Myoepithelioma: definitions and diagnostic criteria

Unveiling rarity: Myoepithelioma in the minor salivary gland of buccal mucosa - A case report

INTRODUCTION

Tumours of salivary glands are rare and have various histo-pathological subtypes. Myoepitheliomas were first classified by Sheldon et al. and the criterion to classify or diagnose it was first defined by Barnes et al. and Sciubba and Brannon. Myoepithelioma accounts for less than 1 % of all salivary gland tumours, 40 % of these tumours occur in the parotid gland while 21 % occur in the minor salivary glands. A case of myoepithelioma of a minor salivary gland of the cheek is described, emphasizing the problems of the differential diagnosis.

PRESENTATION OF THE CASE

A 40-year-old female reported to the department with a complaint of a cheek bite on her right side for a few months. The physical examination showed a presence of lobulated whitish mucosa on the right buccal mucosa at the level of the occlusal plane, on palpation it revealed a non-painful mass approximately 1.5 cm in radius, mobile to bimanual palpation. An excisional biopsy was performed under local anaesthesia. Microscopic and immunohistochemistry confirmed the tumour to be a myoepithelioma of a minor salivary gland with the absence of definitive features of malignancy.

DISCUSSION

Due to their infrequency and multiplicity of histopathology, myoepitheliomas present difficulties in diagnosis. Cellular varieties can be misdiagnosed as malignancies. A key to determining diagnostic criteria for myoepitheliomas is to study cellular morphology, cytoplasmic filament expression, and ultrastructural features of the tumour and apply this information to defining myoepitheliomas.

CONCLUSION

Myoepitheliomas are rare tumours, utilization of immunohistochemical staining and electron microscopy are useful tools for the diagnosis of myoepitheliomas to ensure proper treatment and follow-up.

Clinicopathological features and prognostic factors of salivary gland myoepithelial carcinoma: institutional experience of 42 cases

Myoepithelial carcinoma (MECA) is a rare type of carcinoma for which the clinicopathological features and prognostic factors have not yet been fully clarified. A retrospective study of 42 patients diagnosed with salivary gland MECA was performed, focusing on the clinicopathological features and prognostic factors. Of the 42 patients, 20 died of cancer, 20 lived without tumour, one lived with distant metastasis, and one was lost to follow-up. Overall, 69.0% had tumour recurrence, 16.7% had cervical nodal metastasis, and 21.4% had distant metastasis. The 5-year overall survival rate was 70.2%. Kaplan-Meier analysis revealed that patients with pathological positive lymph nodes (pN+), multiple recurrences of tumour, and higher histological grade had worse overall survival. Multivariate Cox analysis indicated pN+ and higher histological grade to be independent predictors of decreased survival. The 5-year overall survival rate in the pN0 group was 87.5%, while that in the pN+ group was 28.6%. In conclusion, myoepithelial carcinoma can be defined as a tumour with a high incidence of recurrence and poor prognosis, especially in pN+ patients. Pathological positive lymph nodes and histological grade may serve as predictors of survival.

Top Ten Differentials to Mull Over for Head and Neck Myoepithelial Neoplasms

BACKGROUND

Myoepithelial neoplasms of the salivary gland are benign or malignant neoplasms composed exclusively of neoplastic myoepithelial cells. These tumors, including the benign myoepithelioma and the malignant counterpart myoepithelial carcinoma, exhibit a wide range of cytomorphologic features and architectural patterns.

METHODS

Review.

RESULTS

Myoepithelial cells can be epithelial, plasmacytoid, clear cell, spindle cell, and/or oncocytic cell, arranging as trabeculae, solid sheets, nests, cords, and/or single cells. A stromal component is commonly but not universally present, Therefore, their differential diagnoses are quite broad, including salivary gland neoplasms especially those with a myoepithelial component, plasmacytoma, melanoma, and various mesenchymal tumors.

CONCLUSION

In this review, we summarize the characteristic histologic features, useful immunohistochemical panel, and common molecular alterations of myoepithelial tumors and their top differential diagnoses. A logical stepwise algorithmic approach and an immunohistochemical panel to include multiple myoepithelial markers are essential to establish the correct diagnosis.

Myoepithelial carcinoma of major salivary glands: Analysis of population-based clinicopathologic and prognostic features

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The demographic features of major salivary glands myoepithelial carcinoma has been analyzed using propensity score-matching.

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The correlation between tumor stage and prognostic for patients with myoepithelial carcinoma is conformed.

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The radiotherapy is a favorable factor for overall survival in patients with myoepithelial carcinoma.

Background

This study aimed to investigate the effect of demographic characteristics and disease stage on the survival outcomes of patients with myoepithelial carcinoma (MECA) of the salivary glands, and to assess the role of radiotherapy in these patients.

Methods

The Epidemiology, Surveillance and End Results database was queried from 2000 to 2018 to identify patients with MECA. Data pertaining to the tumor stage, size, histological grade, and demographic characteristics were analyzed. The relationship between clinicopathological features and overall survival (OS) was assessed using statistical analyses.

