Carcinoma ex pleomorphic adenoma of the salivary gland: an immunohistochemical study

Molecular Factors in Carcinoma Ex Pleomorphic Adenoma: Systematic Review and Meta-Analysis

OBJECTIVE

Carcinoma ex pleomorphic adenoma (CXPA) is a rare malignant salivary gland tumor. Although multiple reviews have been published on salivary gland malignancies, it has been a decade since the last dedicated systematic review pertaining to CXPA alone was published. This study examines molecular factors in CXPA diagnosis.

DATA SOURCES

MEDLINE, CINAHL, Embase, Scopus, Web of Science (BIOSIS), Cochrane CENTRAL, Health Collection (Informit), OpenDOAR, and GreyNet International.

REVIEW METHODS

Systematic review and meta-analysis from inception to October 31, 2022 for all English language studies pertaining to "carcinoma ex pleomorphic adenoma." Predicted incidence of each biomarker was calculated with meta-analysis. Comparison against pleomorphic adenoma (PA) and salivary duct carcinoma (SDC) when reported within the same study are performed. Risk of bias performed with JBI tool for prevalence studies.

RESULTS

Of 19151 unique studies undergoing abstract screening, 55 studies (n = 1322 patients) underwent data analysis. Biomarkers with >3 studies were p53, HER2, AR, EGFR, PLAG1, ERBB, ER, PR, HMGA2, p16, p63, a-SMA, RAS, PTEN, PDL1, BRAF, PIK3CA, and c-kit. Highest incidence was seen in AR, EGFR, p16, and p53. Significant differences were demonstrated compared with PA and SDC. There was high heterogeneity and overall high risk of bias within studies.

CONCLUSION

Molecular factors are an area of interest in the diagnosis of CXPA. Our study results support examining CXPA as a discrete cohort in future targeted therapy trials. Laryngoscope, 134:1042-1053, 2024.

Immunohistochemical analysis of proliferating cell nuclear antigen and minichromosome maintenance complex component 7 in benign and malignant salivary gland tumors

Background:

Proliferation markers have been used to determine the behavior and prognosis of benign and malignant tumors; this study was aimed to compare the immunohistochemical (IHC) expression of proliferating cell nuclear antigen (PCNA) and novel marker minichromosome maintenance complex component 7 (MCM7) in common salivary gland tumors including pleomorphic adenoma (PA), mucoepidermoid carcinoma (MEC), and adenoid cystic carcinoma (AdCC), to find a possible significant correlation between benign and malignant tumors.

Materials and Methods:

In this cross-sectional study, a total of 90 cases, including 30 PAs, 30 MECs, and 30 AdCCs, were collected. The IHC expressions of PCNA and MCM7 were evaluated. Their expressions were compared with each other and between benign and malignant tumors. Statistical analysis was performed by Chi-square and Tukey's test. P value was considered 0.05.

Results:

Out of 30 cases of PA, 28 cases (93.3%) were PCNA positive and 28 cases (93.3%) were MCM7 positive. In the AdCC cases, 29 cases (96.6%) were PCNA positive and 29 cases (96.6%) were MCM7 positive. In the MEC cases, all cases (100%) were PCNA positive and 23 cases (76.6%) were MCM7 positive. The labeling index (LI) of MCM7 and PCNA was evaluated, and this index was lower in MCM7 LI than PCNA in all tumors. The MCM7 and PCNA expression showed a significant difference in PA and MEC (P < 0.001).

Conclusion:

PCNA expression was higher than MCM7 expression in salivary gland tumors. However, more studies are needed to evaluate the malignant activity of these tumors with group of markers such as MCM family members.

Increase in Chymase-Positive Mast Cells in Recurrent Pleomorphic Adenoma and Carcinoma Ex Pleomorphic Adenoma of the Parotid Gland

Incomplete excision of pleomorphic adenoma (PA) may result in recurrent pleomorphic adenoma (RPA). Furthermore, long-term neglected PA may become carcinoma ex pleomorphic adenoma (CXPA). In the present study, the relationships between mast cell-derived chymase and these tumors were examined. The tumor tissues of PA consisted of either or both glandular and fibrotic structures. Histological features of RPA were almost similar to those of PA, except that they showed multinodular structures. CXPA is composed of a mixture of PA and carcinoma. The main stromal cells in PA were myofibroblasts, whereas fibroblasts constituted the main cellular portion in the stromal tissue of RPA. Cancer-associated fibroblasts (CAFs) were present abundantly in CXPA. With increased VEGF expression, neovascularization tended to increase in RPA or CXPA. Compared with PA, chymase-positive mast cells, as well as chymase gene expression, were increased in the tumor tissues from patients with RPA or CXPA. SCF, TGFβ1, and PCNA-positive staining was widely observed in these tumor tissues. The above results suggest that mast cell-derived chymase through its direct or cooperative effects with other mediators may participate in the pathophysiology of RPA and CXPA.

