMP diagnosis where the stated risk of malignancy (ROM) is listed as 35% 12 (although slightly higher at 41% for submandibular gland tumors 20 ), does not necessarily convey the same immediacy as a M or SM diagnosis (stated ROM of 60 and 90%, respectively). 12 Even though the Milan recommendation for a SUMP interpretation is surgery, the clinician is usually unaware of the implication of a SUMP diagnosis. ...
... Many other reports have mistaken MEC and PA with one another including those cases undergoing cystic degeneration and containing sebaceous cells imitating mucocytes. 5,19,25,[29][30][31][32][33] Klijanienko et al. 34 reported the presence of chondromyxoid stroma in the rare instance of MEC ex PA. As illustrated in Figures 7D and 7E, mucus in MEC may very infrequently imitate the fibrillar quality of PA matrix in R-stained smears. ...
Background
Mucoepidermoid carcinoma (MEC) is the most common salivary gland (SG) malignancy. In this study, the author undertook analysis of a large collection of MEC cytologic cases.
Materials and Methods
Cytopathology files were searched for MEC cases with histopathologic confirmation. Fine‐needle aspiration (FNA) smears used standard technique.
Results
Seventy‐six cases (63 patients [M:F = 1:1; age range, 23–87 years; mean age, 58 years]) met inclusion criteria. Aspirates were primary (54 [71%]), metastatic (18 [24%]), and locally recurrent (4 [5%]). FNA sites included parotid gland (49 [64%]), regional lymph nodes (11 [14%]), submandibular gland (5 [7%]), inner canthus of eye (2 [3%]), and lung (2 [3%]); and single specimens from palate, jaw, shoulder, paranasal sinus, floor of mouth, ear canal, and effusion. Cytologic diagnoses included MEC (30 cases [39%]), suspicious for MEC (16 [21%]), non‐MEC carcinoma (9 [12%]), suspicious for malignancy (SM) (2 [3%], malignant (M) (1 [1%]), SG and/or suspicious SG neoplasm (7 [8%]), atypical (3 [5%]), nonneoplastic (5 [6%]), nondiagnostic (2 [3%]), and benign SG neoplasm (1 [1%]). A total of 26% of low‐grade (LG) cases were diagnosed as malignant in contrast to 87% malignant in high‐grade (HG) cases. Cytomorphology depended on tumor grade. LG MEC contained intra‐ and/or extra‐cellular mucin and more uniform cell and/or nuclear morphology, whereas cytologic atypia, anisonucleosis, and keratotic cells were more typical of HG tumors.
Conclusion
A malignant (M) or suspicious for malignancy (SM) cytologic interpretation was made in 76% of mucoepidermoid carcinoma (MEC) cases. In contrast to high‐grade MEC (97% identified as M/SM), only 59% of low‐grade (LG) MEC cases were interpreted as such, illustrating the continued diagnostic challenge posed by LG MEC using fine‐needle aspiration biopsy.
... In typical cases, the FNA diagnosis of the previously mentioned tumors is usually straightforward. 11,[24][25][26][27] Occasional cases lacking classic cytomorphologic features, particularly those with superimposed reactive or metaplastic changes, would be placed in SUMP under this subcategory. Lubin et al demonstrated a high ROM in oncocytoid neoplasms with mucinous background (83.0%) and a low ROM in cases with cystic background (6.3%). ...
BACKGROUND
The salivary gland neoplasm of uncertain malignant potential (SUMP) category in the Milan System is diagnostically challenging. This study aims to validate a modified scheme for subcategorizing SUMP in a large multi‐institutional cohort.
METHODS
Retrospective review of salivary gland fine‐needle aspirations (FNAs) from 10 institutions were classified based on the Milan System. Cases diagnosed as SUMP with available cytology slides and surgical follow‐up were retrieved for review and subcategorized based on a modified scheme as follows: basaloid SUMP (B1: absent/scant nonfibrillary matrix; B2: presence of nonfibrillary/mixed‐type matrix), oncocytic/oncocytoid SUMP (O1: with mucinous background; O2: without mucinous background), and SUMP not otherwise specified (NOS).
