Malignant Pleomorphic Adenoma Research Articles

Extra-Parotid Pleomorphic Adenoma and Low-Grade Salivary Malignancy in the Head and Neck Region.

Background and objective Pleomorphic adenoma is the most common major salivary gland neoplasm. Around 80% of them arise in the parotid glands, whereas 10% originate in the minor salivary glands. The pleomorphic adenoma of the extra-parotid site is defined by its location outside the primary salivary gland. The minor salivary gland adenomas occur at the hard and soft palate, lips, tongue, lacrimal glands, pharynx, larynx, paranasal sinus, and nasal cavity. Pleomorphic adenoma in parapharyngeal space may occur de novo or as an extension of the deep lobe of the parotid tumors. Our objective in this study wasto assess the location and presentations of extra-parotid pleomorphic adenomaand frequency of low-grade salivary gland malignancy diagnosed as pleomorphic adenomavia fine-needle aspiration cytology (FNAC)in the head and neck region andthe treatment outcomes after the resection of the tumors. Materials and methods This was a retrospective observational study. All patients with FNAC-diagnosedpleomorphic adenoma of extra-parotid locations of the head and neck region who underwent curative surgery in the Department of Otorhinolaryngology and Head and Neck Surgery at a rural tertiary care center between August 1997 and August 2022 were included in the study. Data on the symptoms, FNAC report, surgical techniques, pathological results, adjuvant therapy, andany recurrence were documented. Data were entered into a Microsoft Excelsheet and analyzed using IBM SPSS Statistics version22 software (IBM Corp., Armonk, NY). Results Our study included 23 patients, of which 14 were females and nine were males. The various sites of involvementwere as follows: parapharyngeal space (four), larynx (one), nasal septum (two), hard palate (five), soft palate (four), hard and soft palate (three), and submandibular salivary gland (four). Of note, 17.3% of the patients had local recurrence withan average time frame of three years post-surgery: 20% in patients with low-grade malignancy and 16.6% in patients with pleomorphic adenoma. Conclusion Extra-parotid pleomorphic adenomas are common and have a high malignant potential. The preferred choice of treatment for extra-parotid salivary tumors is complete resection with adequate clearance. Malignant pleomorphic adenomas may require stagingneck dissection and adjuvant treatment for a better prognosis.

Integrated weighted gene coexpression network analysis identifies Frizzled 2 (FZD2) as a key gene in invasive malignant pleomorphic adenoma

BackgroundInvasive malignant pleomorphic adenoma (IMPA) is a highly malignant neoplasm of the oral salivary glands with a poor prognosis and a considerable risk of recurrence. Many disease-causing genes of IMPA have been identified in recent decades (e.g., P53, PCNA and HMGA2), but many of these genes remain to be explored. Weighted gene coexpression network analysis (WGCNA) is a newly emerged algorithm that can cluster genes and form modules based on similar gene expression patterns. This study constructed a gene coexpression network of IMPA via WGCNA and then carried out multifaceted analysis to identify novel disease-causing genes.MethodsRNA sequencing (RNA-seq) was performed for 10 pairs of IMPA and normal tissues to acquire the gene expression profiles. Differentially expressed genes (DEGs) were screened out with the cutoff criteria of |log2 Fold change (FC)|> 1 and adjusted p value < 0.05. Then, WGCNA was applied to systematically identify the hidden diagnostic hub genes of IMPA.ResultsIn this research, a total of 1970 DEGs were screened out in IMPA tissues, including 1056 upregulated DEGs and 914 downregulated DEGs. Functional enrichment analysis was performed for identified DEGs and revealed an enrichment of tumor-associated GO terms and KEGG pathways. We used WGCNA to identify gene module most relevant with the histological grade of IMPA. The gene FZD2 was then recognized as the hub gene of the selected module with the highest module membership (MM) value and intramodule connectivity in protein–protein interaction (PPI) network. According to immunohistochemistry (IHC) staining, the expression level of FZD2 was higher in low-grade IMPA than in high-grade IMPA.ConclusionFZD2 shows an expression dynamic that is negatively correlated with the clinical malignancy of IMPA and it plays a central role in the transcription network of IMPA. Thus, FZD2 serves as a promising histological indicator for the precise prediction of IMPA histological stages.