Outcomes of carcinoma ex pleomorphic adenoma compared to de novo adenocarcinoma of major salivary glands

BACKGROUND AND OBJECTIVES

Carcinoma ex pleomorphic adenoma (CXPA) is a rare disease of the major salivary glands that remains poorly characterized. Our objective was to compare the clinical outcomes of patients with CXPA of the major salivary glands to those with de novo adenocarcinomas.

METHODS

Review of the NCDB between 2004 and 2016 to compare cases of CXPA and adenocarcinoma of major salivary glands. Demographics, clinical characteristics, and survival were analyzed.

RESULTS

We identified 1181 patients with CXPA and 3326 patients with adenocarcinoma of major salivary glands. Adenocarcinomas presented with higher rates of nodal metastasis (54.7% vs. 30.4%, p < .001). Five-year survival of adenocarcinoma (55.8%) was worse than that of CXPA (68.5%, p < .001). When stratified by nodal status, there was no significant difference in 5-year survival between CXPA and adenocarcinoma node-negative (75.3% vs. 71.6%, respectively) and node-positive (40.4% vs. 36.1%, respectively) patients.

CONCLUSIONS

CXPAs of the major salivary glands present at an earlier stage with lower rates of regional metastasis compared to adenocarcinomas. After controlling for lymph node metastases, the outcomes are quite similar.

Maxillofacial diagnostic features of the enigmatic metastasizing pleomorphic adenoma

Considering the confusion in the literature regarding local recurrence, spread, or metastases of pleomorphic adenoma (PA) in the head and neck region, the aim of this study was to enhance understanding of the characteristics of metastasizing pleomorphic adenoma (MPA) by reviewing the literature and presenting a case. English language articles with proof of metastases were included in the literature review. Of the 80 cases in the literature with MPA, 46 were female and 33 were male (sex missing for one case). Thirty-five percent of the neoplasms affected the bones; the maxilla was affected in five cases and the mandible in three. The parotid was the primary site in 72.5% of cases and the submandibular gland in 16.2% of cases. The local recurrence rate was 70%. The mean interval between primary PA and MPA was 15.52 years. The total mortality rate was 8.7%. A case of PA of the submandibular gland that recurred after surgical excision and metastasized (confirmed by the presence of intact cortical borders) to the ipsilateral mandibular body, upper lip, and neck is described. The high mortality rate in a histologically defined benign disease that metastasizes demands that management include careful primary excision and long-term clinical follow-up.

The Difference in the Clinical Features Between Carcinoma ex Pleomorphic Adenoma and Pleomorphic Adenoma

Carcinoma ex pleomorphic adenoma (CXPA) arises from the primary or recurrent benign pleomorphic adenoma. The purpose of this study was to evaluate the clinical features that could be referenced in the differentiation. The medical records of 221 patients with pleomorphic adenoma and 15 patients with CXPA were retrospectively reviewed. Clinical characteristics, computed tomography and magnetic resonance imaging findings, and surgical pathology were analyzed. Patients with CXPA were older (55.1 vs 42.3; P < .01). Carcinoma ex pleomorphic adenoma was observed at higher rates in the minor salivary glands (24.9% vs 2.7%) and higher incidence of regional lymph node enlargement (P = .04). While all CXPA showed a low-to-intermediate mean apparent diffusion coefficient value (ADC), most of pleomorphic adenoma had an intermediate-to-high (P = .01). From this study, the following features should be considered as the clinical features of CXPA: (1) old age; (2) minor salivary gland tumor; (3) regional lymph node enlargement (>5 mm); and (4) low ADC findings.

Fatty acid synthase and Ki-67 immunoexpression can be useful for the identification of malignant component in carcinoma ex-pleomorphic adenoma

BACKGROUND

Fatty acid synthase (FASN) is the key molecule for catalyzing fatty acid synthesis and have been associated with several malignant tumors.

METHODS

We analyzed the expression of FASN and Ki-67, by immunohistochemistry on 29 carcinomas ex-pleomorphic adenoma (CXPAs) and 25 pleomorphic adenomas (PAs).

