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.

Pleomorphic adenoma with extensive squamous and mucinous metaplasia and a novel MALAT1::PLAG1 fusion gene

Cases of metaplastic pleomorphic adenoma can be diagnostically challenging. Many of these cases fall into the Milan system's SUMP category, and some may be misdiagnosed. The author shows a case of pleomorphic adenoma with extensive squamous and mucinous metaplasia and a novel MALAT1::PLAG1 fusion.

Clinical behavior of recurrent pleomorphic adenoma in the palate: a systematic review

PURPOSE

This systematic review analyzed the clinical behavior and odds of malignancy of the palatal recurrent pleomorphic adenomas.

METHODS

Systematic review of patients with recurrent pleomorphic adenoma arising in the palate. Database search: MEDLINE, Scopus, Web of Science, Cochrane, EMBASE, Virtual Health Library, Google Scholar, and OpenGrey. A binomial logistic regression was performed to assess the odds of detecting recurrence five, 10 and 20 years after the treatment of primary tumor.

RESULTS

Thirteen studies (n = 18 patients) out of 336 were included. The recurrent pleomorphic adenoma in palate was more common in females (61.6%), average age was 49 years old (range 9-73 years old). Four patients progressed to malignant transformation. The odds ratio (OR) of detecting a recurrence at 10 (OR = 5.57; 95% confidence interval - 95%CI 1.13-27.52), and 20 years (OR = 18.78; 95%CI 3.18-110.84) after treatment of primary pleomorphic adenoma was significantly higher than at one-year follow-up.

CONCLUSIONS

The recurrence of pleomorphic adenoma in palate remains a rare event of late occurrence. It mainly affects middle-aged female and carries a risk of malignant transformation. Although uncommon, patients with palatal pleomorphic adenoma should be warned about the possibility of recurrence or malignant transformation of tumor at advanced ages.

A Large Pleomorphic Adenoma in Nasal Cavity Misdiagnosed as Inverted Papilloma

Pleomorphic adenoma (PA) is a benign tumor characterized by slow-growing mixed tumors in the craniofacial area. It is relatively common in salivary glands; however, PA of the nasal cavity, which arises in the minor salivary glands, is rare. We present the case of a large PA in the nasal cavity of an adult immunocompetent woman with nasal obstruction and intermittent epistaxis. Based on preoperative radiologic examinations, she was misdiagnosed with an inverted papilloma. Endoscopic resection was performed under general anesthesia. Pathologically, the patient was confirmed to have PA, which has great cellularity and few stromal components. No complications or recurrences during the 1-year follow-up period were observed.

Chondroid Syringoma on the Tip of the Nose: A Case Report

ABSTRACT

Chondroid syringoma is a benign, rare, asymptomatic, slow-growing mixed tumor. The authors present the case of a 17-year-old adolescent boy who had a tumor on the tip of his nose for a duration of 8 months. An excisional biopsy was performed under local anesthesia. Based on histopathologic analysis, the resected lesion was identified as a chondroid syringoma.

Analysis of clinical features of 7 cases of primary pleomorphic adenoma of lower respiratory tract and review of literature

To investigate the clinical characteristics of patients with primary pleomorphic adenoma of the lower respiratory tract. The clinical manifestations, laboratory results, pathological and imaging, treatment and prognosis of 7 patients with primary pleomorphic adenoma of the lower respiratory tract who were treated in Hunan Provincial People's Hospital from December 2015 to May 2020 were analyzed. Among the 7 patients, 5 patients had cough and expectoration as the main clinical manifestations, and the other 2 patients had no symptoms. Pleomorphic adenomas of the lower respiratory tract are mostly located in the trachea or bronchus, and the chest computed tomography findings are circular or ellipsoid masses, or flake high-density shadows and local thickening of the tracheobronchial wall. Tumor histological features and immunohistochemistry can diagnose pleomorphic adenoma and its origin. In this study, 2 asymptomatic patients refused further treatment, 1 survived for more than 3 years, and the other was lost to follow-up during follow-up. One patient with surgical resection was followed up for 5 years after surgery and had a good survival status. The other 4 patients with respiratory symptoms who could not undergo surgery were mainly treated with bronchoscopic interventional therapy on demand, and the survival time up to now was 2 to 5 years. Primary pleomorphic adenoma of the lower respiratory tract is rare in clinic. Its clinical symptoms are related to the location and size of the tumor. Both surgical resection and bronchoscopic intervention have a good clinical prognosis. The cause of death of patients with such diseases is mostly dyspnea caused by tumors in the airway. Early diagnosis, timely intervention and regular follow-up can make patients obtain better curative effect.

Updated Salivary Gland Immunohistochemistry: A Review

CONTEXT.—

Salivary gland neoplasms are rare lesions in the head and neck (H&N) pathology realm. There are more than 20 malignant and 15 benign salivary gland neoplasms in the 5th edition of the World Health Organization classification of H&N tumors. These neoplasms consist of heterogeneous groups of uncommon diseases that make diagnosis and treatment challenging for the clinical team. Using an algorithmic immunohistochemical approach-defined tumor origin and type has proven to be effective and advantageous. Immunohistochemistry may be used as sort of a "diagnostic looking glass," not as a positive or negative type tool, but as an indispensable complement to a hematoxylin-eosin morphologic pattern-based approach. Furthermore, the understanding of the novel discoveries of the salivary gland gene fusions and the molecular aspects of these tumors makes the process easier and improve the diagnosis as well as treatment aspects. This review reflects our experience with more recent diagnostic antibodies, which include MYB RNA, Pan-TRK, PLAG1, LEF1, and NR4A3. Each of these is linked with a specific type of neoplasm; for example, gene fusions involving the PLAG1 and HMGA2 oncogenes are specific for benign pleomorphic adenomas, and MYB is associated with adenoid cystic carcinoma.

OBJECTIVE.—

To review these more recent antibodies, which highly enhance salivary gland neoplasm diagnosis.

DATA SOURCES.—

The study sources involved literature PubMed searches, including multiple review articles, case reports, selected book chapters, and Geisinger Medical Center cases.

CONCLUSIONS.—

Salivary gland tumors are a rare, varied group of lesions in H&N pathology. We need to have continuous readings and revisions of the molecular consequences of these fusion oncoproteins and their subsequent targets, which will eventually lead to the identification of novel driver genes in salivary gland neoplasms.

