Epithelial and stromal patterns of pleomorphic adenoma of minor salivary glands: A histopathological and histochemical study

Oral cavity salivary gland pleomorphic adenoma: a histomorphological case series

BACKGROUND

Pleomorphic adenoma (PA), the most common benign salivary gland epithelial lesion, has a biphasic epithelial-mesenchymal pattern and great histopathological diversity.

METHODS

This study's objective was to conduct a retrospective clinicopathological analysis, focusing on the histopathology characteristics of salivary gland PA.

RESULTS

There were ten cases of pleomorphic adenoma. The mean age was 33.5 years and no gender predilection was observed. All the patients presented with an asymptomatic mass and the duration of presentation was 31.2 ± 19.4 months. The cellular subtype (50 %) of PA was the most common. Capsular infiltration and incomplete capsules occurred in 20 % of cases. All the cases had round (100 %) and myxoid stroma. The cellular subtype was more common in the major salivary glands; showed capsular abnormalities (incomplete capsule, absent capsule, and tumor infiltration); and had more plasmacytoid, angular, spindled non-luminal cells as well as inflammation and cystic degeneration. The classic subtype had more clear and oncocytic cells along with sebaceous and squamous differentiation. The stroma-rich subtype had the shortest duration of complaints (three months) and showed giant cell reaction.

CONCLUSIONS

These findings confirm previous studies on the clinicopathological features of pleomorphic adenomas and highlight important morphologic characteristics like capsular invasion and squamous metaplasia, which can otherwise indicate malignancy.

Differential Expression of Mucin in Salivary Gland Tumours

Background and Objectives: Mucin has been implicated via various mechanisms in the development and growth of tumour cells. However, mucin expression studies in salivary gland tumours are limited, especially with samples from minor salivary glands. This study aims to investigate and compare mucin expression in benign and malignant salivary gland tumours of minor and major salivary gland origins. Materials and Methods: Special stains were used to stain neutral mucin (Periodic acid Schiff), sialomucin (Alcian Blue) and sulfomucin (Aldehyde Fuschin) within tissues from six normal salivary glands and 73 salivary gland tumours including 31 pleomorphic adenomas, 27 mucoepidermoid carcinomas, and 15 adenoid cystic carcinomas. A semi-quantitative approach was used to evaluate mucin expression within ductal lumens. Sialomucin was the most expressed mucin in all salivary gland tumours, regardless of origin. Results: A significant difference was observed in the mucin expression between benign and malignant salivary gland tumours, as pleomorphic adenoma showed three times significantly higher expression of sialomucin compared to mucoepidermoid carcinoma and adenoid cystic carcinoma (p = 0.028). Pleomorphic adenomas of major glands showed 42 times significantly higher expression of sialomucin compared to those of minor glands (p = 0.000). Conclusions: Sialomucin content in pleomorphic adenomas of major glands was vastly increased compared to that in minor glands. Differential sialomucin expression in benign and malignant salivary gland tumours suggests a role in diagnosing of borderline salivary gland tumours.

"Pleomorphic adenoma in salivary glands: Insights from a 100-patient analysis"

Introduction

Pleomorphic adenoma (PA) is a benign epithelial tumour originating from the salivary gland, specifically the parotid gland. This study aims to comprehensively analyse the clinical and pathological features of PA by examining the characteristics of the tumour, including its histological structure and immunohistochemical profile.

Materials and Methods

Over 8 years, beginning in October 2015 and ending in October 2023, an exhaustive retrospective study was conducted in the Department of Pathology, Kasturba Medical College, Mangalore, Manipal University, Karnataka, India. The research focused on 100 cases of pleomorphic adenoma and involved a meticulous examination of the clinical and pathological characteristics obtained by retrieving the pertinent files.

Results

Out of all the primary tumours, the majority (n = 70) was found in the parotid gland, followed by PA that developed from the minor salivary glands of the palate (n = 07), the submandibular gland (n = 17), and the lacrimal gland (n = 04). Only two cases had a primary tumour located in the lips. Females were more susceptible to these tumours than males. The parotid gland tumours showed a distinct trend in laterality, with 73 cases observed on the right side. In 85%, the initial symptom of the condition was painless swelling.