Results

In total, 290 patients (137 men and 153 women) were identified. The parotid gland was the most common tumor location (76.6% patients). Approximately half of the patients had locally advanced tumors, and 14.5 and 6.6% had lymph node and distant organ involvement, respectively. The median OS was 142 months, while the survival rates at 120 months and 180 months were 53% and 39%, respectively. In the cohort, 160 patients (55.2%) underwent surgery alone, while 130 patients (44.8%) underwent surgery combined with radiotherapy. Multivariate Cox analysis revealed that histopathological grade, stage, T3 stage (hazard ratio [HR]: 2.47, P = 0.039), T4 stage (HR: 3.33, P = 0.011), N2 stage (HR: 6.59, P = 0.002), and M1 stage (HR: 2.72, 95%confidence interval [CI]: 1.03–7.19; P = 0.044) were associated with poor prognosis. Radiotherapy (HR: 0.58, P = 0.042) was a favorable factor for OS, and it reduced the mortality risk by 42%.

Conclusions

Histological grade, stage, and radiotherapy are independent risk factors for OS. The decision to administer chemotherapy for MECA should be made with caution. Adjuvant radiotherapy is recommended in high-risk patients.

What is hiding behind S100 protein and SOX10 positive oncocytomas? Oncocytic pleomorphic adenoma and myoepithelioma with novel gene fusions in a subset of cases

Oncocytomas (OCs) in salivary glands are rare benign tumors composed of mitochondria-rich epithelial cells (oncocytes), mostly localized in the parotid gland. The treatment of choice is simple excision. Extensive oncocytic metaplasia of pleomorphic adenoma (PA) and myoepithelioma (ME) can be diagnostically challenging and may camouflage the correct diagnosis. These tumors should be treated more carefully compared with OC, given the risk of frequent recurrences and the possibility of malignant transformation. We have investigated 89 oncocytic lesions from our files, including OC (n = 74) and metaplastic oncocytic variant of PA/ME (n = 15). All OCs were stained for S100 protein and SOX10. The tumors with immunohistochemical expression of one or both markers were tested by next-generation sequencing (NGS). The NGS results were confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and/or fluorescence in situ hybridization (FISH). Ten cases originally diagnosed as OC, and 1 low-grade uncertain oncocytic tumor (11/74) revealed nuclear-cytoplasmic and/or nuclear positivity for S100 protein and/or SOX10, respectively. Fusion transcripts CHCHD7-PLAG1 and GEM-PLAG1 were found in 2 cases (1 fusion in each), and these were confirmed by RT-PCR and PLAG1 break-apart FISH probe, respectively. Another 5 cases were positive for PLAG1 rearrangement by FISH. In the control group of 15 oncocytic PA/ME, 4/15 tested tumors harbored gene fusions including NFT3-PLAG1, CHCHD7-PLAG1, FBXO32-PLAG1, and C1orf116-PLAG1 (1 fusion in each case) as detected by NGS. Two fusions were confirmed by RT-PCR, 1 case by FISH, and 1 case was not analyzable by FISH. We additionally tested 24 OCs negative for S100 protein and SOX10 by immunohistochemistry (IHC) and by FISH for rearrangement of PLAG1 gene, but none of them were positive. SOX10 and/or S100 protein immunopositivity in conjunction with rearrangement of the PLAG1 gene assisted in reclassification of a subset of oncocytomas as oncocytic variants of PA and ME. Therefore, we recommend to include S100 protein and SOX10 IHC when diagnosing tumors with predominantly oncocytoma-like differentiation. In addition, by NGS, 3 new gene fusions were detected in oncocytic ME, including NTF3-PLAG1, FBXO32-PLAG1, and GEM-PLAG1, and a new fusion C1orf116-PLAG1 was detected in oncocytic PA.

A first case report of clinical response to targeted therapy in a patient with primary myoepithelial carcinoma of the lung harboring EGFR exon 19 deletion

BACKGROUND

Primary myoepithelial carcinoma of the lung is a rare subtype in lung cancer. Comprehensive molecular profiling of myoepithelial carcinoma of the lung is absent, neither was clinical evidence of targeted therapy available for this disease. Therefore, the optimal treatment regimen of this tumor needs to be established.

CASE PRESENTATION

Here we present a case of a 68-year-old patient with stage IVB primary myoepithelial carcinoma of the lung who harbored EGFR exon 19 deletion and KRAS mutation and underwent icotinib targeted therapy, achieving partial response (PR) with progression free survival (PFS) of 3 months.

CONCLUSION

To our knowledge, this study describes the first documented case of primary myoepithelial carcinoma lung cancer patient harboring EGFR exon 19 deletion and KRAS mutation, and showed clinical efficacy of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI) treatment in this patient.

Myoepithelioma of bone: ultrastructural, immunohistochemical and molecular study of three cases

Primary intraosseous myoepithelial tumors are rare neoplasms with only a handful of cases described in the medical literature. To date, intraosseous variant of benign myoepithelioma, due to its rarity, has not been studied ultrastructurally, and only one case of a malignant intraosseous myoepithelioma has been described. Three cases were retrieved from the files at the Massachusetts General Hospital (MGH). A diagnosis of benign myoepithelioma was made in case 1 and malignant epithelioma in cases 2 and 3. Ultrastructurally, intermediate filaments (without dense bodies) were found in each case with an abundance in case 1 and lesser amounts in cases 2 and 3. Surprisingly, cell junctions were not identified in case 1. However, they were found occasionally as intermediate junctions in case 2 and were easily identified as desmosome like junctions in case 3. The nucleus was irregular in the neoplastic cells of benign myoepithelioma which contrasted with cases 2 and 3 where the nuclei were oval yet had visible nucleoli. Herein, we add three new cases, including two new cases of malignant myoepithelioma. We also provide the first ultrastructural description of benign myoepithelioma of bone.