Hyaline cell-rich chondroid syringoma: A potential pitfall on cytology

Chondroid syringoma is a rare adnexal tumor of skin, with few cases diagnosed on fine needle aspiration cytology (FNAC). Hyaline cell-rich chondroid syringoma (HCRCS) is a very uncommon variant of chondroid syringoma described in histopathologic studies. This variant differs from the usual chondroid syringoma in its site of presentation, cytohistologic features, and morphologically mimics malignant neoplasms. To the best of our knowledge, cytologic features of this entity have never been described. This case report highlights some unusual features of this tumor and discusses the cytologic features of HCRCS along with neoplastic mimics.

Clinicopathological characteristics of pleomorphic adenoma from the labial gland: A 20-year experience with 173 cases in one single institution

OBJECTIVE

Pleomorphic adenoma (PA) of the lip is not a common phenomenon, and existing literature provides limited information on the clinicopathological features of labial PA.

STUDY DESIGN

Patients diagnosed with labial PA at our single institution over the past 20 years (2001-2020) was retrospectively screened and analyzed to investigate the epidemiologic and clinicopathological features of these tumors.

RESULTS

A total of 173 cases were screened out, and the average age was 44.3 (range 7-82) years, with a peak incidence rate during the third decade. A slight predilection for men (52%) was observed, and PA occurs more frequently in the upper lip than in the lower lip, with a ratio of 14.7:1. On clinical examination, labial PAs usually present as painless masses that develop slowly with no systemic symptoms. Histologically, labial PAs contain myoepithelial and polygonal epithelial cells in myxoid, hyaline, fibrous, chondroid, and even osseous tissues, similar to those in other sites. Specifically, 15 of 173 patients with labial PA presented with cutaneous PA.

CONCLUSION

Labial PA presents over a wide age range and dominantly occurs at the upper lip. Surgical resection is the major treatment strategy, and postoperative recurrence or malignant transformation of labial PA was extremely rare.

Cytopathology of salivary gland myoepithelial carcinoma: A study of 13 cases and review of the literature

INTRODUCTION

Myoepithelial carcinoma (MECA) is an infrequently recognized salivary gland (SG) neoplasm that commonly develops within a preexisting pleomorphic adenoma (MECA ex PA). Fine-needle aspiration (FNA) biopsy reports of this neoplasm are largely restricted to small series and single case reports.

METHODS

Our cytopathology files were searched for examples of SG MECA/MECA ex PA having confirmatory histopathologic verification. Conventional FNA biopsy smears were performed, and exfoliative specimens processed using standard techniques.

RESULTS

Thirteen cases from 9 patients (M:F = 3.5:1; age range: 36 to 95 years, mean age = 60 years) met inclusion criteria. FNA biopsy sites included parotid gland (4), trunk (2), scalp (2), and neck (2). Exfoliative specimens included pleural fluid (1), bronchial brushing (1), and bronchoalveolar lavage (1). Most cases were metastatic deposits (8; 62%), 4 were primary neoplasms, and 1 a local recurrence. FNA diagnoses were MECA ex PA (6; 46%), myoepithelial neoplasm (2), PA (2), basaloid neoplasm (1), atypical myoepithelial cells (1), and myxoma (1). Ancillary testing in 2 cases showed positive staining for myoepithelial markers. Cytologic features were that of a low-grade neoplasm composed principally of epithelioid/polygonal cells exhibiting minimal if any cytologic atypia. Myxoid and chondromyxoid stroma was often the dominant feature in MECA ex PA aspirates.

CONCLUSION

In the primary setting, a cytologic diagnosis of MECA/MECA ex PA is extremely challenging if at all possible. Due to overwhelming amounts of stroma, the diagnosis may be challenging in some cases of metastatic MECA ex PA.

A challenging diagnosis of mammary analogue secretory carcinoma (MASC) on fine needle aspiration cytology and cell block: A cytopathologist's perspective

Mammary analogue secretory carcinoma (MASC) is a recently described salivary gland carcinoma that resembles the secretory carcinoma of the breast and is characterised by t(12;15) (q13;q25) translocation, which results in an ETV6-NTRK3 gene fusion product. On cytomorphology, it is characterised by papillary fragments, clusters, and singly dispersed tumour cells. These tumour cells are large and have abundant vacuolated cytoplasm. Acinic cell carcinoma of the salivary gland is the most common differential diagnosis of MASC. Other differentials include mucoepidermoid carcinoma, salivary duct carcinoma, pleomorphic adenoma, and oncocytic salivary gland neoplasms. Immunohistochemistry and morphology are critical in establishing the correct diagnosis. We present a case of a 46-year-old male patient diagnosed as MASC of the parotid gland on fine needle aspiration cytology and cell block.

Chondroid syringoma of an upper eyelid tumor: Unusual case report

We present the case report of a 58-year-old man with recurrent chondroid syringoma, which was histopathologically confirmed, who underwent exenteration surgery of the right eye. Furthermore, the patient was receiving postoperative radiation therapy, and presently there is no local and/or distant evidence of disease in the patient.

Pleomorphic adenoma of the tongue: A case report

RATIONALE

Salivary gland tumors account for approximately 3% of all tumors, most of which are benign, with pleomorphic adenomas being the most common, occurring mostly in middle-aged women, mostly originating from the major salivary glands and, to a lesser extent, from the minor salivary glands, with the tongue being a very rare site of occurrence. To date, case reports of pleomorphic adenoma at the root of the tongue are also rare.

PATIENT CONCERNS

A 56-year-old male patient with no obvious cause of foreign body sensation in the pharynx, sputum, no pain, no blood in the sputum, no dysphagia, and no difficulty in swallowing and breathing, which was significantly aggravated in the past 2 weeks, with difficulty in swallowing, breath-holding on lying down.

DIAGNOSES

computed tomography and magnetic resonance imaging revealed a soft tissue mass at the root of the left tongue, which involved the tongue body in the forward direction. Electronic laryngopharyngoscopy showed a left-sided tongue root mass with a poorly smooth mucosa, covered with a mucous white pseudomembrane and a localized brownish-black crust without active bleeding. The final pathological findings showed a pleomorphic adenoma.

INTERVENTIONS

Postoperative symptomatic treatment was given, and the patient recovered well. Eight days after surgery, the patient was discharged from the hospital, and the pharyngeal pain basically subsided at the time of discharge, with no fever and no pharyngeal discomfort. Postoperative laryngoscopy showed smooth mucosa of the pharyngeal cavity, good pseudomembrane formation in the operated area, no active bleeding, no purulent secretions, and normal blood routine on recheck. The medical advice after discharge was firstly, full rest for 1 week, secondly, continue the oral anti-inflammatory treatment, 1 week after the operation need to review the outpatient clinic, finally, if there are any uncomfortable symptoms, seek medical attention in time.

OUTCOMES

At present, the patient has been followed up for half a year and has recovered well from the operation without any discomfort.