Comprehensive analysis of the transcriptome\u2010wide m6A methylome in invasive malignant pleomorphic adenoma

BackgroundInvasive malignant pleomorphic adenoma (IMPA) is a highly invasive parotid gland tumor and lacks effective therapy. N6-Methyladenosine (m6A) is the most prevalent post-transcriptional modification of mRNAs in eukaryotes and plays an important role in the pathogenesis of multiple tumors. However, the significance of m6A-modified mRNAs in IMPA has not been elucidated to date. Hence, in this study, we attempted to profile the effect of IMPA in terms of m6A methylation in mRNA.MethodsMethylated RNA immunoprecipitation with next-generation sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) were utilized to acquire the first transcriptome-wide profiling of the m6A methylome map in IMPA followed by bioinformatics analysis.ResultsIn this study, we obtained m6A methylation maps of IMPA samples and normal adjacent tissues through MeRIP-seq. In total, 25,490 m6A peaks associated with 13,735 genes were detected in the IMPA group, whereas 33,930 m6A peaks associated with 18,063 genes were detected in the control group. Peaks were primarily enriched within coding regions and near stop codons with AAACC and GGAC motifs. Moreover, functional enrichment analysis demonstrated that m6A-containing genes were significantly enriched in cancer and metabolism relevant pathways. Furthermore, we identified a relationship between the m6A methylome and the RNA transcriptome, indicating a mechanism by which m6A modulates gene expression.ConclusionsOur study is the first to provide comprehensive and transcriptome-wide profiles to determine the potential roles played by m6A methylation in IMPA. These results may open new avenues for in-depth research elucidating the m6A topology of IMPA and the molecular mechanisms governing the formation and progression of IMPA.

Role of overexpression of myeloid cell leukemia-1-long in prognosis of malignant pleomorphic adenoma

Objective: To evaluate the clinicopathological significance of the expression of the two myeloid cell leukemia-1 isoforms, myeloid cell leukemia-1-long (Mcl-1L) and myeloid cell leukemia-1-short (Mcl-1S) in malignant pleomorphic adenoma (MPA). Methods: A total of 56 patients with MPA treated with surgery, the expression of Mcl-1L and Mcl-1S were detected by quantitative real-time PCR (qPCR) in mRNA level, and by Western blotting in protein level, respectively. The correlation between clinicopathological parameters (gender, age, site, habits, size, node, metastasis, recurrence) was done using the chi-square test. Kaplan-Merier curve was used to analyze the survival in all patients, Log Rank test was performed to observe the difference between groups. Cox's proportional hazard test was used to identify the factors that were independent predictors of survival. Results: qPCR showed overexpression of Mcl-1L in 66.1%MPA patients (37/56), with significant difference in terms of tumor site, significantly higher expression of Mcl-1L in MPA (parotid gland: 2.21±1.07, sublingual gland: 2.12±1.08, other sites: 1.83±0.81) than benign pleomorphic adenoma tissue (1.00±0.19) (P<0.01). Western blotting analysis showed significantly higher expression of Mcl-1L in MPA (parotid gland: 1.02±0.43, sublingual gland: 0.71±0.29, other sites: 0.70±0.30) than benign pleomorphic adenoma tissue (0.39±0.08) (P<0.01). In malignant pleomorphic adenoma patients, high Mcl-1L expression was significantly associated with node positivity (P=0.045), advanced tumor size (P=0.002). Kaplan-Meier survival line analysis indicated a significantly lower survival time in Mcl-1L higher-expression patients (24.79±9.71) than lower-expression patients (30.59±9.01) (P=0.017). Multivariate analysis indicated Mcl-1L to be an independent prognostic factor for MPA (P=0.002). Conclusions: The studies suggest that overexpression of Mcl-1L is associated with poor prognosis in MPA. Mcl-1L is an independent prognostic factor in malignant pleomorphic adenoma.