Conclusion

Salivary gland PA is typically a benign tumour. However, a subset of these tumours can exhibit a malignant phenotype. The preferred treatment is surgical excision with adequate margins.

Correlation of Clinical and Histopathological Features of Salivary Pleomorphic Adenoma

Statement of the Problem

Salivary gland tumors represent about 3% of the head and neck tumors. Pleomorphic adenoma (PA) is the most common benign salivary gland tumor.

Purpose

This study was conducted to investigate and describe some clinical and histopathological aspects of salivary pleomorphic adenomas with special reference to the epithelial and mesenchymal components.

Materials and Method

In this retrospective study, one hundred tissue samples diagnosed as PA were sourced from archival tissue blocks between 2009 and 2019 in this retrospective study. Some clinical and demographic features, including age, sex, tumor size, and tumor location were recorded. This study included only samples taken by excisional biopsy. Then, the samples were histologically classified into three subtypes according to the proportion of epithelial and stromal components. The demographic and clinicopathological variables were statistically analyzed using Chi-square test or Fisher's exact test, considering a significance level of 5% (p< .05).

Results

In the present study, most cases (61%) were found in females, representing a female-male ratio of 1.6:1. The peak incidence was seen in the 4th and 5th decades of life. In 87% of cases, PA occurred in major salivary glands. There was a significant difference between the age of the patient and squamous metaplasia (p= 0.036). There was also a significant difference between the size of tumor and the amount of myxoid stroma (p= 0.021). Extensive myxoid stroma was mostly seen in tumors larger than 3.37cm (p= 0.001). In addition, there was a statistically significant difference between capsular invasion and the development of squamous metaplasia (p= 0.001).

Conclusion

In this study, there was a significant correlation between the gland type and capsular features and between the size of tumor and rate of squamous metaplasia. A detailed clinical and histopathological analysis of PAs may provide a better insight to the pathophysiology of the lesion, tumor cell differentiation, and prognostic factors.

Novel Discovery of the Somatostatin Receptor (SSTR2) in Pleomorphic Adenomas via Immunohistochemical Analysis of Tumors of the Salivary Glands

Reliable preoperative diagnosis between salivary gland tumor entities is difficult. In this monocentric retrospective study, we examined the somatostatin receptor 2 (SSTR2) status of salivary gland tumors after salivary gland tumor resection via immunohistochemistry (IHC), and stains were compared in analogy to the HER2 mamma scale. A total of 42.3% of all pleomorphic adenoma (PA) tumors (42 of 99, 95% confidence interval 32.5-52.8%) demonstrated ≥20% of cells displaying the SSTR2 as compared to just 1% of all other tumors (1/160, 95% CI 0.02-3.4%). The other tumor was a neuroendocrine carcinoma. PA had a higher intensity of SSTR2 staining, with 90.9% staining ≥ an intensity of 2 (moderate). Tumors with an intensity of SSTR2 expression equal to or greater than 2 had an 89.9% likelihood of being a PA (95% CI: 82.2-95.0%, AUC: 0.928). Only one Warthin tumor demonstrated a 'strong' SSTR2 staining intensity. No Warthin tumor showed a percentage of cells staining for SSTR2 above ≥20%. This result demonstrates consistent and strong expression of SSTR2 in PAs as compared to Warthin tumors, which may allow physicians to utilize radioligand-somatostatin analog PET CT/MR imaging to diagnose the PA. SSTR2 positivity, if shown to be clinically relevant, may allow peptide receptor radionuclide therapy in the future.

CD24-gold nanocomposite as promising and sensitive biomarker for cancer stem cells in salivary gland tumors

Cancer stem cells are highly tumorigenic cells in the majority of the tumor that are responsible for the initiation, rapid growth, invasion, metastasis, and therapeutic resistance associated with various human cancers. The aim of this project is to assess a diagnostic and prognostic biomarker for the detection of cancer stem cells in salivary gland tumors using gold nanoparticles that are synthesized and conjugated to CD24 primer to form a CD24-Gold Nanocomposite. Sixty cases were included (29 pleomorphic adenoma, 19 carcinoma ex pleomorphic adenoma, and 12 normal controls). Alterations in biomarker expression between studied groups were analyzed and correlated with clinicopathological characteristics using Fisher's exact and Chi-square tests. ROC and Kaplan-Meier curves were used to validate diagnostic and prognostic values, respectively. This study confirms that CD24-Gold Nanocomposite served as a promising and highly sensitive biomarker in salivary gland tumor diagnosis and prognosis prediction.