LESSONS

It is very rare to find a pleomorphic adenoma of the tongue, and it occurs mostly in middle-aged women. In clinical diagnosis, it is sometimes difficult to distinguish it from malignant tumor of the tongue.

A 10-Year Review of Intraoral Salivary Gland Tumor Diagnoses: Diagnostic Challenges and Inter-Observer Agreement

BACKGROUND

Salivary gland tumors (SGT) are a diverse group of neoplasms arising from the major and minor glands. The oral cavity is the most common site for minor SGT (IMSGT), and these lesions frequently pose a challenge to the pathologist due to overlapping histopathological features and limited material for analysis. Our objective was to determine specific clinical and histopathological features associated with challenges in IMSGT diagnoses and pathologists' agreement.

METHODS

We conducted a retrospective analysis of 248 IMSGT received between 2010 and 2019. We evaluated the diagnostic challenge of the cases by stratifying according to whether a definitive, favored, or indeterminate (challenging) diagnosis was provided. Inter-observer agreement and concordance of biopsy diagnoses with the final diagnoses after tumor resection were evaluated.

RESULTS

Of the 248 biopsies, 191 had a definitive diagnosis, 38 favored diagnoses, and 19 were indeterminate. The predominant diagnoses considered for the indeterminate category were pleomorphic adenoma/myoepithelioma (PA), polymorphous adenocarcinoma (PAC), adenoid cystic carcinoma (AdCC), and low-grade adenocarcinoma. Using multivariate analysis of clinical features, younger patient age, smaller tumor size, and larger biopsy size increased the likelihood of a definitive diagnosis (p = 0.014, p = 0.037, p = 0.012). The inter-observer agreement for 68 representative cases was moderate overall (Fleiss's Kappa 0.575) and good for the 40 cases with a definitive diagnosis (Fleiss's Kappa 0.66). Sixty-five biopsy diagnoses were matched with corresponding tumor resection diagnoses and found to show a good concordance (Cramer's V test 0.76). The discordant diagnoses predominantly involved PA, carcinoma exPA, PAC, AdCC, and adenocarcinoma NOS.

CONCLUSION

Diagnostic challenges in IMSGT incisional biopsies were infrequent, especially if multiple pathologists were consulted. PA, PAC, AdCC, and adenocarcinoma NOS were the histologic types more commonly posing diagnostic challenges. Younger patient age, smaller tumor size, and larger biopsy are associated with a definitive diagnosis. This data highlights the importance of appropriate sampling in IMSGT.

Mucoepidermoid Carcinoma Ex Pleomorphic Adenoma of Lacrimal Gland: Case Report and Review of Literature

Carcinoma ex pleomorphic adenoma (Ca ex PA) is defined as an infiltrative carcinoma arising from a primary or recurrent benign pleomorphic adenoma. Ca ex PA with the histologic subtype mucoepidermoid carcinoma is extremely uncommon. Only 2 previous reports in the lacrimal gland have been documented. We reported a 55-year-old lady with a firm, solid, nontender mass in the supralateral quadrant of the right orbit at the area of the lacrimal gland. After wide excision of mass, pathology revealed high-grade mucoepidermoid carcinoma Ex pleomorphic adenoma. To reduce tumor recurrence 60 Gray radiation was delivered to the orbital cavity. She is still tumor-free 1 year after completion of treatment.

Risk and Lag-time for Development of Lacrimal Gland Carcinoma Expleomorphic Adenoma: Observations and Conjectural Study

AIMS

To estimate the proportion of de novo lacrimal gland pleomorphic adenomas (PAs) and carcinomas expleomorphic adenomas (CEPAs), together with age at presentation and first symptom. Conjectural models of tumor growth are considered.

METHODS

Retrospective review of patients with orbital lobe PA or CEPA. The presenting age was examined for conformation to a Gaussian distribution and the cumulative distribution function derived for both tumor types. The risk of CEPA with age was estimated by logistic regression.

RESULTS

About one-sixth (27/172; 16%) of these primary orbital lobe tumors were CEPAs, with 145 PAs (76/145 male; 52%) and 27 CEPAs (12/27 male; 44%). The mean presenting age for PAs was 48.3 years (median 47.7; range 11-84 years) and 57.7 years for CEPAs (median 61.2, range 27-91 years) ( p = 0.0062), and the standard deviations for each group are almost identical (16.3 for PAs, 15.9 for CEPAs; p = 0.92). Five (3.4%) PAs and 1 (3.7%) CEPA were asymptomatic: otherwise, the median symptom duration was 24 months for both PAs and CEPAs ( U test: p = 0.65). The odds of CEPA rises significantly with age, increasing 1.04-fold annually ( p = 0.0079).

CONCLUSION

The almost identical measures of dispersion for the presenting ages of PA and CEPA suggests that, once malignant transformation occurs, there might be a relatively constant period before it is evident. CEPAs present about a decade after PAs, this unexpectedly later presentation for the malignancy possibly being explained by a gradual replacement of the PA by the newly arising carcinoma within the preceding benign tumor.

Cystic Salivary Gland Neoplasms: Diagnostic Approach With a Focus on Ancillary Studies

Cystic salivary gland cytology can be challenging due to the fact that a cystic mass can be the clinical presentation of both non-neoplastic and neoplastic conditions. Neoplastic lesions consist of both benign and malignant neoplasms. The cytomorphologic features of these entities can overlap and the cystic background may additionally contribute to the complexity of these lesions and their interpretation. Ancillary studies have been reported in several studies to be beneficial in further characterization of the cellular components and subsequent diagnosis of the cystic lesions of the salivary gland. Fluorescence in situ hybridization, real-time polymerase chain reaction, and next-generation sequencing are now being utilized to detect molecular alterations in salivary gland neoplasms. MALM2 rearrangement is the most common gene fusion in mucoepidermoid carcinoma. PLAG1 rearrangement is present in more than half of pleomorphic adenomas. AKT1:E17K mutation is the key diagnostic feature of the mucinous adenocarcinoma. NR4A3 overexpression is highly sensitive and specific for the diagnosis of acinic cell carcinoma. MYB fusion is noted in adenoid cystic carcinoma. ETV6:NTRK3 fusion is helpful in diagnosis of secretory carcinoma. p16 and human papillomavirus (HPV) studies differentiate HPV-related squamous cell carcinoma from non-HPV-related neoplasms with overlapping features. NCOA4:RET fusion protein is the main fusion in intraductal carcinoma.