RESULTS
A total of 742 (7.5%) cases from 9938 consecutive salivary gland FNAs were classified as SUMP. Among them, 525 (70.8%) had surgical follow‐up and 329 (62.7%) were available for review. The overall risk of malignancy (ROM) of SUMP was 40.4%. There were 156 cases (47.4%) subcategorized as basaloid SUMP with a ROM of 36.5%, 101 (30.7%) as oncocytic/oncocytoid SUMP with a ROM of 52.5%, and 72 (21.9%) as SUMP NOS with a ROM of 31.9%. The ROM of oncocytic/oncocytoid SUMP was significantly higher than basaloid SUMP (P = .0142) and SUMP NOS (P = .0084). No significant differences in ROM were noted between B1 and B2 (36.7% vs 36.4%, P = 1.0000) and O1 and O2 (65.2% vs 48.7%, P = .2349).
CONCLUSIONS
The ROM of oncocytic/oncocytoid SUMP was 52.5% and significantly higher than that of basaloid SUMP (36.5%, P = .0142) and SUMP NOS (31.9%, P = .0084), whereas no significant differences in ROM were noted for cases with different types of extracellular matrix or background material.;
... Institutional Review Board approval for a retrospective search of the electronic health records for cases of SC of the salivary gland was obtained from 12 The pathology information systems of these 12 academic institutions were searched for cases of SC that had undergone FNA biopsy during the workup. For search query purposes, both secretory carcinoma and mammary analogue secretory carcinoma were included to account for changes in diagnostic terminology over time. ...
... The tumor with no detectable fusion (1 of 33 cases; 3%) was from a man aged 47 years with a confirmed history of SC of the cheek who presented with a supraclavicular metastasis on which the negative FISH study was performed on FNA material. Molecular genetic testing results for ETV6 rearrangement are summarized in Table 3. (27) Large-to-medium size (28) Round-to-oval (32) Moderate-to-abundant (29) Abundant mucin (8) Crowding (27) Micropapillae and thin papillae (13) Round-to polygonal (28) Eccentric (18) Vacuolated including large and small vacuoles (23) Bubbly secretions (2) Single cells (12) Epithelioid (5) Central (14) Finely granular (11) Granular with amorphous proteinaceous debris (9) Transgressing vessels (2) Clear cell (2) Smooth contour ...
... Other cystic cases may be definitively identified by molecular testing if sufficient cellularity is present. 12 High-grade features were reliably absent from FNA smears of SC, although high-grade transformation of SC is known as a rare phenomenon. 13,14 Mitotic activity was reported to be prevalent in SC in 1 study; however, only rare mitotic activities were observed in our study. ...
BACKGROUND
Secretory carcinoma (SC) of the salivary gland is a rare entity with limited published literature on cytomorphology. The authors present the largest cohort to date of SC fine‐needle aspiration (FNA) cases.
METHODS
FNA cases of histologically confirmed SC were retrospectively retrieved from 12 academic institutions in the United States, Italy, Finland, and Brazil. The collated data included patient demographics, imaging findings, cytopathologic diagnoses according to the Milan System for Reporting Salivary Gland Cytopathology, cytomorphologic characteristics, and immunohistochemical/molecular profiles.
RESULTS
In total, 40 SCs were identified (male‐to‐female ratio, 14:26) in patients with a mean age of 52 years (age range, 13‐80 years). Ultrasound imagining revealed a hypoechoic, ovoid, poorly defined, or lobulated mass. The most common primary site was the parotid gland (30 of 40 tumors). Regional lymph node metastasis (9 patients) and distant metastasis (4 patients; brain, liver, lungs, and mediastinum) were noted. Two patients died of disease. FNA smears were cellular and demonstrated mainly large, round cells with intracytoplasmic vacuoles or granules and round‐to‐oval nuclei with smooth nuclear contour, minimal irregularities, and prominent nucleoli arranged predominantly in clusters, papillary formations, and single cells. The background was variable and contained inflammatory cells, mucin, or proteinaceous material. The diagnoses were malignant (19 of 38 tumors; 50%), suspicious for malignancy (10 of 38 tumors; 26%), salivary gland neoplasm of uncertain malignant potential (7 of 38 tumors; 18%), and atypia of undetermined significance (2 of 38 tumors; 6%) according to the Milan System for Reporting Salivary Gland Cytopathology. Two malignant cases (2 of 40 tumors; 5%) were metastases. The neoplastic cells were immunoreactive for S100 (23 of 24 tumors), mammaglobin (18 of 18 tumors), GATA‐3 (13 of 13 tumors), AE1/AE3 (7 of 7 tumors), and vimentin (6 of 6 tumors). ETV6‐NTRK3 fusion was detected in 32 of 33 tumors by fluorescence in situ hybridization (n = 32) and next‐generation sequencing (n = 1).