Spindle cell myoepithelioma of the parotid gland

Myoepithelioma was recognized as a histological distinct entity by the World Health Organization (WHO) in 1991. Myoepithelial cells are believed to be of ectodermal origin. In salivary glands, the myoepithelial cells that surround the intercalated ducts are spindled, which is in contrast to the large stellate ones that envelop the acini. Myoepithelioma is a benign salivary gland tumor that consists entirely of myoepithelial cells. A 53-year-old man presented with a 1-year history of a painless mass originating from the right parotid gland. The mass grew rapidly reaching a size of approximately 6 cm. The patient had no facial paralysis. The authors performed right parotidectomy. Immunohistochemistry study of this tumor showed that it was positive for vimentin, positive for S-100, focally positive for pancytokeratin, and focally positive for p63 and that it had a Ki-67 labeling index (below 10%). Additionally, the tumor was negative for epithelial membrane antigen, negative for actin, negative for desmin, negative for CD34 and negative for anaplastic lymphoma kinase. The authors present a case of benign spindle cell myoepithelioma of the parotid gland in a 53-year-old man diagnosed after immunohistochemistry study, describing its importance, along with a brief review of the literature.

Plasmacytoid cells in salivary pleomorphic adenoma: an alternative interpretation of their immunohistochemical characteristics highlights function and capability for epithelial-mesenchymal transition

OBJECTIVES

Plasmacytoid cells (PLCs) in salivary pleomorphic adenoma (SPA) are regarded as modified neoplastic myoepithelia and define plasmacytoid myoepithelioma (pMYO). However, histochemically, immunohistochemically and ultrastructurally, PLCs fail to demonstrate frank myogenous properties. Epithelial-mesenchymal transition (EMT) may explain the phenotypes in SPA. Our aim was to evaluate (1) PLCs with accepted or purported myoepithelial and EMT-related markers; and (2) pMYOs for PLAG1 aberrations by using fluorescence in situ hybridization.

STUDY DESIGN

Eight SPAs with or without PLC-predominance and 3 pMYOs were immunohistochemically studied.

RESULTS

PLCs in SPA and pMYO exhibited strong, scattered to diffuse positivity for K7, rare K14 positivity and were mostly negative for α-smooth muscle actin, h-caldesmon, and p63/p40. S100 staining was strong and diffuse, whereas calponin was variable. DOG1 was negative. PLCs in pMYO and PLC-rich SPA exhibited selective or diffuse WT1 and D2-40 immunoreactivity. EMT markers SNAIL/SLUG exhibited strong and variable immunoreactivity in PLCs in contrast to weak or absent E-cadherin expression. SOX10 was diffusely and strongly positive. PLAG1 rearrangement was present in 1 pMYO.

CONCLUSIONS

PLCs mostly fail to express myoepithelial markers; PLCs are neoplastic cells adapting to microenvironmental changes and capable of EMT; and tumors composed solely of PLCs are apparently SPAs depleted of a ductal component.

Neoadjuvant radiation therapy for the management of myoepithelial carcinoma of the upper extremity

Myoepithelial tumors of the soft tissue are a rare tumor displaying myoepithelial elements and lacking obvious ductal differentiation. The rarity of these precludes any evidence-based consensus regarding optimal management. Nevertheless, the current approach to these lesions begins with amputation or complete excision. The efficacy of neoadjuvant or adjuvant radiation therapy or chemotherapy has not been established. Here, we present the first report to the authors' knowledge of neoadjuvant radiation therapy for the treatment of this rare soft tissue neoplasm and review the management and outcomes of published cases of myoepithelial carcinoma. A patient with a soft tissue myoepithelial carcinoma that declined both amputation and chemotherapy was treated with neoadjuvant radiation therapy and wide surgical excision followed by a brachytherapy boost to the resected tumor bed. Neoadjuvant radiation therapy resulted in an excellent response with extensive treatment-related changes consisting predominantly of fibrosis, hyalinization and hemorrhage and only 10% residual viable myoepithelial carcinoma present in the surgical specimen.

Thoracic Myoepithelial Tumors: A Pathologic and Molecular Study of 8 Cases With Review of the Literature

Thoracic myoepithelial tumors (MTs) are a rare group of tumors showing predominant or exclusive myoepithelial differentiation. They are poorly characterized from both a morphologic and genetic standpoint, in particular features that separate benign from malignant behavior. We examined the histologic and immunohistochemical features of 8 primary thoracic MTs and performed fluorescence in situ hybridization for EWSR1, FUS, PLAG1, and HMGA2, as well as several partner genes. Half (4/8) of the MTs occurred in large airways, and 3 had infiltrative borders. All cases showed immunoreactivity for epithelial markers, in conjunction with S100 protein or myogenic markers. MTs showed morphologic characteristics analogous to MTs at other sites, with no tumors having ductal differentiation. Necrosis and/or lymphovascular invasion was present in 5 cases, with mitotic activity ranging from 0 to 6 mitoses/2 mm² (mean 1). Metastases occurred in 2 cases, and no patients died of disease. Gene rearrangements were identified in half of the cases, with EWSR1-PBX1, EWSR1-ZNF444, and FUS-KLF17 fusions identified in 1 case each and 1 case having EWSR1 rearrangement with no partner identified. No cases were found to have HMGA2 or PLAG1 abnormalities. Compared with fusion-negative tumors, fusion-positive tumors tended to occur in patients who were younger (50 vs. 58 y), female (1:3 vs. 3:1 male:female ratio), and demonstrated predominantly spindle and clear cell morphology. Using a combined data set of our case series with 16 cases from the literature, poor prognosis was significantly correlated with metastases (P=0.003), necrosis (P=0.027), and ≥5 mitoses/2 mm²/10 high-power field (P=0.005). In summary, we identify a subset of thoracic MTs harboring rearrangements in EWSR1 or FUS, and our data suggest that necrosis and increased mitotic activity correlate with aggressive clinical behavior.