Pleomorphic Adenoma of Minor Salivary Gland

Pleomorphic adenoma is a benign tumor of salivary glands, arising from minor salivary glands, is very rare and presents with a minor female predilection; and the highest occurrence is between the fourth and sixth decades of life. It is of glandular origin, usually presenting as a slowly growing, painless, firm swelling that does not cause ulceration of the overlying mucosa. In this case, a 27-year male presented with swelling on buccal mucosa for three years. The swelling was firm and well circumscribed. Excisional biopsy was done under general anesthesia and the mass was excised. The histopathological evaluation revealed pleomorphic adenoma. This case highlights the need to keep this entity in the differential diagnosis of intra-oral indolent swellings of some duration. Key Words: Pleomorphic adenoma, Buccal mucosa, Minor salivary glands.

The evolving role of molecular pathology in the diagnosis of salivary gland tumours with potential pitfalls

Salivary gland tumors are diagnostically challenging owing to the morphological diversity within any tumor type and overlapping histomorphology and immunohistochemistry amongst different tumours. In past two decades, rapid progress has been made in the field of understanding the pathogenesis of these tumours with the discovery of many tumour specific translocations and rearrangements. This includes CRTC1-MAML2 and CRTC-MAML2 in mucoepidermoid carcinoma, MYBNFIB and MYBL1-NFIB fusions in adenoid cystic carcinoma, PLAG1 and HMGA2 in pleomorphic adenoma, ETV6-NTRK3 in secretory carcinoma, NR4A3 rearrangements in acinic cell carcinoma, PRKD1 mutations in polymorphous adenocarcinoma and EWSR1-ATF1 in clear cell carcinoma. This review is a lens for progress made till date in the molecular pathology of salivary gland tumours with a special focus on their role as diagnostic tools and implications on clinical management of the patient as prognostic and predictive markers.

Chronic Granulomatous Dacryoadenitis Associated With Pleomorphic Adenoma

Chronic granulomatous inflammation occurs rarely alongside pleomorphic adenomas of the major salivary glands but would not appear to have been reported with lacrimal gland adenomas. We describe the clinical features, imaging and histopathology for 4 patients (3 female) who had granulomatous inflammation alongside lacrimal gland adenomas-the patients being with age 39, 44, 48, and 53 years at time of surgery. One patient had an asymptomatic lesion found on imaging, and the other 3 had symptoms for between 3 years and several decades. Conjecturally, this rare phenomenon might arise from an inflammatory response to leakage of secretions from the ductular components of the glands.

Pleomorphic adenoma: Detection of PLAG1 rearrangement-positive tumor components using whole-slide fluorescence in situ hybridization

AIM

Pleomorphic adenoma (PA) consists of heterogeneous histological architecture mixed with epithelioid and mesenchymal forms. Various types of epithelial or myoepithelial malignancies arise from PA, but sarcomas are extremely rare. A HUMARA clonality assay has suggested that PA is clonal in nature. However, clonality of various tumor components of PA would be difficult to determine with this assay. In addition, the results obtained should be carefully interpreted. PLAG1 rearrangements are considered a good molecular marker for neoplasticity in PA. We aimed to clarify the neoplasticity of the various tumor components present in PA using whole-slide fluorescence in situ hybridization (FISH).

METHODS

Five PA cases positive for PLAG1 rearrangements were examined. Using an immunohistochemistry panel, cell components in PA were classified into eight cell types. To precisely localize PLAG1 rearrangement-positive cell components at the cellular level, sequential retrieval of whole-slide imaging (WSI) data of HE histology and FISH for PLAG1 rearrangement was carried out.

RESULTS

PLAG1 rearrangements were detected in ductal cells, myoepithelial spindle cells, myoepithelial oncocytic cells, myoepithelial plasmacytoid cells, and mesenchymal chondroid cells, but not in mesenchymal lipid cells, mesenchymal fibrous cells, or vascular endothelial cells. Immunohistochemical PLAG1 expression was restricted to cell components harboring PLAG1 rearrangements.

CONCLUSIONS

The results of the present study indicate that ductal and myoepithelial, chondroid cells are neoplastic but lipid, fibrous, and endothelial cells are not. PLAG1 immunohistochemistry is useful in discriminating neoplastic from non-neoplastic cell components. These findings may be important for elucidating tumorigenesis and the process of malignant transformation in PA.

Cytopathology of solitary fibrous tumor: a series of 34 cases

INTRODUCTION

Solitary fibrous tumor (SFT), a fibroblastic neoplasm characterized by a specific genetic alteration (NAB2-STAT6 fusion) and relatively specific immunohistochemical profile (STAT6/CD34 positivity), is seldom the subject of cytopathology data. We report our experience with scrape smears and fine-needle aspiration (FNA) biopsies of SFT in a large patient cohort.

MATERIALS AND METHODS

A search was made of our cytopathology and surgical pathology databases for cases diagnosed as solitary fibrous tumor (SFT). FNA biopsy smears, imprint smears, and cell blocks were performed and examined using standard technique.

RESULTS

Thirty-four cases from 30 patients (M:F = 1.1:1; age range: 24-86 years, x = 58 years) met inclusion criteria for this study. All patients had prior or subsequent tissue confirmation of SFT. Twenty-seven (79%) specimens were FNAs, and 7 (21%) were scrape smears. Most cases (29, 85%) represented primary tumors, 4 (12%) were metastatic deposits, and 1 (3.5%) was a locally recurrent neoplasm. Sites included: pleura/lung 9 (26%), head/neck 8 (24%), lower extremity 7 (21%), trunk 4 (12%), intra-abdominal 3 (9%), upper extremity 2 (7%), and mediastinum 1 (4%). Mean tumor size was 7.2 cm (range: 1.5-19 cm). Three (9%) cases were diagnosed specifically as SFT. Remaining diagnoses were spindle cell neoplasm/proliferation 14 (41%), nondiagnostic 5 (15%), specific type of sarcoma 3 (9%), malignant round cell tumor 2 (6%), sarcoma 2 (6%), malignant tumor 2 (6%) and single cases of melanoma, pleomorphic adenoma, and mesenchymal tumor. Immunohistochemical (IHC) testing was performed in 7 of 27 (26%) cell blocks.

CONCLUSION

SFT FNA cytopathology is morphologically ambiguous, overlapping with a broad array of other spindle cell proliferations. A specific diagnosis is only possible with added staining of STAT6 coupled with a set of other IHC markers.