A resected case of salivary gland-type malignant pleomorphic adenoma originating from the bronchus

A resected case of salivary gland-type malignant pleomorphic adenoma originating from the bronchus

Expression and significance of Bone Morphogenetic Protein 2 and phosphatase and tensin homolog deleted on chromosome ten in incipient, recurrent and malignant salivary gland pleomorphic adenoma

Objective To investigate the expression and significance of bone morphogenetic protein-2 (BMP-2) and phosphatase and tensin homolog deleted on chromosome ten (PTEN) in incipient, recurrent and malignant salivary gland pleomorphic adenoma. Methods A total of 93 cases of salivary gland pleomorphic adenoma in Kailuan general hospital from 2008 to 2017 were collected, including 54 in incipient group (group A, 47 cases in benign group A1, 7 cases in malignant group A2), 39 cases in recurrent group (group B, 26 cases in benign group B1, 13 cases in malignant group B2). The expression of BMP-2 and PTEN were detected by immunohistochemical detection and western blot, the correlation of BMP-2 and PTEN was analyzed by Spearman analysis. Results The immunohistochemical and western blot analysis both showed expression of BMP-2 in recurrent group was significantly higher than that in incipient cases((129.03±15.52) vs.(87.88±18.11), t=-8.094, P=0.000), and it was lower in malignant cases than that in benign cases((100.24±25.07) vs (116.66±26.19), t=2.125, P=0.040). There was no significant difference in PTEN expression between incipient and recurrent groups((89.15±13.92) vs.(96.19±28.02), t=1.055, P=0.279), but lower PTEN expression was found in malignant cases than benign cases((76.06±11.16) vs.(109.28±17.05), t=7.543, P=0.000). BMP-2 was positively correlated with PTEN expression (r=0.313, P<0.05). Conclusion BMP-2 is associated with the recurrence of salivary gland pleomorphic adenoma, and both BMP-2 and PTEN are associated with malignant in the salivary gland pleomorphic adenoma. Key words: Pleomorphic adenoma; Bone morphogenetic protein 2; Phosphatase and tensin homolog deleted on chromosome ten; Immunohistochemisty; Apoptosis

Differential diagnosis of different types of tumors in the parotid gland by 3.0T magnetic resonance dynamic enhanced imaging and diffusion-weighted imaging

Objective To investigate the differential diagnosis of benign and malignant parotid tumors by 3.0T MR dynamic enhancement (DCE-MRI) and diffusion-weighted MR imaging (DWI). Methods A retrospective analysis of 56 cases of parotid tumors in our hospital in May-2017 May 2016, and the integration of all patients with MRI and DWI data. The ADC value, the time signal intensity curve (TIC) and the quantitative parameters of the lesions were statistically analyzed, and the parameters of the diagnosis of malignant tumors were calculated by the receiver operating characteristic (ROC) curve. Results 86.67% (13/15) of pleomorphic adenoma in benign tumors showed A curve (Persistent), 13.23% (2/15) showed C curve (Washout), 73.07% (19/26) in adenolymphoma was B curve (Plateau), and the other 26.93% (9/26) was C type. In malignant tumor, 90% (9/10) presented a C curve and 10% (1/10) presented a B curve. The TIC types of benign and malignant parotid tumors were significantly different (P<0.05). There was a significant difference in ADC values between malignant tumors and pleomorphic adenoma, other benign tumors. Conclusion DCE-MRI and diffusion-weighted imaging have high clinical value in the differential diagnosis of benign and malignant tumors in the parotid gland, which may be useful for the diagnosis and treatment plan of parotid gland tumors. Key words: Parotid gland tumor; Dynamic enhancement; Quantitative analysis; Magnetic resonance imaging

Clinical analysis for the diagnosis and treatment of 25 cases with primary lacrimal gland epithelial tumor

Objective To explore the clinical manifestation, imaging features and treatment of primary lacrimal gland epithelial tumor. Methods The clinical data of 25 cases with primary lacrimal gland epithelial tumors were retrospectively studied. Results All of 25 primary lacrimal gland epithelial tumor cases received surgical treatment.Fourteen primary orbital tumors cases were male and 11 cases were female.The mean age was 44 years old (ranged 23 to 65). The mean hospital stay was 12d(ranged 7 to 20). Among 25 primary lacrimal gland epithelial tumor cases, 11 cases were benign tumors which included 4 inflammatory pseudotumor, 11 pleomorphic adenoma.Fourteen cases were malignant tumors which included 4 malignant pleomorphic adenoma, 6 adenoid cystic carcinoma and 4 adenocarcinoma.After opeation, visual acuity improved in 9 cases, unchanged 10 cases, decreased 6 cases.The patients were followed up for 16-48 months(mean 27 months). There were 4 malignant tumors recurrence after operation and received radical operation.While 2 patients were lost and 2 patients died of tumor metastasis, the other 21 patients survived with tumor-free. Conclusion Primary lacrimal gland epithelial tumors have different clinical and imaging appearances.Combination of ultrasound, CT and MRI is important to ascertain the character, range and degree of primary lacrimal gland epithelial tumors.Surgical excision is the main and effective treatment for primary lacrimal gland epithelial tumors, while gamma knife treatment is safe and effective for malignant, unresectable, recurrences tumors. Key words: Lacrimal gland tumor; Ophthalmology operation; Pathology, clinical