Myoepithelial Carcinoma: The Role of Radiation Therapy. A Case Report and Analysis of Data From the Surveillance, Epidemiology, and End Results (SEER) Registry

PURPOSE/OBJECTIVE

The role of radiation therapy in the treatment of myoepithelial carcinoma (MC) is unknown. We present a case of a high-grade soft-tissue MC in a pediatric patient and retrospectively examine the effect of postoperative radiation on survival in patients with MC.

MATERIALS AND METHODS

Our patient was treated with 4 cycles of ifosfamide, cisplatin, and etoposide followed by 3 cycles of ifosfamide vincristine and etoposide. Radiation was delivered to a total dose of 5580 cGy in 180 cGy/fraction to the surgical bed with a 2 cm margin starting after the third cycle of chemotherapy. The Surveillance, Epidemiology, and End Results (SEER) registry database was queried for cases of surgically resected MC. Retrospective analysis was performed with the endpoint of overall survival (OS).

RESULTS

Two hundred thirty-four cases of MC were identified; for 62 of these cases, the grade of the tumor wasidentified. Of these 62 patients, 27 received postoperative radiation. OS was improved with adjuvant radiation therapy in patients with grade III or IV MC (P<0.01) as determined by the log-rank test.

CONCLUSIONS

This analysis of SEER data showed an OS benefit with adjuvant radiation therapy in the treatment of high-grade MC. Physicians should report all cases of MC to improve clinical decision making in the treatment of this rare disease.

Prognostic Factors in Myoepithelial Carcinoma of the Major Salivary Glands

OBJECTIVES

(1) Identify all cases of myoepithelial carcinoma of the major salivary glands from the National Cancer Data Base (NCDB). (2) Analyze the effect of grade, stage, and regional nodal metastasis on survival in myoepithelial carcinoma of the major salivary glands.

STUDY DESIGN

Retrospective review of NCDB.

SETTING

Multicenter data pooled from 1998 to 2012 in the NCDB.

METHODS

We identified all reported cases of myoepithelial carcinomas of the major salivary glands from the United States from 1998 to 2012 in the NCDB. Clinical parameters were then examined and analyzed for predictors of survival.

RESULTS

A total of 473 cases of myoepithelial carcinoma were identified. Of the reported cases, 38.1% were low grade; 26.7%, intermediate grade; and 35.2%, high grade. When presenting stage was examined, 24.4% were stage I; 30.6%, stage II; 22.5%, stage III; 12.2%, stage IVa; 3.0%, stage IVb; and 4.1%, stage IVc. At presentation, 18.7% of patients had regional nodal disease, and 4.5% had distant metastases. The 3- and 5-year survival rates were 73% and 64%, respectively. The presence of nodal disease significantly reduced mean survival time versus those without (64 vs 108 months, P < .001), as did high-grade disease compared with low grade (67 vs 114 months, P < .001) and stage III/IV compared with stage I/II disease (61 vs 118 months, P < .001).

CONCLUSIONS

The presence of regional nodal disease, high-grade disease, and advanced stage are predictors of lower survival in myoepithelial carcinoma. Further studies based on types of treatment are warranted.

Pleomorphic Adenoma of the Parotid Gland: Report of a Case With Review of Literature

Background

Pleomorphic adenomas are benign salivary gland tumors, which predominantly affect the superficial lobe of the parotid gland. The “pleomorphic” nature of the tumor can be explained on the basis of its epithelial and connective tissue origin. The tumor has a female predilection between 30–50 years of age. Slowly progressing asymptomatic swelling is the usual presentation of the tumor. Surgical excision of the tumor mass forms the mainstay of treatment, with utmost care taken to preserve the facial nerve.

Case Details

This case report aims to throw light on an interesting case of pleomorphic adenoma of the parotid gland in a 50 years old female patient. The patient presented with a slowly progressing asymptomatic swelling on the left side of the face. There is also a special emphasis to a detailed review of literature.

Conclusion

Salivary gland neoplasms can occur at any site where salivary tissue is present. Pleomorphic adenoma is the commonest salivary gland tumor characterized by diverse histomorphological features. Early diagnosis and treatment plan entails thorough history taking, clinical examination, coupled with radiographic and histopathological findings.

Benign neck masses showing restricted diffusion: Is there a histological basis for discordant behavior?

Diffusion weighted imaging (DWI) evolved as a complementary tool to morphologic imaging by offering additional functional information about lesions. Although the technique utilizes movement of water molecules to characterize biological tissues in terms of their cellularity, there are other factors related to the histological constitution of lesions which can have a significant bearing on DWI. Benign lesions with atypical histology including presence of lymphoid stroma, inherently increased cellularity or abundant extracellular collagen can impede movement of water molecules similar to malignant tissues and thereby, show restricted diffusion. Knowledge of these atypical entities while interpreting DWI in clinical practice can avoid potential misdiagnosis. This review aims to present an imaging spectrum of such benign neck masses which, owing to their distinct histology, can show discordant behavior on DWI.