Myoepithelial Carcinoma

Myoepithelial carcinoma (MECA) may overlap histologically with other salivary gland neoplasms, especially pleomorphic adenoma. MECA is characterized by cellular, uniform growth of myoepithelial cells and multinodular expansile invasive pattern with zonal cellular distribution. It may arise de novo or in association with pleomorphic adenoma (myoepithelial carcinoma ex pleomorphic adenoma). By immunohistochemistry, MECA is positive for cytokeratins and at least one of the myoepithelial markers, including S100. PLAG1 fusion is the most common genetic alteration. Carcinoma ex pleomorphic adenoma and necrosis correlate with worse clinical outcome in MECA, and necrosis can be used to stratify MECA as high grade.

Basal Cell Adenoma of the Parotid Gland

Basal Cell Adenoma (BCA) known as monomorphic adenoma is a rare type of benign epithelial salivary neoplasm that mostly occurs in the parotid gland. Clinically BCA appears as a firm, mobile, slow-growing mass and is usually diagnosed during the histopathological examination of the resected surgical specimen. Histological differential diagnosis ranges from benign to malignant neoplasms such as pleomorphic adenoma, basal cell adenocarcinoma, adenoid cystic carcinoma and basaloid squamous cell carcinoma. The treatment of BCA is surgical excision, due to its varied prognosis with the different histological subtypes; a regular long term follow up of the patient postoperatively is mandatory. We report a rare and interesting case of basal cell adenoma of the parotid gland in a 52 year old female. We review the literature; discuss the diagnosis and management of this rare histological entity.

[Correlation between magnetic resonance imaging and extemporaneous and definitive histological examination of parotid gland tumors: a case series]

Parotid gland tumor is complex and poses diagnostic and therapeutic problems. The purpose of this study was to assess the role of extemporaneous examination in the management of patients with parotid gland tumors. We report a pro and retrospective analytical study of a series of cases of salivary gland tumors, whose data were collected in the ENT and in the department of cervical-facial Surgery at the University Hospital in Casablanca, between January 2012 and December 2015. Seventy two cases of parotid tumors were recorded. The sex-ratio (H/F) was 0.94, 0.76 for patients with benign tumors and 1.62 for patients with malignant tumors. The average age was 47 years (15- 75 years). The median of consultation time was 40 months. Clinical symptoms were dominated by parotid swelling (100%), pain in 25% of patients, facial palsy in 6%, and cervical adenopathies in 10%. Ultrasound was recommended in 80% of patients. MRI was performed in 26% of cases. All patients underwent surgery, 76% of patients underwent exofacial parotidectomies and 24% total conservative parotidectomies. This treatment was associated with ganglion resection in 24% of cases and radiotherapy in 24% of cases. Extemporaneous examination was performed in 71% of patients, its susceptibility was 89% and its specificity 88%. Definitive histological diagnosis was confirmed by anatomopathological examination in all cases. We confirmed benign and malignant tumors in 71% and 29% of cases respectively. Benign tumors were dominated by pleomorphic adenoma (59%), while malignant lesions were dominated by mucoepidermoid carcinoma (38%). The postoperative course was marked by: discrete haematoma in 4% of cases, transient facial palsy in 15%, superinfection of the wound in 3% and post-parotidectomy Frey´s syndrome in 3% of patients. One patient had labial recurrence of acinar cell carcinoma. No cases of death were noted. Parotid gland tumors are characterized by a great histological variability. Differentiation between malignant tumor and benign tumor is often difficult. Currently, MRI is the imaging test of choice. Extemporaneous examinationis is very useful intraoperatively when it is necessary to communicate with the pathologist. Multidisciplinary approach is adopted including ENT, oncological, radiotherapeutic, pathological and radiological approaches. Prognosis depends on the histological type, the stage of progression and treatment.

Epithelial-myoepithelial carcinoma ex-pleomorphic adenoma of the parotid gland: report of a rare case with immunohistochemical and genetic analyses

Epithelial-myoepithelial carcinoma (EMCa) is a rare low-grade salivary malignancy. It is rare for EMCa to occur as the carcinomatous component of carcinoma ex-pleomorphic adenoma (PA). We examined one additional case of EMCa ex-PA, immunohistochemically and genetically. The patient was an 83-year-old female, who suffered from swelling of the right parotid region. Histologically, the tumor contained a hyalinized nodule, which displayed elastosis. The main tumor exhibited a bi-layered structure, involving inner ductal cells and clear outer myoepithelial cells. Immunostaining indicated that the inner cells were positive for epithelial membrane antigen, whereas the outer cells were positive for p40. On the genetic level, the carcinoma harbored no HRAS gene mutations, whereas fluorescence in situ hybridization (FISH) of the Pleomorphic Adenoma Gene1 showed splitting signals in the carcinomatous component. We diagnosed this case as EMCa ex-PA. It is necessary to differentiate EMCa ex-PA from myoepithelial carcinoma and clear cell carcinoma, and FISH is useful for such purposes.

Molecular profile of a pleomorphic adenoma of the hard palate: A case report

RATIONALE

Pleomorphic adenoma (PA) is the most common benign tumor of salivary glands. PAs have the potential for regional and distant metastases that preserve their benign phenotype; they also have the potential for malignant transformation. The molecular pathogenesis of malignant neoplasms has been studied extensively in recent years, unlike that of benign tumors, such as PA.

PATIENT CONCERNS

In this case report, we identified the molecular signatures of a 57-year-old Japanese woman. Our patient presented with a swelling of the hard palate with an erosive appearance.

DIAGNOSES

The patient was diagnosed with a right hard palate tumor suspected to be a malignant neoplasm.

INTERVENTIONS

Partial maxillary resection and reconstruction were performed.

OUTCOMES

There was no obstacle to swallowing or dysarthria after surgery. There was no sign of recurrent palatal tumor 4 years after the operation. Using next generation sequencing, 5 nonsynonymous mutations and CHCHD7-PLAG1 fusion genes were detected. Moreover, gene expression profiling indicated the possibility of the activation of several cancer-related signaling pathways. Although the PLAG1 gene is predicted to play a crucial role in PA tumorigenesis, its over-expression is reported to mediate multiple downstream factors. In this case, various up- and downregulated RNA signaling pathways, including MAP kinase signaling, PI3K/AKT1/MTOR signaling, JAK/STAT signaling, and PD-L1 signaling, were revealed.

LESSONS

These molecular profiles of PA may elucidate the mechanism of metastasis, preserving its benign phenotype and carcinoma ex PA.