Maspin and MCM2 immunoprofiling in salivary gland carcinomas

BackgroundThe pathogenesis of salivary gland carcinomas is very complex and prognostic markers are difficult to find in these carcinomas of which the different subtypes have varying malignant potential. The study was conducted to examine the cellular distribution of maspin and MCM2 in salivary gland carcinomas and their value to predict lymph node metastasis.Materials and methodsFifty three paraffin blocks of different lesions (15 muco-epidermoid carcinoma, 14 adenoid cystic carcinoma, 3 epi-myoepithelial carcinoma, 5 salivary duct carcinoma, 5 malignant pleomorphic adenoma, 6 polymorphous low grade adenocarcinoma and 5 acinic cell carcinoma) were prepared for immunohistochemical staining with maspin and MCM2 antibodies. ANOVA and Pearson correlation tests were used for the statistical analysis of the results.ResultsAll salivary gland carcinomas express maspin and MCM2 with variable cellular localization. There was a significant difference in the expression of each antibody between mucoepidermoid carcinoma, adenoid cystic carcinoma and polymorphous low grade adenocarcinoma. No association was found between examined markers and lymph node metastasis.ConclusionsSalivary gland carcinomas express maspin and MCM2 with variable levels and cellular localization, consisting important markers of biological behavior in these tumors. The level of MCM2 expression can be used in the differential diagnosis of adenoid cystic carcinoma and polymorphous low grade adenocarcinoma. Further study with large sample size is recommended to assess their value in prediction of lymph node metastasis.

Malignant pleomorphic adenoma of salivary gland with subtype of the malignant component classified as non-specific adenocarcinoma: a clinicopathologic study of 65 cases

To analyze the clinicopathologic features of salivary malignant pleomorphic adenoma (MPA) (the subtype of the malignant component was classified as non-specific adenocarcinoma). The clinical and pathological characteristics of 115 salivary gland tumors histologically diagnosed as MPA were analyzed. In all the 65 MPA cases, there were 58 male and 7 female patients, and the mean age was 57 years (from 23 to 83). Sixty-one tumors were located in major salivary glands, and 4 in minor. Histologically the malignant components of 39 tumors were high-grade, 14 intermediate-grade, and 12 low-grade. Thirty-seven tumors were invasive carcinoma, 13 minimally invasive, and 15 non-invasive. The high-grade tumors had positive correlation with the invasive carcinomas (P < 0.05). The invasive carcinomas had positive correlation with TNM clinical stage (P < 0.05). The invasive carcinoma and the high-grade tumor had correlation with cervical lymph node metastasis (P < 0.05). Non-specific adenocarcinoma are the most common malignant subtype in MPA. The invasive and the high-grade types are more likely to metastasize to cervical lymph node.

Polymorphous Low Grade Adenocarcinoma: Literature Review and Report of Lower Lip Lesion with Suspected Lung Metastasis

Polymorphous low grade adenocarcinoma (PLGA) is an uncommon tumour that affects minor salivary glands mainly. It was known to be clinically benign and histologically polymorphic; sometimes misdiagnosed as pleomorphic adenomas, monomorphic adenomas, malignant pleomorphic adenomas, adenoid cystic carcinomas and adenocarcinoma not otherwise specified. More information about PLGA is cumulating in the current literature with new evidences suggesting that the tumour may not be as indolent as it was previously thought. A thorough understanding of the clinical and histological behaviour of the lesion has serious implications in management. Here, a case of lower lip lesion with suspected lung metastasis is reported to exemplify how the clinical behaviour of the lesion may affect management.