Comparative Longitudinal Analysis of Malignant Transformation in Pleomorphic Adenoma and Recurrent Pleomorphic Adenoma

Background: Recurrence in pleomorphic adenoma (PA) has been debated as a risk factor for malignant transformation (MT). In this study, we investigated whether recurrence is a risk factor for MT, by longitudinally analyzing cases with recurrent PA (RPA), and carcinomas from PA (CXPA) or RPA (CXRPA). Methods: The study population included 24 CXPA, 24 RPA, 6 CXRPA, and 386 PA cases (study period 2010−2018). Time and event data were collected from the medical documents to identify the time−event sequences. Results: The time interval to MT in CXRPA was significant longer than that of benign recurrence (median 342.0 vs. 109.5 months). In CXRPA, the recurrence intervals were not shorter than those in RPA according to recurrence frequency. Crudely, the MT rate was 5.9% among primary cases and 20.0% among recurrent cases. However, the time-adjusted MT rates increased up to 11.4% (incubation time > 60 months) and 20.0% (>120 months) in primary cases, which were not different from recurrent cases. Conclusion: In these longitudinal analyses, we did not find any clinical evidence that recurrence facilitates MT in the background of PA. Instead, a long incubation time seems to be a key factor for MT of underlying RPA.

Hyalinization as a histomorphological risk predictor in oral pathological lesions

Background

Hyalinization is a process of conversion of stromal connective tissue into a homogeneous, acellular translucent material. Nevertheless, hyalinization could provide insights into the biologic behaviour and prognosis of pathological lesions. Few studies with limited sample size have intended to assess the correlation of hyalinization and biologic behaviour in oral lesions.

Aim

The current review aims to comprehensively appraise the mechanism of hyalinization in pathological oral hyalinizing lesions (OHL) and its clinical implications with emphasis on differential stains employed.

Methods

An electronic search was performed in the PubMed database (from year 2000-2020) using the keywords "special stains in oral hyalinizing lesions", "significance of hyalinization in oral lesions" and "hyalinization and biologic behaviour". Original research articles analyzing the effect of hyalinization on biologic characteristics of the lesion were evaluated in this review. Narrative review articles that provided insights into the mechanism of hyalinization and maturity of collagen fibers were also considered for analysis.

Conclusion

The presence of hyalinization does seem to have a significant effect on the biologic behaviour of pathological lesions. There is substantial scope to further investigate the process of hyalinization on larger samples and its correlation with the aggressive behaviour of OHLs. Special stains and advanced investigations such as immunohistochemistry for stromal markers would define the nature of hyalinized material and validate the correlation.

Clinical significance

The prediction of the biologic behaviour of a lesion established through assessment of hyalinization would prevent unwanted over or under treatment leading to a better prognosis.

State of knowledge: Histolocalisation in phytochemical study of medicinal plants

BACKGROUND AND AIM

The renewed interest in medicinal plants has led us to examine more closely the usefulness of metabolite histolocalisation in screening work before any in-depth phytochemical studies. Indeed, this method is a histochemical technique allowing characterizing plant tissues constituents; and in particular metabolites of therapeutic interest, without destroying or altering as much as possible the studied plant material. This work aims at allowing us carring out a wide screening to highlight bioactive metabolites in plants studied from our rich university heritage collection.

MATERIAL AND METHODS

The histochemical characterisation used in our work is a chemical, morphological and topographical (localisation) technique that uses precipitation reactions using dyes, among others. To do this we made thin cross-sections using razor blades on fresh plant material. The sections were then coloured using conventional chemical stains and observations were made using a MOTIC BA210 microscope equipped with a MOTICAM camera.

