Effect of Primary Site and Treatment Modality of Patients With Head and Neck Myoepithelial Carcinoma on Survival.

AIM: Epidemiological evidence on myoepithelial carcinoma is rare. This study aimed to investigate the effect of tumor primary site and treatment modality on survival in patients with head and neck myoepithelial carcinoma. MATERIALS AND METHODS: Data on adult patients diagnosed with head and neck myoepithelial carcinoma between 2000 and 2019 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Uni- and multivariable Cox proportional hazard models were utilized to evaluate the effects of different tumor primary sites and treatment modalities on overall survival (OS) and cancer-specific survival (CSS), and expressed as hazard ratio (HR) and 95% confidence interval (CI). RESULTS: A total of 415 patients were enrolled. No significant differences in OS and CSS were found between different tumor primary sites (P > 0.05). Compared with partial excision, patients with total excision (HR = 1.65, 95%CI: 1.12-2.42) (partial or total removal of the organ in which the tumor is located and complete removal of the tumor) or no surgery (HR = 3.52, 95%CI: 2.05-6.03) had worse OS. Compared with surgery only, patients with radiotherapy only had poorer OS (HR = 4.69, 95%CI: 2.32-9.46) and CSS (HR = 6.72, 95%CI: 2.59-17.46), while no significant differences in OS (P = 0.120) and CSS (P = 0.847) were found among patients who received surgery combined with radiotherapy. In patients with AJCC III/IV, patients with radiotherapy only (HR = 4.51, 95%CI: 1.61-12.62) had poorer OS compared to those with surgery only, whereas patients who received surgery combined with radiotherapy had better OS (HR = 0.50, 95%CI: 0.29-0.89). CONCLUSION: The tumor primary site may not affect the prognosis of patients with myoepithelial carcinoma, while the effect of treatment modality on prognosis is related to the primary site and stage of the tumor.

Progresión locorregional de carcinoma mioepitelial de la mama postratamiento quimiorradioterápico. Resección y cobertura con colgajo de avance / Locoregional progression of myoepithelial carcinoma of the breast after chemotherapy and radiotherapy. Resection and coverage with advancement flap

El carcinoma mioepitelial de la mama es un tumor infrecuente, con pocos casos descritos en la literatura, por lo que su diagnóstico es difícil y su tratamiento un desafío que incluye el diseño de colgajos locales. Presentamos un caso clínico de carcinoma mioepitelial de mama con progresión locorregional tras quimioterapia y radioterapia, así como una revisión de la literatura que nos permiten establecer un diagnóstico definitivo y un tratamiento óptimo oncológico y quirúrgico con reconstrucción de este tumor.(AU)

Myoepithelial carcinoma of the breast is an uncommon tumour with few cases reported in the literature. Consequently, it is a diagnostic and therapeutic challenge. Treatment includes the design of local flaps. We present a case of myoepithelial carcinoma of the breast with locoregional progression after chemotherapy and radiotherapy. We also provide a review of the literature, allowing us to establish a definitive diagnosis and optimal oncological and surgical treatment with reconstruction of this tumour.(AU)

Clinical and pathological analysis of 10 cases of salivary gland epithelial-myoepithelial carcinoma.

Epithelial-myoepithelial carcinoma (EMC) is a rare neoplasm of the salivary glands. The aim of this study is to review and evaluate clinicopathological features and treatment of EMC of salivary gland for better sensitivity and specificity of the diagnosis.The clinical and pathological data of the 10 salivary gland EMC cases from 2008 to 2017 were analyzed.Six cases of EMC were diagnosed to be originated from parotid gland and 4 cases were from the minor salivary gland including palate, tongue, and oropharynx. Seven cases were performed radical surgery and 3 cases had radiotherapy postoperation, 2 cases had a local recurrence. The follow-up period was 4 to 104 months and the survival rate was 100%. Histopathology showed the tumors had a dominant prototypical biphasic tubular structure consisting of inner, cuboidal ductal cells and an outer layer of clear, myoepithelial cells, which grew infiltratively. The immunohistochemistry (IHC) showed the marker proteins CK, S-100, CD117, and Calponin were strongly positive in most EMC.EMC is a rare and low-grade malignant tumor with good overall survival but relatively high tendency for local recurrence. Surgery is the priority choice for EMC therapy. Complete surgical excision and negative margins are necessary for good prognosis. Imaging techniques should be used to assess the neck dissection and it is unclear whether adjuvant radiotherapy is beneficial. To ensure the sensitivity and specificity of the EMC diagnosis, we should perform both pathological and IHC analysis.

Myoepithelial Carcinoma of Urinary Bladder in a Pediatric Patient. A Case Report.

Myoepithelial carcinoma is a rare pathological variant, usually expressed in salivary gland. This case report describes a case of pediatric myoepithelial carcinoma in the urinary bladder. A 4-year-old male patient was admitted to a specialized hospital in Lima, Peru for hematuria. A CT scan showed a tumor lesion in the bladder wall, and biopsy revealed myoepithelial carcinoma of urinary bladder. Six courses of chemotherapy + partial cystectomy + radiotherapy was completed. The treatment was defined based on the pathological variant and the tumor location. The patient is currently at 2 years of disease-free survival.