Ezrin and inducible nitric oxide synthase in malignant proliferation of salivary gland pleomorphic adenoma

Ezrin and inducible nitric oxide synthase (iNOS) may play an important role in regulating tumor proliferation, invasion, and metastasis. This study was to investigate the expression of Ezrin and iNOS and their correlation to malignant proliferation of salivary gland pleomorphic adenoma (PA). Expressions of Ezrin, iNOS and nuclear Ki-67 antigen were detected by immunohistochemistry in common type (n=40), active type (n=25) and malignant (n=11) pleomorphic adenoma. Expressions of Ezrin, iNOS in common type, active type and malignant pleomorphic adenoma were gradually increased (P<0.05). There was a significant positive correlation between the expression of Ezrin and iNOS (P<0.05). Ki-67 proliferation index (Ki-67 PI) was increased with the increasing of Ezrin and iNOS expressions (P<0.05). Overexpression of Ezrin and iNOS may promote proliferation and malignant transformation of salivary gland pleomorphic adenoma.

Metastasizing malignant pleomorphic adenoma in a young man

We present the case of a younger man with metastasizing carcinoma of unknown primary site, where autopsy revealed a malignant pleomorphic adenoma (MPA) of the submandibular gland. MPA is very rare in young persons.

副咽頭間隙腫瘍の検討

Tumors arising in the parapharyngeal space are rare. We reviewed 13 cases of parapharyngral space tumors that had been operated on between 1999 and 2004, and investigated the preoperative diagnosis, method of operation, and complications after surgery. Computed tomography, magnetic resonance imaging and fine-needle aspiration cytology were very useful for preoperative diagnosis, judging the extent of involvement and localization, and assessing the pathology of the tumor in the parapharyngeal space. The pathological diagnosis of these tumors was pleomorphic adenoma (6 cases), neurilemmoma (5 cases), ganglioneuroma (1 case), and malignant pleomorphic adenoma (1 case). The cervical approach was the most common, and was used in seven cases. Other surgical approaches included the cervical approach with mandibulotomy (2 cases), cervical-parotid approach (2 cases), and parotid approach (2 cases). First bite syndrome (FBS) has recently been reported as a complication after surgical removal of parapharyngeal space tumors. We experienced 4 cases of FBS. Since FBS was very difficult to treat in these patients, it is necessary to be aware of this syndrome.

PLAG1 gene alterations in salivary gland pleomorphic adenoma and carcinoma ex-pleomorphic adenoma: a combined study using chromosome banding, in situ hybridization and immunocytochemistry

Pleomorphic adenoma is the most common benign tumor of the salivary glands. It has marked histological diversity with epithelial, myoepithelial and mesenchymal-type cells arranged in a variety of architectural and differentiation patterns. Pleomorphic adenoma gene 1 (PLAG1), shown to be consistently rearranged in pleomorphic adenomas, is activated by chromosomal translocations involving 8q12, the chromosome region that is most frequently affected in these tumors. In this study, we evaluated PLAG1 involvement in salivary gland tumorigenesis by determining the frequency of its alterations in a selected group of 20 salivary gland tumors: 16 pleomorphic adenomas and four carcinomas ex-pleomorphic adenoma, having in common the presence of karyotypic chromosome 8 deviations, either structural, with 8q12 rearrangements, or numerical, with gain of chromosome 8. PLAG1 status was analyzed using in situ hybridization techniques, on metaphase cells, by fluorescence detection and/or interphase cells in paraffin sections, by chromogenic detection. Except for one pleomorphic adenoma case (5%) that lacked PLAG1 involvement, 17 tumors (85%), (14 pleomorphic adenomas and three carcinomas ex-pleomorphic adenoma) showed intragenic rearrangements of PLAG1 and the remaining two cases (10%), (one pleomorphic adenoma and one carcinoma ex-pleomorphic adenoma), had chromosome trisomy 8 only. To further investigate the role of PLAG1 on pleomorphic adenomas tumorigenesis, as well as the putative morphogenesis mechanism, we attempted to identify the cell types (epithelial vs myoepithelial) carrying 8q12/PLAG1 abnormalities by a combined phenotypic/genotypic analysis in four cases (three pleomorphic adenoma and one carcinoma ex-pleomorphic adenoma) characterized by 8q12 translocations and PLAG1 rearrangement. In these cases, both cells populations carried PLAG1 rearrangements. This finding further supports the pluripotent single-cell theory, which postulates that the tumor-initiated, modified myoepithelial cell, evolves into the varied somatic cell phenotypes present in pleomorphic adenoma, and reinforces the role of PLAG1 on the tumorigenesis of benign and malignant pleomorphic adenoma.