Imaging quality of PROPELLER diffusion-weighted MR imaging and its diagnostic performance in distinguishing pleomorphic adenomas from Warthin tumors of the parotid gland

The aim of this study was to evaluate the imaging quality and diagnostic performance of fast spin echo diffusion-weighted imaging with periodically rotated overlapping parallel lines with enhanced reconstruction (FSE-PROP-DWI) in distinguishing parotid pleomorphic adenoma (PMA) from Warthin tumor (WT). This retrospective study enrolled 44 parotid gland tumors from 34 patients, including 15 PMAs and 29 WTs with waived written informed consent. All participants underwent 1.5 T diffusion-weighted imaging including FSE-PROP-DWI and single-shot echo-planar diffusion-weighted imaging (SS-EP-DWI). After imaging resizing and registration among T2WI, FSE-PROP-DWI and SS-EP-DWI, imaging distortion was quantitatively analyzed by using the Dice coefficient. Signal-to-noise ratio and contrast-to-noise ratio were qualitatively evaluated. The mean apparent diffusion coefficient (ADC) of parotid gland tumors was calculated. Wilcoxon signed-rank test was used for paired comparison between FSE-PROP-DWI versus SS-EP-DWI. Mann-Whitney U test was used for independent group comparison between PMAs versus WTs. Diagnostic performance was evaluated by receiver operating characteristics curve analysis. P < 0.05 was considered statistically significant. The Dice coefficient was statistically significantly higher on FSE-PROP-DWI than SS-EP-DWI for both tumors (P < 0.005). Mean ADC was statistically significantly higher in PMAs than WTs on both FSE-PROP-DWI and SS-EP-DWI (P < 0.005). FSE-PROP-DWI and SS-EP-DWI successfully distinguished PMAs from WTs with an AUC of 0.880 and 0.945, respectively (P < 0.05). Sensitivity, specificity, positive predictive value, negative predictive value and accuracy in diagnosing PMAs were 100%, 69.0%, 62.5%, 100% and 79.5% for FSE-PROP-DWI, and 100%, 82.8%, 75%, 100% and 88.6% for SS-EP-DWI, respectively. FSE-PROP-DWI is useful to distinguish parotid PMAs from WTs with less distortion of tumors but lower AUC than SS-EP-DWI.

Pleomorphic adenoma of buccal mucosa: a case report and review of the literature

BACKGROUND

Salivary gland neoplasms are rare, accounting for 3% to 5% of all head and neck tumors, and involvement of the minor salivary glands is uncommon. Pleomorphic adenoma (PA) is the most common benign neoplasm, which mainly affects the parotid gland. However, involvement of the cheek mucosa is very rare.

OBJECTIVE

This study reports a case of PA in the cheek mucosa. In addition, the etiopathogenesis, clinical and morphological features and differential diagnoses of PA are discussed, emphasizing the importance of knowledge about the characteristics of this tumor for a correct diagnosis.

CASE REPORT

A 50-year-old woman presented with a nodular lesion of endophytic growth in the left cheek mucosa. The lesion was small and well-delimited and had a normal mucosa color and intact surface. An excisional biopsy of the lesion was performed, and the diagnosis was PA.

CONCLUSION

Although the occurrence of PA in the minor salivary glands of the cheek mucosa is uncommon, the early establishment of a correct diagnosis and initiation of appropriate treatment are important because they permit effective management of the condition and improvement in the prognosis of patients.

Carcinoma ex pleomorphic adenoma: a case report and review of literature

Background

Carcinoma ex pleomorphic adenoma (CA-ex-PA) is extremely unusual in minor salivary glands of oral cavity. CAex-PA is a carcinomatous change as a primary or as a recurrence of pleomorphic adenoma.

Objective

Due to resemblance of clinical symptoms of Ca ex PA and benign pleomorphic adenoma, it is mandatory for surgeons to keep high degree of clinical alertness, considering the peculiarity of this tumor.

Case Report

54-year-old male presented with swelling on left side in the pre-auricular region from the middle of zygomatic arch to mastoid process and from tragus of the ear up to angle of mandible. Fine needle aspiration cytology revealed a mixture of benign and malignant components. Total left parotidectomy with left radical neck dissection followed by reconstruction with cervicodeltopectoral flap was performed. Combination of chemotherapy and radiotherapy were given to patient. Histologic examination and pre-operative fine needle aspiration cytology confirmed the diagnosis of Carcinoma ex pleomorphic adenoma (CA-ex-PA). Two-year follow-up of patient showed no recurrence of the lesion.

Conclusion

Due to the similarity in the clinical symptoms of CA-ex-PA and benign pleomorphic adenoma, it is vital that clinicians maintain a high degree of clinical vigilance, considering the oddity of this malignancy.

Metastasis of carcinoma ex pleomorphic adenoma to the brain without previous metastasis to the lungs or bones: a case report

Carcinoma ex pleomorphic adenoma is a rare type of cancer of the salivary gland that involves the malignant transformation of a primary or recurrent pleomorphic adenoma, which often metastasises to the lungs or bones, or both. To the best of our knowledge, however, nobody has reported a distant metastasis of this lesion to the brain without such previous metastasis. We report a case in a 64-year-old man.

Metastatic Pleomorphic Adenoma in the infratemporal fossa and neck following total parotidectomy after 30 years

Metastasising pleomorphic adenoma is rare and may occur years after surgical excision of a pleomorphic adenoma (PA). We present a 61-year-old woman with a right infratemporal PA with metastases to the cervical lymph nodes after 30 years following a total parotidectomy. She was treated successfully with a resection of the tumour with combined neck and mandibulotomy approach along with postoperative radiotherapy given subsequently.

Pleomorphic Adenoma of the Submandibular Gland: A Case Report

Salivary gland tumours are relatively rare and constitute about 3-4 % of head and neck tumours. Most of the tumours arise from parotid glands. Submandibular gland tumours are very rare. Pleomorphic adenoma of the submandibular gland is exceedingly rare tumour. Very few studies have been reported in the literature that is exclusively conducted on pleomorphic adenoma affecting submandibular gland. Patients usually present with a slow growing, painless and mobile mass without any other associated symptoms. Radiologic studies are usually unable to differentiate benign from malignant tumours in most cases. Recurrence is rare with complete en bloc excision of the tumour along with submandibular gland. Prognosis is excellent except for the rare cases of malignant transformation. This paper describes a case of pleomorphic adenoma affecting submandibular gland with brief review of current literature on submandibular gland tumours.

Primary Pleomorphic Lipoma of the Parotid Gland with Prominent Myxoid Change: Report of a Rare Case Mimicking Carcinoma Ex Pleomorphic Adenoma on Fine Needle Aspiration Cytology

We present a case of a primary 2.5 cm pleomorphic lipoma of the right parotid gland with prominent myxoid change which on FNA displayed features that mimicked a carcinoma or sarcoma ex pleomorphic adenoma. The patient was a 79 year old man with no oncological history or tumor elsewhere. On immunohistochemistry the neoplastic cells strongly expressed CD34. There was no expression of retinoblastoma protein, smooth muscle actin, S100-protein or cytokeratins (AE1/3 and CAM5.2). The Ki-67 proliferation index was low (< 2%). Fluorescence in situ hybridization was negative for MDM2 gene amplification.