CONCLUSIONS
Familiarity with cytomorphologic features and the immunohistochemical/molecular profile of SC can enhance diagnostic accuracy.;
... ACC tumors are round or nodular in shape, with unclear boundaries between the mass and surrounding tissue (1). Salivary ACC (SACC) accounts for 5-10% of salivary gland tumors, 24% of salivary gland malignancies and is usually located within the salivary glands (2). Although SACC may occur at any age, it predominately occurs in middle-aged and elderly individuals (aged 40-60 years), with no discrepancies in the incidence rates between males and females and this is more common in 40-60-year olds compared with individuals older than 60. ...
Circular RNA (circRNA/circ) hsa_circ_0011946 has been reported to serve an important role in a number of cancer types; however, to the best of our knowledge, its role in salivary adenoid cystic carcinoma (SACC) has not been reported. In the present study, the primary focus was the effects of hsa_circ_0011946 on the invasion, migration and epithelial-mesenchymal transformation (EMT) of SACC cells, and the specific mechanisms involved. The expression levels of hsa_circ_0011946 and microRNA (miR)-1205 in cancer tissues and paracancerous tissues of patients with SACC were analyzed using reverse transcription-quantitative (RT-q)PCR. The cell proliferation rate was determined using a Cell Counting Kit-8 assay. Wound healing assays were performed to analyze the cell migratory ability, while a transwell assay was used to measure the cell invasion ability. Western blotting was used to analyze the expression levels of EMT-related proteins. Cell transfection was used to knockdown hsa_circ_0011946 and knockdown or overexpress miR-1205. Subcellular localization assays for hsa_circ_0011946 were performed using RT-qPCR. A dual-luciferase reporter gene assay was used to verify the binding between hsa_circ_0011946 and miR-1205. The results of the present study revealed that the expression levels of hsa_circ_0011946 were significantly upregulated in cancer tissues from patients with SACC. The knockdown of hsa_circ_0011946 expression inhibited the proliferation, invasion and migration of SACC cells, thereby inhibiting the EMT process, which was achieved by downregulating miR-1205 expression. In conclusion, circRNA hsa_circ_0011946 was discovered to promote the malignant process of SACC by downregulating miR-1205 expression.
... Mucoepidermoid carcinoma is the most common malignant neoplasm in salivary glands and most commonly involves the parotid. 9 The amount of mucin seen on the smears depends on the tumor grade, with low-grade tumors commonly presenting as mucin and mucinous cells on cytology. 8 ...
The term “Atypia” has been employed to describe a wide spectrum of cytomorphologic features associated with reactive/inflammatory processes as well as those suspicious for neoplasms in cytology. Similar to other cytopathology reporting systems, the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) has reserved the atypical category for cytology specimens lacking quantitative and/or qualitative cytomorphologic features to be diagnosed with confidence as either non-neoplastic or neoplastic. In MSRSGC, the atypical category is associated with a risk of malignancy and recommendation for clinical management. In this review, we discuss the value of atypical diagnostic category of MSRSGC in both cystic and non-cystic salivary gland lesions by evaluating our institutional case cohort.
... In contrast, two cases each of adenoid cystic carcinoma and acinic cell carcinoma, categorized as SUMP, had cellular CBs which supported the neoplastic diagnoses in the present study. Of note, 43% of adenoid cystic carcinomas, acinic cell carcinomas and mucoepidermoid carcinomas were in a SUMP category in a large international multi-institutional study [37]. In an institutional study from the Memorial Sloan Kettering Cancer Centre, no acinic cell carcinoma nor adenoid cystic carcinoma were categorized as either a non-neoplastic or AUS category, but 33.3% of acinic cell carcinomas and 50% of adenoid were in a SUMP category [38]. ...