Pathophysiology of myoepithelial cells in salivary glands

Myoepithelial cells (MECs) are considered to be a key participant in most salivary gland diseases, particularly tumors. MECs structurally resemble both epithelial cells and smooth muscles. Diagnostic dilemmas caused are due to inadequacy of characterizing the wide spectrum of morphologic and immunologic features which are different for both normal and neoplastic MECs. This article discusses the development, functions and structure of both normal and neoplastic MECs, their staining properties and differences in the morphologic and immunophenotypic properties of the MEC in detail. It also describes the role of MEC in pathogenesis and morphogenesis of various nonneoplastic and neoplastic salivary gland lesions and thereby are responsible for the myriad histopathology of salivary gland tumors.

Salivary gland myoepithelial carcinoma

Salivary gland myoepithelial carcinoma (MC) or malignant myoepithelioma is a rare entity. MC usually presents as a slow-growing painless mass arising in the parotid gland, but may involve other salivary glands. This tumour may be particularly locally aggressive, but its clinical and biological features are not yet fully understood. MC may arise from pre-existing benign lesions, such as pleomorphic adenomas or benign myoepitheliomas, or may arise de novo. It usually affects patients over 50 years old, with no gender preference. Because it is often asymptomatic, the presentation and diagnosis can be delayed by months, even years. The current WHO classification considers MC to be an intermediate- to high-grade malignancy. Other published data suggest it is likely to be a high-grade neoplasm, consistent with its aggressive behaviour. Its epidemiology, histopathological features, immunohistochemical profile, clinical behaviour and optimal management are not well understood. Following review of the current literature we aim to address these.

Prognostic factors in myoepithelial carcinoma of salivary glands: a clinicopathologic study of 48 cases

Myoepithelial carcinoma (MECA) is an underrecognized rare tumor with a diverse clinical behavior. The histologic features of this tumor are not well characterized, much less its grading, which is controversial. The objective of this study is to provide a better characterization of MECA and its prognostic factors. A total of 48 cases were retrieved from the pathology files. The cases were subjected to a detailed histopathologic, immunohistochemical, statistical, and clinical analysis. Tumors were classified as de novo MECA in 22 cases (46%) and carcinoma ex-pleomorphic adenoma (CA ex-PA) in 26 cases (54%). Tumor necrosis, high mitotic count (≥6/10 high-power fields), and severe pleomorphism were identified in 38%, 33%, and 21%, respectively. Perineural invasion, vascular invasion, and positive margins were noted in 10%, 12%, and 47%, respectively. Median follow-up was 38 months. Four patients had lymph node metastasis at presentation, 9 developed local recurrences, and 12 had distant metastases with the lung being the most common site (83%). The presence of CA ex-PA, necrosis, and vascular invasion correlated significantly with disease-free survival (P=0.02, 0.01, 0.03, respectively). No distant recurrence was noted in all 23 patients lacking necrosis in their neoplasms (median follow-up: 44 mo). MECA is a relatively aggressive tumor that is associated with a high rate of distant metastasis (27%). Compared with de novo MECA, CA ex-PA correlates with worse clinical outcome. A grading system based on the presence of tumor necrosis should be used to identify high-grade MECA and predict its clinical behavior.

Small cell carcinoma of the lung in a treated case of Myoepithelial carcinoma of the tongue--report of a rare case with illustrated review of the literature

Myoepithelial carcinoma has rarely been reported in the oral cavity and oropharynx. We found only 6 cases of myoepithelioma of the tongue reported till date. Two cases had a benign myoepithelioma; four had epithelial-Myoepithelial carcinoma. The present case had malignant myoepithelioma, a distinct entity from other histologies.

Myoepithelial Carcinoma of the Nasopharynx: Report of a Rare Case and a Review of the Literature

Salivary gland carcinomas are very rare in the nasopharynx, with the most frequent histologic types being adenoid cystic carcinoma, mucoepidermoid carcinoma and adenocarcinoma, not otherwise specified. Myoepithelial carcinoma (MECA) is a rare tumor of the salivary glands, and there are only three previously reported cases of nasopharyngeal MECA. The case presented is the fourth reported case of MECA in the nasopharynx. Due to the morphologic heterogeneity of MECA, immunohistochemistry is indispensable in ascertaining the diagnosis. MECA is a locally aggressive tumor, but the long-term prognosis of this tumor in the nasopharynx remains uncertain. In our case the tumor was unresectable and the patient was given chemo-radiotherapy. Despite this, residual tumor was seen on nasoscopy 5 months after initial diagnosis and was documented on a re-biopsy which displayed the same histomorphologic features as the original tumor.

Myoepithelial Carcinoma of the Salivary Glands: A Clinicopathologic Study of 29 Patients

PURPOSE

Myoepithelial carcinomas (MECs) of the salivary glands are relatively rare. The clinicopathologic features, immunohistochemical profile, and biologic behavior have not been well-defined.

MATERIALS AND METHODS

A total of 29 patients with MEC diagnosed during a 10-year period were included in the present study focusing on the biologic behavior, and the pathologic samples of 28 patients were collected for additional investigation of the histologic characteristics. Thirteen samples with detailed immunohistochemical results were included for illustrating immunohistochemical profiles.