Potential immmunohistochemical markers to characterize epithelial-mesenchymal transition in pleomorphic adenoma

BACKGOUND

The histogenesis process of pleomorphic adenoma (PA) of salivary gland continues to remain a controversial subject. In this neoplasm, transition occurs from an epithelial or myoepithelial cell to a stromal element and is called an epithelial-mesenchymal transition (EMT) resulting in heterogeneity. The present research was aimed to study the morphological characteristics of varied components and epithelial-mesenchymal transitions in PA using histopathological and immunohistochemical (IHC) analysis.

MATERIALS & METHODS

For this purpose 15 PAs cases were selected from the archives and from each case of PA and 5 cases of normal salivary gland, five additional sections were cut from each for immunohistochemical analysis using E- cadherin, vimentin and a-actin. The numbers of immunoreactive cells were semi- quantitatively measured and also determined the intensity of the immunostaining reaction.

RESULT

Immunohistochemically, as the cells transitioned from the lumial cells to descrete/detached cells of ductal structures, the percentage of positive cells tends to decrease for E- cadherin and increases for vimentin and actin. Additionally, neoplastic cells towards the periphery of ducal-cystic structures or completely detached cells in the stroma showed intense to moderate positivity for vimentin and alpha smooth muscle actin (a-SMA). Chondroid/ hyalinized or myxoid stroma showed variable staining with these markers.

CONCLUSION

Our study provides the evidence that epithelial-mesenchymal transition process represent the basic principle of the tisuse heterogeneity in pleomorphic adenomas.

[Pharyngeal space carcinoma ex pleomorphic adenoma：a case report]

Carcinoma ex pleomorphic adenoma is an epithelial malignant tumor of pleomorphic adenoma. This may be due to the accumulation of genetic instability caused by long-term pleomorphic adenomas. There are few reports of parapharyngeal space carcinoma ex pleomorphic adenoma in the literature study both at home and abroad. This article retrospectively summarized the clinical data of 1 case of pharyngeal space carcinoma ex pleomorphic adenoma and reviewed the literature. We strengthened the understanding of parapharyngeal space carcinoma ex pleomorphic adenoma, improve the accuracy of diagnosis and reduce misdiagnosis and mistreatment.

[Retrospective analysis of 896 cases of parotid gland tumor]

PURPOSE

To review the clinical data of patients undergoing operation, in order to summarize the incidence, proportion, clinical examination and diagnostic methods of parotid tumors.

METHODS

Eight hundred and ninty-six cases of parotid gland tumors were collected from 2008 January to 2015 July from department of oral and maxillofacial surgery in Shengjing Hospital of China Medical University. A retrospective study of the clinical data was carried out, including age, gender, tumor location, diagnostic methods and pathological results.

RESULTS

In 896 patients with parotid gland tumor, 432 were male, 464 were female, the ratio was 1:1.07; 431 cases were on the left side, 454 cases were on the right side, 11 cases were bilateral; The proportion of parotid tumor was higher in patients aged 31 to 70 years old. 786 cases were benign, 110 cases were malignant, the ratio of benign to malignant was 7.15:1. Pleomorphic adenoma, Warthin tumor and basal cell adenoma were the most common types of benign tumors, while mucoepidermoid carcinoma, acinic cell carcinoma and adenoid cystic carcinoma accounted for the most of malignant tumors.

CONCLUSIONS

The pathological types of parotid gland tumor are complicated. Clinical examination and imaging features are helpful to diagnosis. The accuracy is high in diagnosis of parotid gland tumor by frozen section, which is useful to assist making treatment plan.

Immunohistochemical Staining of Histological Fragments Derived from Salivary Gland Tumour Fine-Needle Biopsy Aspirates

OBJECTIVES

The aim of this study was to describe a method for analysing histological fragments derived from fine- needle aspirate biopsy (FNAB) of salivary gland tumours (SGTs), and to evaluate the use of immunohistochemistry (IHC) on them.

STUDY DESIGN

We reviewed all 509 FNAB pathology reports taken from SGTs at Helsinki University Hospital, Finland, between 1999 and 2009. In 51% of the cases (n = 209) "histo-fragments" had been obtained and 31 had been further analysed by IHC. Of these, 25 (81%) were available for review. We evaluated the benefit of IHC by relating its added value to the preoperative cytological diagnosis and its accuracy compared with the postoperative histological diagnosis.

RESULTS

Most of the samples analysed by IHC were assigned a malignant diagnosis, with 12 different types of malignancy represented. IHC was advantageous in 76% of the cases. In the 108 studies using IHC in this series, antibodies to 36 different antigens were used.

CONCLUSION

Analysis of histo-fragments in FNABs using IHC can be valuable in specific differential diagnostics and raises diagnostic accuracy in SGTs.

A diagnostic challenge

A 74 year-old woman presented with a 9 month history of a slowly enlarging exophytic lesion over her left nasal alar. Examination revealed a firm, cystic mass fixed to underlying skin. It was pedunculated with occasional superficial telangiectasia and a violaceous hue. A differential diagnosis of dermoid or sebaceous cyst, dermatofibroma, and neurofibroma was considered. Histopathological examination confirmed the rare diagnosis of chondroid syringoma (CS), which has a reported incidence of 0.01- 0.098% of excised skin tumors. It is unusual for CS to present in an elderly woman, as these benign primary skin tumors normally present in adult males. Dermoscopy does not reveal any specific features and the diagnosis is difficult to make based on clinical examination alone.

[Diagnosis and treatment of the tumors of the parotid region in Pediatrics: cohort]

INTRODUCTION

Parotid tumors are rare in children and usually have multiple differential diagnoses that require different diagnostic and treatment methods.

MATERIAL AND METHODS

Retrospective cohort study of all consecutive pediatric patients with parotid tumors that were treated in Pediatric Surgery Service of Hospital Italiano de Buenos Aires.

RESULTS

Twenty-two patients with parotid tumors were included and 72% (n=16) were female patients. The median age was 10 years (range: prenatal to 19 years). Imaging studies: ultrasound, CT and MRI. Diagnostic methods: needle or open biopsy (14), biopsy of lymph nodes (3), imaging (4), blood test (1). Treatment: surgical resection (12), medical treatment (7), sclerotherapy (2). Diverse histological diagnosis were obtained: pleomorphic adenoma (4), infantile hemangioma (4), PNET (2), low flow vascular malformation (2), Castleman's disease (1), schwannoma (1), neuroblastoma (1), alveolar rhabdomyosarcoma (1), mucoepidermoid carcinoma (1) RICH (Rapidly Involuting Congenital Hemangioma) (1), granulomatous disease (1), reactive adenitis (1), parotid cyst (1), ALL (Acute Lymphoblastic Leukemia) (1). Follow-up (42,5 months): 18 patients are free of disease, 3 are currently under medical treatment and 1 died.