(1) Background: The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was introduced in 2018, bringing an organ-specific classification system for salivary gland cytopathology. The aim of present study is to evaluate the MSRSGC prospectively, based on a two-year experience in the tertiary care center pathology department, and evaluate the role of routine cell block (CB) preparation in salivary gland cytopathological diagnostics. (2) Methods: In our institution, the Department of Pathology, Fimlab Laboratories, Tampere, Finland, the MSRSGC has been implemented in salivary gland cytopathology since January 2018 and, over a two-year period (January 2018–December 2019), there were 365 fine-needle aspirations, of which 164 had a surgical follow-up. The CB methods used were Plasma-thrombin, the collection of visible fragments, and the Shandon and in-house methods. (3) Results: The MSRSGC diagnostic figures were as follows: accuracy 87.5%, sensitivity 45.8% and specificity 98.9%. For diagnostic categories of MSRSGC (non-neoplastic, benign neoplasm and malignant neoplasm) (n = 63) diagnostic accuracy was 98.4%, and for undetermined categories (atypia of undetermined significance, salivary gland neoplasm of uncertain malignant potential and suspicious for malignancy) (n = 49) diagnostic accuracy was 73.5%. Non-contributory cell blocks resulted more often in a false negative diagnosis (25%, 3/12) than a true negative diagnosis (10%, 7/73, p < 0.001), and is, most likely, an insufficient cytological diagnosis (86%, 18/21, p < 0.001). (4) Conclusion: The application of MSRSGC and CBs are beneficial in salivary gland cytological diagnosis, increasing diagnostic accuracy and, thus, patients’ management and treatment.
... Our study of 50 aspirates (including 9 cases of ACC-HGT) shows an overall DA of 64%, which increases to 74% if cases diagnosed as "suspicious for ACC" are included. Thus, the DA from our study slightly exceeds that from the 2019 multi-institutional study by Miller et al, 16 in which 32 of 55 ACC cases (58%) were precisely diagnosed with FNA cytology. However, these data cannot be directly compared because our study is a singleinstitution study, whereas Miller et al used data from 9 different centers. ...
Background
Although largely readily recognizable in tissue sections, acinic cell carcinoma (ACC) remains diagnostically problematic in fine‐needle aspiration (FNA) cytopathology. The authors undertook an analysis of a large series of ACC aspirates, including acinic cell carcinoma with high‐grade transformation (ACC‐HGT).
Methods
The authors searched their cytopathology files for ACC cases with histopathologic confirmation. FNA biopsy was performed according to standard techniques.
Results
Fifty FNA biopsy cases of ACC (including 36 of parotid origin [72%]) from 41 patients (female to male ratio, 1.4:1; age range, 23‐84 years; average, 54 years) met the study inclusion requirements. Primary neoplasm aspirates were most common (72%), and they were followed by recurrent tumors (16%) and metastases (12%). A precise cytologic diagnosis was made for 64%. Three of 9 ACC‐HGT cases (33%) were correctly interpreted as such; 98% of conventional ACC cases were correctly graded as low‐grade. With the Milan classification system, 74% fit into the malignant category. Ancillary testing was performed for only 36%. Conventional ACC had moderately to highly cellular smears; monotonous cells in aggregates and single forms; rounded nuclei; and microvacuolated, finely granular, oncocyte‐like, or nonspecific cytoplasm. ACC‐HGT smears contained larger nuclei, high nuclear to cytoplasmic ratios, coarse nuclear chromatin, and a loss of cytoplasmic granules/vacuoles.
Conclusions
A correct diagnosis of ACC via FNA biopsy was made in almost two‐thirds of the cases. With the Milan classification, 84% of the cases would have been classified as malignant or suspicious for malignancy. An absence of conventional serous acinar cell morphology in some cases as well as an absence of ancillary immunohistochemistry testing in almost two‐thirds of the cases prevented even better diagnostic performance.