RESULTS

The parotid gland (n = 7) was the most common site involved, followed by the palate (n = 6) and the submandibular gland (n = 6). A multinodular growth pattern (n = 14) and sheet-like arrangement of tumor cells (n = 14) were observed. Of the 28 MEC samples, 14 (50%) were epithelioid, 5 (18%) were clear cell, 5 (18%) were plasmacytoid, 3 (11%) were mixed cell type, and 1 (3%) was spindle. The tumor-associated matrix was more prevalently hyalinized than myxoid. Of the 28 cases, 12 (43%) were classified as high grade and 16 (57%) as low grade. Immunohistochemical analysis revealed pan-cytokeratin (92.3%), smooth muscle actin (36%), S-100 protein (54.5%), and p63 (91.7%) positivity and carcinoembryonic antigen (100%) negativity. Ki-67 was immunoreactive in 62% of the MECs, with the Ki-67 labeling index ranging from less than 5 to 20%. Eleven patients developed recurrence (median disease-free survival 43 months) and 11 (44%) developed metastases. Two patients (8%) died of disease after a mean period of 18 months. Fourteen patients (61%) were without any evidence of disease after a mean of 32.5 months (range 3 to 86). The mitotic rate correlated weakly (P = .042) with a poor outcome, but none of the other factors showed a significant correlation with the prognosis.

CONCLUSION

MECs of the salivary glands have a relatively high recurrence rate and metastasis rate and a long period of survival with tumor. A combination of pathologic features and various immunohistochemical indexes are crucial for the accurate diagnosis of MECs. Extensive excision is the favorable choice for treating MECs, and suprahyoid lymph node dissection is recommended when the submandibular gland is involved.

Clear cell myoepithelioma of palate with emphasis on clinical and histological differential diagnosis

Myoepitheliomas account for less than 1% of all salivary gland tumors and mostly occur in the parotid gland and palate. A 58-year old male patient reported to the Outpatient Department of PMS College of Dental Science and Research (Kerala, India) with a slow growing painless swelling on the palate for 4 years. Pleomorphic adenoma, basal cell adenoma, myoepithelioma, cyst adenoma, lipoma, neurofibroma, neurilemmoma and leiomyoma were considered. Histopathology revealed a thinly encapsulated tumor composed mainly of sheets of clear cells mixed with cells having eosinophilic cytoplasm. Histopathological differential diagnosis included pleomorphic adenoma, oncocytoma, oncocytic hyperplasia, sebaceous adenoma, malignant salivary gland neoplasms and metastatic lesions from kidney and thyroid. Myoepitheliomas mostly occur in the parotid gland and palatal region and various histological types of myoepithelioma are described. Myoepitheliomas of the palate are rare with clear cell variant even rarer.

Myoepithelioma of the soft palate: a case report

Myoepitheliomas are rare benign tumors of myoepithelial cell origin, most commonly seen in parotid gland. These tumors are also reported in oral cavity, soft palate being the most common site of involvement. Imaging findings are nonspecific, and histopathology is necessary to differentiate from other tumors. Our case showed mildly enhancing well-circumscribed mass in soft palate with histological findings consistent with myoepithelioma. The aim of this case report is to increase the awareness about this rare benign tumor regarding its morphological, histopathological, and radiological features along with its possible differential diagnosis.

Establishment and characterization of METON myoepithelioma cell line derived from human palatal myoepithelioma: apical reference to the diverse differentiation potential

Myoepithelioma is an extremely rare condition that accounts for 1–1.5 % of salivary gland tumors. It was formerly regarded as a subtype of pleomorphic adenoma, in which myoepithelial structural components predominated, but was listed as a separate disease entity in the 1991 World Health Organization classification (Seifert in Histological typing of salivary gland tumours. Springer, Berlin, 1991). Its histology is highly varied and recurrence is frequent (El-Naggar et al. in J Larygol Otol 103:1192–1197, 1989), with cases of malignant transformation having been reported (Seifert in Histological typing of salivary gland tumours. Springer, Berlin, 1991; Barnes et al. in Pathology and Genetics of head and neck tumours. IARC Press, Lyon, 2005), making this a difficult tumor to control in many cases. This is thought to be due to the multiple differentiation potential of myoepithelial cells, but the details are unknown. There have been a number of reports of the establishment of cell lines (Shirasuna et al. Cancer. 45:297–305, 1980; Jaeger et al. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 84:663–667, 1997), but numerous points remain unclear. We established a myoepithelial cell line designated METON, and investigated its characteristics. METON consists of cells with two different morphologies: spindle-shaped cells and epithelial-like cells. Then. we also used single-cell cloning method to establish various subclones (epithelial-like, spindle-like, and mixed epithelial-like/spindle-like cell lines). Among these, pluripotency markers were expressed by the mixed epithelial-like/spindle-like cell lines. The newly established cell line expressing these pluripotency markers will be extremely useful for elucidating the diverse histologies of salivary gland tumors.