RESULTS

Ki-67 proliferation index and FASN expression were significantly higher in patients with CXPA than patients with PA (P < 0.001). We found intense immunoreactivity for FASN in the malignant component of CXPAs, and these malignant areas also had intense nuclear immunoreactivity for Ki-67.

CONCLUSIONS

The present results suggest that overexpression of FASN in CXPAs might be associated with malignant transformation of ductal epithelial cells and/or myoepithelial cells from PA. FASN associated with Ki-67 may be useful diagnostic markers for CXPA.

Carcinoma ex-pleomorphic adenoma of the parotid gland consisting of high-grade salivary duct carcinoma and keratinizing squamous cell carcinoma

Carcinoma ex-pleomorphic adenoma (CXPA) is a rare salivary gland malignancy that presents diagnostic difficulties partly because of its wide range of histologic presentations. We report a case of a 77-year-old man, who presented with a 6-year history of a parotid mass that had undergone rapid growth within weeks. Magnetic resonance imaging revealed an infiltrative mass in the parotid gland, and the fine-needle aspiration (FNA) biopsy result was highly suspicious for carcinoma. Subsequent excision of the tumor demonstrated a poorly differentiated epithelial neoplasm consisting of keratinizing squamous cell carcinoma (SCC) and adenocarcinoma with regions of both ductal carcinoma in situ and invasive salivary duct carcinoma (SDC). Only focal areas exhibited a benign pleomorphic adenoma component. To our knowledge, this is the first case of a CXPA that consists of both a high-grade SDC and a keratinizing SCC in the parotid gland.

Carcinoma ex pleomorphic adenoma of the palate composed of invasive micropapillary salivary duct carcinoma and adenoid cystic carcinoma components: an unusual case with immunohistochemical approach

Carcinoma ex pleomorphic adenoma (CXPA) is an unusual epithelial malignancy that develops from a primary or recurrent pleomorphic adenoma (PA), the most common tumor of salivary glands, and constitutes about 11.5% of all carcinomas that affect these glands. Intraoral minor salivary glands and seromucous glands of the oropharynx are uncommon locations of CXPA. On histopathological examination, the tumor comprises a wide morphological spectrum with a variable proportion between the benign and malignant components with the latter often predominating and overlapping the PA, which may cause misdiagnosis. Here, we report a case of palatal minor salivary gland CXPA composed of invasive micropapillary salivary duct carcinoma and adenoid cystic carcinoma components with multiple nodal metastases in a 74-year-old woman. Neoplastic cells showed heterogeneous immunohistochemical profile with both luminal and myoepithelial differentiation. The invasive micropapillary salivary duct carcinoma component demonstrated overexpression of the oncoprotein human epidermal growth factor receptor-2. This feature should be considered and evaluated as a possible target for adjuvant therapy in case of metastatic disease.

Salivary duct carcinoma with rhabdoid features: report of 2 cases with immunohistochemical and ultrastructural analyses

BACKGROUND

Salivary duct carcinoma with rhabdoid features is extremely rare.

METHODS

We report 2 cases of salivary duct carcinoma with rhabdoid features treated at our institution.

RESULTS

Case 1 was a 44-year-old Japanese man who had swelling in the left parotid region. This tumor consisted of residual pleomorphic adenoma and widely invasive carcinoma, which showed a diffuse growth pattern by atypical rhabdoid cells. Case 2 was a 66-year-old Japanese man who had swelling of the right cervical region. This submandibular tumor was also composed of both residual pleomorphic adenoma region and invasive adenocarcinoma components, whereas some metastatic lesions were purely composed of rhabdoid cells. Such cells were strongly and diffusely positive for cytokeratins (CKs), gross cystic disease fluid protein-15 (GCDFP), and androgen receptor (AR). Case 1 was also positive for Her-2 and p53.

CONCLUSION

Both patients were diagnosed with carcinoma ex pleomorphic adenoma and their carcinomatous components were composed of salivary duct carcinoma with rhabdoid features, which is a highly aggressive tumor, similar to salivary duct carcinoma.

A case of metastasizing pleomorphic adenoma in the maxillary bone appearing twenty years after initial resection of pleomorphic adenoma of the hard palate

Metastasizing pleomorphic adenoma (MPA) is the inexplicable metastasis of a histologically benign pleomorphic adenoma (PA). Approximately 50 cases have been reported. A 62-year-old woman noticed pain in the upper molar area. Her medical history included an operation for PA in the hard palate that was performed 20 years previously. On imaging, four relatively well-defined lesions were demonstrated in the maxillary bone. She underwent an operation for these lesions. Each lesion revealed the same histological features. Morphological findings displayed typical features of PA. Immunohistochemical staining showed that tumor cells of both primary and metastasizing lesions were positive for pleomorphic adenoma gene (PLAG) 1, which is a sensitive marker for PA. Gene fusions involving PLAG1 were examined by reverse transcription-polymerase chain reaction. However, no gene rearrangements of PLAG1 were found. We report here on a case of MPA in the maxillary bone, which appeared 20 years after resection of the primary tumor and review the relevant literature.