MR Findings of Nine Cases of Palatal Tumor

To assess the magnetic resonance imaging (MRI) findings of pathologically confirmed palatal tumors. Nine cases of palatal tumor were studied. Clinical data, MRI findings, and pathological diagnoses were evaluated. Five cases were tumors of the hard palate and four of the soft palate. Signal intensity on T1-weighted images varied, and hyperintensity was observed on T2-weighted images. Adenoid cystic carcinoma and diffuse large B cell lymphoma showed homogenous signal intensity. Other tumors showed heterogeneous signal intensities. On dynamic contrast analysis, malignant pleomorphic adenoma, adenoid cystic carcinoma, diffuse large B cell lymphoma, and peripheral T cell lymphoma showed early enhancement. On post-contrast T1-weighted images, hard palate pleomorphic adenoma, malignant pleomorphic adenoma, adenoid cystic carcinoma, diffuse large B cell lymphoma, and peripheral T cell lymphoma showed strong enhancement. Although the borders of the tumors were classified as clear in 6 cases treated surgically, macroscopic and microscopic borders of the tumors were unclear. Adenoid cystic carcinoma and hard palate diffuse large B cell lymphoma invaded the maxillary bone. Magnetic resonance findings of palatal tumor varied in different histologies. Even with a small palpable portion, malignant tumors could directly infiltrate surrounding structures, which demonstrated well on MRI.

Intraosseous myoepithelial neoplasms of the maxilla: Diagnostic and therapeutic considerations in 5 South African patients

J Oral Maxillofac Surg 61:379-386, 2003

"Malignant Pleomorphic Adenoma" in the Palate.

A case of tumor occurring in the palate of a 74-year-old Japanese female is reported. Although histological and immunohistochemical features of the tumor were identical to those of pleomorphic adenoma, except for scarce pleomorphic or “mixed” appearance, diffuse cellular and nuclear pleomorphism and relatively high proliferative cellular activity were observed. However, there was no metastasis or recurrence, indicative of its low-grade malignancy. Preexisting benign pleomorphic adenoma was not recognized. Due to these characteristics, we consider that the tumor should be diagnosed as “malignant pleomorphic adenoma” or “lowgrade malignant mixed tumor” and propose to separate such types of tumor from ordinary types of pleomorphic adenoma and carcinoma in pleomorphic adenoma.

当科における大唾液腺腫瘍の臨床統計

Seventy-three cases of major salivary gland tumors (36 males and 37 females) treated in our department between 1990 and 1996 were reviewed and analyzed clinically. These patients ranged in age from 19 to 86 years. There were 64 parotid gland tumors (88%) and 9 submandibular gland tumors (12%).The most prevalent tumor among the benign parotid gland tumors was pleomorphic adenoma (47.2%), followed by Warthin's tumor (28.3%). Malignant tumors consisted of three malignant pleomorphic adenomas, two mucoepidermoid carcinomas, two adenocarcinomas, two salivary duct carcinomas, one adenoid cystic carcinoma and one malignant lymphoma. Surgery alone was performed for all the benign tumors. For the malignant tumors, combined treatment with surgery, irradiation and anticancer drugs was performed. Facial nerve palsy, salivary fistula or Frey's syndrome occurred in some patients after surgery. Only one of the benign tumors recurred. All patients with stage I or II disease are alive, but most of the patients with stage III and IV disease died within three years.

多形性腺腫およびその悪性型（悪性多形性腺腫，多形性腺腫内癌）の臨床的特徴の比較検討

Pleomorphic adenoma is the most common tumor of the salivary gland. Usually, it grows slowly and has a good prognosis. However, some pleomorphic adenoma. generally referred to as malignant pleomorphic adenoma (carcinoma in pleomorphic adenoma) show invasive growth or distant metastasis. We examined clinical features in 69 patients who were given a diagnosis and treated at our clinic during the past 16 years. The 69 patients included 63 patients with pleomorphic adenoma and 6 patients with malignant pleomorphic adenoma. The 63 cases of pleomorphic adenoma occurred in 21 males and 42 females. The ratio of males to females was 1: 2, indicating a higher prevalence in females than males. The 6 cases of malignant pleomorphic adenoma occurred in 4 males and 2 females. The diagnosis was carcinoma in pleomorphic adenoma in 4 cases and so-calld malignant pleomorphic adenoma in the other 2 cases. Five of these patients were treated at our clinic; surgery was performed in all 5 patients. The 5 -year survial rate was 80%.