CONCLUSIONS

Our series shows the diversity that parotid tumor can present in pediatric population and is consistent with the literature there the incidence of benign lesions are predominant. However, it is difficult to predict risk of malignancy. An exhaustive diagnosis is important, using complementary methods and biopsy whenever that is necessary.

Pedunculated carcinoma ex pleomorphic adenoma of the nasal cavity: A unique case report

BACKGROUND

A carcinoma ex pleomorphic adenoma (CXPA) is an epithelial malignancy arising in or from a benign pleomorphic salivary adenoma. The parotid gland is the most common location of CXPAs. Minor salivary gland CXPAs of the nasal cavity are exceedingly rare, with only 6 documented in the literature.

METHODS AND RESULT

We present a 7th case: an unusual pedunculated intranasal CXPA, which had a favorable outcome after a wide endoscopic excision and the longest follow-up period reported to date. The clinical features, immunohistochemical characteristics, treatment choices, and disease outcomes of the intranasal CXPAs reported in previous studies are also reviewed.

CONCLUSION

This case demonstrates the importance of considering the possibility of CXPA in the differential diagnosis of minor salivary gland malignancies in the nasal cavity.

Chondroid syringomas: an immunohistopatological analysis

BACKGROUND

Chondroid syringoma is a rare benign skin adnexal tumor composed of both epithelial and mesenchymal components, and is known as a cutaneous mixed tumor. Its clinical diagnosis is generally incorrect, and an exact diagnosis can only be made with histopathological investigations. The aim of this study was to determine the clinicopathological findings of the cases diagnosed with chondroid syringoma.

METHODS

In this study, over the period from January 2008 to March 2014, a total of 2661 excised skin lesions were evaluated for the clinicopathological findings, and fifteen cases were diagnosed with chondroid syringoma. Various parameters such as gender, mean age, tumor localization and immunohistochemical markers (pan-cytokeratin, vimentin, S-100 protein, CEA-(M) and p53 were examined.

RESULTS

Of the15 cases diagnosed with chondroid syringoma, 10 (67%) were male and 5 (33%) were female. The mean age of the patients was 46 (range 11-80 years). The chondroid syringomas were positive for pan-cytokeratin (87%), vimentin (100%), S-100 protein (100%), CEA-M (53%) and p53 (80%).

CONCLUSIONS

Chondroid syringomas should be included in the differential diagnosis of a slowly growing, nodular mass in the dermis. Definitive diagnosis of the tumor is made by histopathological examination. Difficult cases may benefit from immunohistochemical examination.

PLAG1: An Immunohistochemical Marker with Limited Utility in Separating Pleomorphic Adenoma from Other Basaloid Salivary Gland Tumors

OBJECTIVE

Fine-needle aspiration (FNA) diagnosis of salivary gland neoplasms is often challenging. Differentiating between pleomorphic adenomas (PA) and other basaloid neoplasms, especially basal cell adenoma (BCA) and adenoid cystic carcinoma (AdCC), can be difficult in cellular aspirates. PLAG1 (PA gene 1) is a proto-oncogene, which is frequently rearranged in PAs, leading to the aberrant expression of its protein. PLAG1 IHC expression has been reported to be positive in most PAs. The aim of this study was to evaluate the sensitivity and specificity of PLAG1 to differentiate PA from other basaloid neoplasms.

STUDY DESIGN

Immunohistochemical evaluation of PLAG1 was performed on 125 cases (52 FNAs and 73 surgical excisions). Nuclear staining of tumor cells was scored by the intensity and percentage of positive tumor cells. A combined score of >5 was defined as positive.

RESULTS AND CONCLUSION

The sensitivity (55%) and specificity (75%) of PLAG1 in diagnosing PA in FNAs is relatively modest thus limiting its diagnostic utility. BCAs and AdCCs showed PLAG1 false positivity, in surgical excision specimens and less so in FNAs. This may be due to limited sampling or tumor heterogeneity. Hence, PLAG1 is a modest marker for PAs in FNAs.

Biomarker Analysis in Carcinoma ex Pleomorphic Adenoma at an Early Phase of Carcinomatous Transformation

Diagnostic criteria for intracapsular carcinoma ex pleomorphic adenoma (CXPA) are subjective and vary among authors. Biomarker analysis, which could provide more objective evaluation of these tumors, has rarely been studied in intracapsular CXPA. Immunohistochemical evaluation of c-erbB-2, p53 protein, bcl-2, and Ki-67 was performed in 8 cases of CXPA at an early phase of malignant transformation (4 intracapsular and 4 minimally invasive) and in 17 pleomorphic adenomas (PA). In all cases of CXPA, p53 and Ki-67 were demonstrated predominantly in luminal cells of benign and malignant areas, significantly more in the latter. Few benign myoepithelial cells were p53 positive. c-erbB-2 reactivity was strongly associated with atypical luminal cells. Bcl-2 expression was weak and focal in malignant areas from 2 cases. In conclusion, both p53 and c-erbB-2 proteins appear to be involved at an early stage of malignization of PA. In PA with atypical cells, evaluation of the expression of these 2 markers provides more objective criteria for the diagnosis of intracapsular CXPA.

PLAG1 expression is maintained in recurrent pleomorphic adenoma

The proto-oncogene (pleomorphic adenoma gene 1 (PLAG1)) is immunohistochemically overexpressed in pleomorphic adenoma (PA). Its expression in recurrent pleomorphic adenoma (RPA), however, has not been investigated. Since complex mechanisms are involved in tumor recurrence, the aim of this study was to investigate whether PLAG1 overexpression occurs in RPA. We studied PLAG1 protein expression in 40 PAs and 36 RPAs by immunohistochemistry. Cases with immunopositive cells were classified into two categories, between 10 and 50 % and >50 %. In both groups, PLAG1 expression was observed in both epithelial and myoepithelial cells. Of PAs, 37 cases (93 %) were positive, while this was the case in 34 RPA cases (94 %). Our findings suggest that in addition to morphological similarity, PA and RPA express PLAG1, which might play a role in tumor recurrence. Furthermore, as for PA, expression of PLAG1 can be considered a valuable diagnostic marker for RPA.