RESULTS AND CONCLUSION

In view of obtained results, this technique, therefore, proves to be a useful screening and analysis method when applied in phytochemical studies on plants such as Datura stramonium, Peperomia obtusifolia, Cecropia obtusa, Orthosiphon aristatus and Vitex agnus castus. The obtained results confirm presence of sought metabolites, and allow their precise histological localisation. This will make extraction process more profiTable, simpler or even more ecological by avoiding waste.

Characterization of vascular density and collagenous matrix in oral pleomorphic adenomas

BACKGROUND

Tumor vascular density and collagen matrix organization are critical factors to neoplasia development and progression. This study aimed to analyze the variables associated with the extracellular matrix in oral pleomorphic adenomas.

METHODS

This cross-sectional study comparatively evaluated 21 cases of pleomorphic adenomas and 21 sections of regular oral mucosa from the files of an oral pathology department. The tissue sections were subjected to immunohistochemical study with a monoclonal antibody specific to CD31 protein to assess vascular density and were also stained with Sirius red to evaluate the levels of collagen. The numbers of positively-stained cells were enumerated in specific fields through morphometric study, with subsequent statistical analysis.

RESULTS

Higher numbers of CD31-positive cells were observed in tumor cells than in cells in the regular oral mucosa (P=0.004), which were always located around blood vessels. In tumor lesions, the correlation between the collagen area and vascular density was discrete between these two variables (r=0.046), although the association was not statistically significant.

CONCLUSIONS

The results suggested that the increased expression of CD31+ in cells associated with capillaries may be related to tumor neoangiogenesis. Furthermore, an increase in the concentration of collagen fibers proportional to the number of blood vessels in the neoplastic sections suggested the active role of these lesions in the remodeling process.

Diagnosis and treatment for central Mucoepidermoid Carcinoma in the mandible: Report of a clinical case in a young patient

A clinical case of a 13 year old male patient with a malignant tumor in the mandibular body area with two years of evolution and associated pain is reported. It was initially diagnosed as low grade central mucoepidermoid carcinoma through Hematoxylin and Eosin (H-E) staining in multiple biopsies. Considering the clinical and radiographic characteristics of the lesion, it was necessary to confirm the diagnosis through Periodic acid-Schiff (PAS). The treatment involved hemimandibulectomy, neck emptying, and complementary radiotherapy. This article aims to present a rare occurrence of this type of intraosseous malignant tumor of glandular origin in a young patient.

Key words:Mucoepidermoid carcinoma, periodic acid Schiff reaction, pathology, surgery, radiotherapy.

Clinicopathological study of 74 palatal pleomorphic adenomas

BACKGROUND/PURPOSE

Pleomorphic adenoma (PA) is the most common salivary gland tumor and the palate is the most common intraoral site for PA. This study aimed to present the clinicopathological features of a series of 74 palatal PAs.

METHODS

Seventy-four palatal PAs were collected from 1993 to 2009. The clinical and histopathological features of these 74 PAs were reviewed and analyzed.

RESULTS

The 74 palatal PA patients showed a marked female predilection (49:25, ∼2:1) and were nearly evenly distributed from the 3rd to 8th decades of life with a mean age of 47 years. All palatal PAs were treated by wide surgical excision and recurrence was noted in one PA. Histopathologically, there were 47 classic and 27 cellular PAs. Of the 74 PAs, 12 were completely encapsulated, 40 partially encapsulated, and 22 nonencapsulated. The duct-like structures and myxoid stroma were more or less found in every palatal PA. Plasmacytoid myoepithelial cell, clear cell, squamous epithelial nest, keratin pearl, hyalinized stroma, osteoid area, and chondroid area were found in 50, 19, 29, 19, 49, eight, and six PAs, respectively.

CONCLUSION

We conclude that the palatal PA patients show a prominent female predilection (2:1) and are nearly evenly distributed from 20 years to 79 years of age. Plasmacytoid myoepithelial cell is the most characteristic type of tumor cell in PAs. Wide surgical excision is treatment of choice for PAs. Although ∼84% of palatal PAs are partially or nonencapsulated, recurrence of the lesion is rarely encountered after total surgical removal of the tumors.