Benign breast myoepithelioma

Myoepithelioma of the breast is very rare. Breast myoepithelioma can develop in women from their early 20s right up to their 80s, but it is most common in women over 50. We report a case of 20-year-old female, who presented with a well-defined breast lump of 3 × 3 cm in size. Fine needle aspiration was performed. The cytological findings revealed good cellularity comprising monomorphic loosely cohesive sheets of plasmacytoid, round to polygonal cells with round to ovoid eccentrically placed nuclei, finely dispersed chromatin, and moderate amount of cytoplasm. On the basis of cytological findings, a diagnosis of benign myoepithelioma (plasmacytoid type) was made which was confirmed on histopathologic examination. The breast is a very rare localization for this type of tumor. The benign character of the disease in conjunction with its slow progression could delay its detection and diagnosis. A detailed pathology examination is a prerequisite for avoidance of misleading diagnosis.

Rapid-developed primary malignant myoepithelioma in the cavernous sinus: a case report

Background

Malignant myoepithelioma is a relatively rare malignant tumor occurring most frequently in the salivary glands. A few isolated cases have been described in other locations, including soft tissue, bone, lung, bronchus, oral cavity, nasopharynx, larynx, and maxillary sinus. Malignant myoepithelioma, however, is uncommonly involved within the cavernous sinus. To the best of our knowledge, this is the first report of malignant myoepithelioma arising from within the cavernous sinus.

Case presentation

Herein, we report a case of a 48-year-old woman who presented a 1-month history of diplopia and blepharoptosis as well as radiological evidence of a rapidly developing cavernous sinus tumor. The patient underwent a trans-sphenoidal biopsy and a histological diagnosis indicated a malignant myoepithelioma. After diagnosis, the tumor grew rapidly and her clinical condition deteriorated progressively. Therefore, a pterional craniotomy with partial tumor removal was performed. The patient’s clinical state was worsened, and she died two months after the initial operation. Because the malignant myoepithelioma could not be traced to an organ of origin, other than the cavernous sinus, this case was diagnosed as a primary intracranial malignant myoepithelioma.

Conclusion

The purpose of presenting this case report is to raise awareness among clinicians to consider malignant myoepithelioma as a differential diagnosis when a cavernous sinus mass is identified. Furthermore, an ideal management strategy for malignant myoepithelioma is not known and the prognosis seems to be unfavorable; therefore, more cases are needed to enhance our knowledge of the diagnosis, treatment, and prognosis of this rare intracranial lesion.

Myoepithelioma of the upper lip

Myoepithelioma is a rare form of salivary gland tumor composed entirely of myoepithelial cells. This tumor was formerly considered to be a subtype of pleomorphic adenoma; however, in the 1991 World Health Organization classification, it is listed as an independent entity. The most favorable site of occurrence of myoepithelioma is the parotid gland. Here, we report an extremely rare case of myoepithelioma of the upper lip. A 56-year-old woman presented with a painless mass on her upper lip. Magnetic resonance imaging revealed a 23 mm × 18 mm well-defined ovoid tumor. A benign minor salivary gland tumor was clinically suspected, and the patient underwent complete resection of the tumor under general anesthesia. The tumor was histopathologically diagnosed as a benign myoepithelioma of the minor salivary gland. Immunohistochemically, the tumor cells were positive for S-100 protein, AE1/AE3, CAM5.2, CK7, vimentin, and calponin, confirming the morphologic diagnosis of myoepithelioma. The patient's postoperative clinical course was uneventful, and satisfactory results were obtained both functionally and esthetically. To the best of our knowledge, this is the sixth case of myoepithelioma of the upper lip reported in English-language research.

Unusual myoid, perivascular, and postradiation lesions, with emphasis on atypical vascular lesion, postradiation cutaneous angiosarcoma, myoepithelial tumors, myopericytoma, and perivascular epithelioid cell tumor

In recent years, a number of new soft tissue tumor entities have been described that occur in the skin only, or that also occur in other sites but form clinically and pathologically distinct subsets when arising in the skin and subcutaneous tissue. These include a variety of mesenchymal lineages and have variable malignant potential, although superficial malignant soft tissue tumors generally have a more favorable outcome than their more deeply located counterparts. This article reviews the clinical and pathologic features and differential diagnoses of atypical vascular lesion, postradiation cutaneous angiosarcoma, myoepithelioma, myopericytoma, and perivascular epithelioid cell tumor.

Clear cell myoepithelial carcinoma in the base of the tongue: Case report and review of the literature

Clear cell myoepithelial carcinoma is a very rare disease which develops primarily in the parotid gland. To date, only 17 cases of clear cell myoepithelial carcinoma have been reported worldwide. Among them, only three cases developed in the minor salivary gland in the oral cavity. No cases developed in the base of the tongue. Here, we report a new case of clear cell myoepithelial carcinoma that developed in the tongue base of a 52-year-old female patient. A mass was discovered on the left side of the tongue base. We successfully removed the mass through suprahyoid pharyngotomy approach. The light microscopy examination and various immunohistochemical stainings revealed clear cell myoepithelial carcinoma. During a two year follow-up period, there was no recurrence or local or distant metastasis.

A Rare Case of Myoepithelioma around the Left Orbit

Myoepithelioma is a rare neoplasm of the salivary glands, generally occurring in the parotid gland and less often in the mi-nor accessory salivary glands of the oral cavity. It is known to be a rare entity occurring at unusual locations, which makes it difficult to diagnose. Such a rare case of myoepithelioma in salivary glands present at an unusual location around the left orbit is presented here.

