Immunohistochemical Profile of Polymorphous Adenocarcinoma of Minor Salivary Gland: A Systematic Review and Meta-Analysis

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

PURPOSE

This study describes a large, well-documented case series of salivary gland polymorphous adenocarcinomas (PAC) from a single Brazilian center.

METHODS

Demographic data, clinical presentation, histopathological and immunohistochemical features from 26 cases of PAC were analyzed and discussed in detail.

RESULTS

Most patients were females (n = 21), with a ratio of 1:4.2 (male: female) with a mean age of 58.8 years (ranging from 36 to 84 years). The most common clinical presentation was a fibrocollagenous, firm nodular lesion, with a mean size of 2.46 cm (ranging from 0.5 to 3 cm). 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%.

CONCLUSION

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.

The basaloid-spectrum of salivary gland tumors: A focused review with practical diagnostic considerations

Basaloid salivary gland neoplasms are a diverse and varied group of benign and malignant tumors. The term 'basaloid' is broadly used in reference to cells with elevated nuclear to cytoplasmic ratio, sparse cytoplasm, and hyperchromatic nuclei. However, a subset may also fit within the "small round blue cell tumor" morphologic category or the "biphasic" salivary gland tumor category. Furthermore, there are no established thresholds for the proportion of basaloid tumor cells needed to consider a tumor within the basaloid spectrum. Given the implicit variability in what is considered a basaloid salivary gland tumor, one may question the inclusion of certain entities (canalicular adenoma, HMGA2::WIF1 pleomorphic adenoma, polymorphous adenocarcinoma) in this review based on classic morphologic features. However, salivary gland tumors with even minor basaloid components may appear 'basaloid' in small biopsy specimens and, thus, a choice was made to focus on common and uncommon diagnostic differentials with this in mind. Entities that will be covered in this review also include basal cell adenoma and basal cell adenocarcinoma, adenoid cystic carcinoma, lymphoepithelial carcinoma, sialoblastoma, adamantinoma-like Ewing Sarcoma, NUT carcinoma, and carcinoma showing thymus-like differentiation.

Proceedings of the 2024 North American Society of Head and Neck Pathology Companion Meeting, Baltimore, MD, March 24, 2024: Navigating Ancillary Studies in Basaloid/Blue Salivary Tumors

BACKGROUND

Basaloid salivary tumors can demonstrate significant morphologic overlap and be challenging to diagnose.

METHODS

A review of select ancillary studies in basaloid salivary tumors was performed.

RESULTS

A number of immunohistochemical stains, including PLAG1, HMGA2, β-catenin, MYB, and RAS Q61R, have been more recently incorporated into the diagnostic workup of basaloid salivary tumors.

CONCLUSIONS

Although reported variability in their performance has perhaps limited their widespread adoption, these immunohistochemical studies can nevertheless be useful in supporting pathologic diagnoses, particularly when considered in more specific differentials or when used as a panel with other markers.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

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.

Fulminant Adenoid Cystic Carcinoma of the Maxillary Sinus - A Rare Finding: Case Report

BACKGROUND

The most common malignant tumor of the small salivary glands in the head and neck region is adenoid cystic carcinoma (ACK). The most common localization of ACK is the hard palate. ACK does not show any sex predisposition and is mainly diagnosed in middle-aged patients.

CASE REPORT

The present case report describes a fulminant ACK in the rare localization of maxillary sinus in a 36-year old male. The subsequent surgical treatment consisted of a radical hemimaxillectomy using an extraoral approach according to Weber-Fergusson-Dieffenbach and ipsilateral neck dissection. A magnetic epithesis was used for initial defect coverage of the maxillary bone accompanied by an obturator prosthesis. The surgical treatment was then followed by adjuvant proton therapy.

CONCLUSION

This case report shows how individual patient care can be provided according to the latest therapy standards of ACK in the rare localization of the maxillary sinus.