Canine mammary mixed tumours: a review

Mammary mixed tumours are the most frequent neoplasias in female dogs. In humans, mixed tumours are frequently found in the salivary glands and are known as pleomorphic adenomas. In addition to their histomorphologic similarities, mixed tumours and pleomorphic adenomas have the potential to become malignant and give rise to carcinomas in mixed tumours and carcinomas ex-pleomorphic adenoma, respectively. The factors associated with malignant transformation are still poorly known in the case of canine mixed tumours. However, this form of neoplasia tends to be associated with a better prognosis than other malignant histological types. This paper discusses the main features associated with female canine mammary mixed tumours.

Comparison of Ki-67, cyclin E, and p63 in benign and malignant human pleomorphic adenoma

OBJECTIVE

A set of cell proliferation-related molecular markers was used to detect the differences in proliferative activity between benign pleomorphic adenoma (PA) and carcinoma ex pleomorphic adenoma (CXPA).

STUDY DESIGN

Seventy samples comprising 53 PAs, 10 noninvasive and 7 widely invasive (WI) CXPAs were selected. Immunohistochemical staining was used to detect Ki-67, cyclin E, and p63 expression.

RESULTS

The average Ki-67 labeling index of WI CXPAs was higher than that of PAs and the malignant component of noninvasive CXPAs (M-noninvasive CXPA; P < .01). An increased cyclin E-positive staning was observed in M-noninvasive CXPAs and WI CXPAs compared with PAs (P = .006). The p63 expression levels were notably decreased in M-noninvasive CXPAs and WI CXPAs compared with PAs (P = .007).

CONCLUSIONS

The data support that increased or decreased expression of Ki-67, cyclin E, and p63 may indicate the proliferative differences between PA and CXPA.

Carcinoma ex pleomorphic adenoma of the buccal region is composed of salivary duct carcinoma and squamous cell carcinoma components

A 73-year-old female presented with an asymptomatic mass in the left buccal region that she had first noticed 4 years earlier. The tumor, which was located in the buccal space, was clinically diagnosed as a salivary gland tumor and treated by excision. Histopathological examination revealed a capsule of connective tissue consisting of three different histopathological neoplastic areas in a large, fibrous, hyalinizing stromal background. The neoplastic lesion contained two malignant and one benign element, with histological characteristics consistent with squamous cell carcinoma (SCC), salivary duct carcinoma (SDC) and pleomorphic adenoma (PA). The SCC nests showed no continuity with the buccal mucosa. Both the SCC and SDC nests were surrounded by non-atypical myoepithelial cells, suggesting that both components may have developed from transformation of metaplastic luminal epithelial cells of PA. The tumor was diagnosed as a non-invasive carcinoma (SCC and SDC) ex pleomorphic adenoma (Ca-ex-PA). There was no evidence of recurrence 16 months after operation.

Ki67 and salivary cancer

We examined Ki67 expression in salivary malignancies of 75 patients with a follow-up period of up to 20 years. Correlations between enhanced Ki67 and enhanced p53 and TUNEL and heparanase staining levels were significant. Median survival for reduced-stained-tumor patients (< or = 5%) was 163 months, dropping significantly to 39 months (p = 0.0005) for enhanced stained tumors (> 5%); 5 year survival probability was 93% and 33%, respectively, 45% and 16%, respectively, (p = 0.0005) at 20 years. Significant correlation between poor survival and concurrently altered expression rates of Ki67 and p53, p27 Skp2, TUNEL and heparanase in the salivary malignancies indicates a biological role in salivary cancer pathogenesis.

New agents in the treatment for malignancies of the salivary and thyroid glands

The treatment of relatively rare malignancies, such as those of the salivary glands and iodine refractory thyroid cancer, has been invigorated by the development of novel molecular targeting agents. Accrual to clinical trials for these disease sites continues to be limited by their relatively low incidence. Nonetheless, multicenter collaborations have contributed greatly to the development of a number of emerging systemic therapies. This article briefly summarizes the epidemiology and pathogenesis of salivary gland and thyroid cancer, and then describes some of the new drugs under evaluation for these malignancies.