INI1-deficient tumors: diagnostic features and molecular genetics

Significant progress has been made in understanding the molecular genetic alterations involved in sarcomagenesis. Cytogenetic and molecular studies have identified nonrandom genetic abnormalities, including tumor suppressor gene inactivation. Mutations, deletions, and other somatic alterations in the tumor suppressor gene INI1 (hSNF5; SMARCB1), which encodes a subunit of the SWI/SNF chromatin remodeling complex, were first described in the malignant rhabdoid tumor of infancy. Since then, INI1 has also been implicated in the pathogenesis of additional tumor types including renal medullary carcinomas and epithelioid sarcomas and a subset of epithelioid malignant peripheral nerve sheath tumors, myoepithelial carcinomas, and extraskeletal myxoid chondrosarcomas. As varied as this group appears, they all show loss of INI1 protein expression, a propensity for rhabdoid cytomorphology, and sometimes other overlapping immunohistochemical and histologic findings. We will review the clinicopathologic features of these tumor types and emphasize the clinical utility of INI1 immunohistochemistry in differential diagnosis.

Myoepithelioma of the soft palate: a case report giving special attention to the differential diagnosis

BACKGROUND

Myoepitheliomas are rare tumours that may generally arise from the minor or major salivary glands. The differential diagnosis of this tumour should be performed along with several benign and malignant soft tissue neoplasms. The present case report describes an asymptomatic mass that arose in the soft palate of 42 year old black woman with duration of the six months.

METHODS

An incisional biopsy of soft palate lesion was carried out and submitted for histological evaluation under the clinical hypothesis of salivary gland tumour. To confirm the myoepithelial nature of neoplastic cells the immunohistochemical reactions for smooth-muscle actin, cytokeratins and S100 were performed.

RESULTS

The histological examination revealed the presence of tumour originating from a minor salivary gland and covered by a stratified squamous oral epithelium. The tumour cells were arranged in order to form a myxoid pattern and, individually, small and/or medium spindle-shaped cells with predominantly round or ovoid nuclei, as well as epithelioid and plasmocytoid cells were noted. The stroma was myxomatous and no ductal or syringomatous epithelial structures were observed. Following the histological and immunohistochemical diagnosis of myoepithelioma, the lesion was surgically removed. After the surgery, a follow-up of one year showed no signs and symptoms of reccurrence.

CONCLUSIONS

The myoepithelioma should be carefully distinguished from the other soft tissue tumours, especially those arising from salivary glands, such as pleomorphic adenoma and adenoid-cystic carcinoma.

Myoepithelioma of the hand and carpal tunnel: An unusual cause of median nerve compression

Myoepitheliomas are rare tumors increasingly recognized to occur in the soft tissues. Although the hand and carpal tunnel are exceptional locations, the presence of these lesions in such sites constitutes a potential cause of debilitating symptoms. We report the case of a patient with severe pain secondary to median nerve compression and displacement of flexor tendons caused by a rapidly growing myoepithelioma. This is the first sonographic description of this tumor producing carpal tunnel syndrome and disabling pain. High-resolution sonography allowed evaluation of gross tumor morphology and real-time assessment of its interactions with surrounding structures.

Benign myoepithelioma of the lung - a case report and review of the literature

Introduction

Benign myoepithelioma is extremely rare in the lung, to the best of our knowledge; only five cases have been reported in the literature.

Case Report

An 18-years woman complained from tiredness and fever during four months. Laboratory findings and fibroscopies were normal. CT of the thorax demonstrated a nodule in the left segment of the Fowler. Left inferior lobectomy was performed comporting a firm nodule of 25 mm, lifting the bronchial mucous membrane. Histologically, there was a proliferation of small cells of a plasmocytoid-type, with a predominantly whorled pattern. No mitotic activity or necrosis was seen in the tumor. Immuhistochemically, the tumor cells positive for smooth muscle actin, vimentine, and S100 protein. They were negatives for cytokeratine, chromogranine and HMB45. The diagnosis of benign myoepithelioma of the lung is so confirmed. The patient recovered well at 6 months follow-up.

Conclusion

Benign myoepithelioma is a rare pulmonary neoplasm distinct from pleomorphic adenoma, which should be considered in the differential diagnosis of lung nodules.

Soft tissue mixed tumor of the hand

Mixed tumors are relatively common in the skin and salivary glands, but extremely rare in soft tissues, often resulting in diagnostic problems. The occurrence of these tumors in the hand is especially limited. In this article we report the clinical, radiological, and histological features of a mixed tumor of the hypothenar region of the right hand.

Soft tissue mixed tumor of the hand

Mixed tumors are relatively common in the skin and salivary glands, but extremely rare in soft tissues, often resulting in diagnostic problems. The occurrence of these tumors in the hand is especially limited. In this article we report the clinical, radiological, and histological features of a mixed tumor of the hypothenar region of the right hand.

A rare myoepithelioma of the sinonasal cavity: case report

Myoepithelioma is a rare benign neoplasm. Pure accounting for less than 1% of all salivary gland tumors. Only three cases of sinonasal myoepithelioma have been reported in the literature. Diagnosis of myoepithelioma through light microscopy is possible and immunohistochemistry is done to facilitate the diagnosis. The lesion is so rare that there are no specific indications/guidelines for its treatment. We report to you a rare case of sinonasal myoepithelioma in a 57 year old Asian female.

Myoepitheliomas are rare tumours that account for only about 1% of all salivary gland tumors. Most are benign, but some can be malignant. Only three cases of sinonasal myoepithelioma have been reported in the literature so far.