... Main histological patterns of AdCC include cribriform, tubular and solid [1][2][3][4]. The more common cribriform and tubular variants typically show abundant extracellular matrix arranged in globules with well-defined borders partially surrounded by basaloid tumor cells [5][6][7], which is reflected as characteristic cytology features of scattered balls of mucopolysaccharide matrix material surrounded by cohesive cellular clusters [6,7]. However, in fine needle aspiration (FNA) specimens with abundant basaloid cells and lacking extracellular matrix materials, a broad differential diagnosis needs to be considered, including AdCC solid variant and other salivary gland tumors with overlapping morphology, such as pleomorphic adenoma (PA), basal cell adenoma/carcinoma, epithelial-myoepithelial carcinoma, and polymorphous low-grade adenocarcinoma [7][8][9][10]. ...
... Main histological patterns of AdCC include cribriform, tubular and solid [1][2][3][4]. The more common cribriform and tubular variants typically show abundant extracellular matrix arranged in globules with well-defined borders partially surrounded by basaloid tumor cells [5][6][7], which is reflected as characteristic cytology features of scattered balls of mucopolysaccharide matrix material surrounded by cohesive cellular clusters [6,7]. However, in fine needle aspiration (FNA) specimens with abundant basaloid cells and lacking extracellular matrix materials, a broad differential diagnosis needs to be considered, including AdCC solid variant and other salivary gland tumors with overlapping morphology, such as pleomorphic adenoma (PA), basal cell adenoma/carcinoma, epithelial-myoepithelial carcinoma, and polymorphous low-grade adenocarcinoma [7][8][9][10]. ...
... The more common cribriform and tubular variants typically show abundant extracellular matrix arranged in globules with well-defined borders partially surrounded by basaloid tumor cells [5][6][7], which is reflected as characteristic cytology features of scattered balls of mucopolysaccharide matrix material surrounded by cohesive cellular clusters [6,7]. However, in fine needle aspiration (FNA) specimens with abundant basaloid cells and lacking extracellular matrix materials, a broad differential diagnosis needs to be considered, including AdCC solid variant and other salivary gland tumors with overlapping morphology, such as pleomorphic adenoma (PA), basal cell adenoma/carcinoma, epithelial-myoepithelial carcinoma, and polymorphous low-grade adenocarcinoma [7][8][9][10]. An accurate FNA assessment is principal as it guides the level of aggressiveness of the surgical intervention, but due to significant morphologic overlap of basaloid cell neoplasm, a definite diagnosis is not always rendered. ...
Differentiating adenoid cystic carcinoma (AdCC) from other basaloid neoplasm in a fine needle aspiration (FNA) sample can be challenging. Activation of MYB in AdCC by the fusion transcript MYB-NFIB has been recently demonstrated in salivary gland and other organs. The aim of this study is to evaluate the utility of MYB immunohistochemistry (IHC) in distinguishing AdCCs and other basaloid neoplasm in cytology specimens. Eighteen FNA cases, from salivary gland and other sites, and their subsequent surgical resection specimens were included in the study. Eight cases were confirmed AdCC on resection. MYB IHC was performed on slides made from cytology cell block and surgical resection paraffin blocks. Percentage and intensity of nuclear staining in tumor cells was scored as 0 to 3. The staining results were concordant between cytology specimens and their corresponding surgical resection tumors. Strong diffuse nuclear staining (score 3, N = 5) was exclusively observed in AdCC, both in cytology and surgical specimens. Only one pleomorphic adenoma and one poorly differentiated basaloid carcinoma were positive for MYB staining (score 1 to 2). Any degree of nuclear MYB labeling was seen in 100% AdCC cases (N = 8/8) compared with of 20% (N = 2/10) of all other non-AdCC cases (P = < 0.001). The sensitivity and specificity of any degree MYB positivity for AdCC in cytology specimen is 100% and 78%. The sensitivity and specificity of strong diffuse MYB labeling (score 2 to 3) for AdCC is 83% and 100% in cytology specimen. Strong diffuse nuclear staining of MYB is valuable in supporting a cytologic diagnosis of AdCC. However, weak and focal labeling of MYB should be interpreted with caution as it can be seen in benign and other malignant basaloid lesions.