Misinterpreted Myoepithelial Carcinoma of Salivary Gland: A Challenging and Potentially Significant Pitfall.

Myoepithelial carcinoma (MECA) is an underrecognized challenging entity with a broad morphologic spectrum. Misinterpreting MECA is not uncommon as distinguishing it from its mimics, especially cellular myoepithelial-rich pleomorphic adenoma (PA), can be difficult. We described 21 histologically challenging cases of MECAs (16 MECA ex-PA and 5 MECA de novo). All MECAs ex-PA were intracapsular or minimally invasive except for 3 cases. Eighteen (86%) were initially misinterpreted as benign neoplasms, including PA (10), atypical PA (5), and myoepithelioma (3). The remaining 3 were initially diagnosed as malignant (MECA ex-PA) but were histologically challenging. Histologic features that were found most helpful in recognizing the malignant nature of MECA included: uniformly cellular myoepithelial proliferation with an expansile nodular lobulated pattern (all cases) and alternate hypocellular and hypercellular zonal distribution (76% of cases). Among the 16 MECA patients with follow-up, 14 (87.5%) progressed: 10 developed local recurrence and 5 distant metastases. In contrast, only one of 33 patients with cellular PA (control group) recurred locally. Ten of the 14 MECAs that progressed were MECA ex-PA, and 12 (85%) had an initial benign diagnosis. Two patients with MECA ex-PA died of their disease; one had an initial diagnosis of PA. MECA is a histologically challenging entity that closely mimics PA and seems to carry a significant risk of recurrence. Areas of clonal appearing cellular myoepithelial growth with an expansile nodular lobulated pattern and zonal cellular distribution distinguish the majority of MECAs and may serve as useful diagnostic histologic features to differentiate MECA from its benign mimics.

A Rare Case of an Intracardiac Myoepithelial Carcinoma in an Infant.

Myoepithelial carcinomas (MC) represent aggressive tumors that occur in a myriad of ages and anatomic locations. The rarity and histologic similarity with other tumors make them difficult to diagnosis. We report an extremely rare case of a right ventricular outflow tract mass identified to be an intracardiac MC in a 4-month-old male infant. Pathology revealed an EWS-KLF15 translocation. Treatment included gross total resection and intensive chemotherapy. Recurrent cardiac mass with brain metastasis was seen 16 months after primary diagnosis. We describe the rarity of intracardiac MC in pediatric patients and the challenges encountered in the multimodal management of this patient.

Myoepithelioma of Soft Tissues: A Single Institution Retrospective Case Series.

BACKGROUND: Myoepithelioma of the soft tissues is a rare entity and little is known about how best to manage locally recurrent and high-grade disease. Here, we retrospectively examined outcomes of surgery, chemotherapy, and radiation therapy (RT) for treatment of low-grade and high-grade myoepithelioma of soft tissues. METHODS: We reviewed 20 cases of myoepithelioma of soft tissues seen at Mayo Clinic between 1994 and 2014. The effect of histologic grade and therapies received on relapse and survival were assessed. RESULTS: We identified 13 patients with low-grade disease and 7 patients with high-grade disease. We found that low-grade disease was frequently effectively managed with surgical resection alone, whereas high-grade disease frequently metastasized and was often fatal. The 5-year event-free survival was 88% (confidence interval, 46%-98%) for low-grade disease versus 36% (confidence interval, 7%-75%; P=0.04) for high-grade disease. The relapse rate in low-grade disease was 29% at 5 years versus 64% (P=0.04) in high-grade disease. No significant responses to chemotherapy were noted, however, excellent responses to perioperative RT were seen. CONCLUSIONS: Surgery continues as the primary modality of treatment for myoepithelioma of soft tissues. Our study did not show a clear benefit of chemotherapy in the metastatic disease setting, but supports the use of perioperative RT in the management of high-grade disease; further investigation is warranted.

Salivary gland epithelial neoplasms in pediatric population: a single-institute experience with a focus on the histologic spectrum and clinical outcome.

Salivary gland epithelial neoplasms are rare in children and adolescents, with only a handful of large series having been published. A retrospective study was conducted for 57 cases in patients 20 years or younger. The tumors were located in the parotid (n=36), submandibular gland (n=7), and minor salivary glands (n=14). Nineteen (33%) tumors were pleomorphic adenoma, whereas the remaining (67%) were malignant. The histologic types of carcinomas were mucoepidermoid carcinoma (MEC, n=19, 33%), acinic cell carcinoma (n=7, 12%), adenoid cystic carcinoma (n=6, 11%), secretory carcinoma (mammary analogue) (SC, n=4, 7%), and myoepithelial carcinoma (n=2, 4%). Ninety-three percent (13/14) of the minor and 58% (25/43) of the major salivary gland tumors were malignant. A 7-year-old girl (2%) with a high-grade MEC died from her disease because of uncontrollable locoregional recurrence. Seven patients (16%) developed recurrence including 2 distant metastases from adenoid cystic carcinoma and 6 locoregional recurrences (2 pleomorphic adenomas, 1 SC, 1 myoepithelial carcinoma, 1 adenoid cystic carcinoma, and 1 MEC). The following parameters were associated with decreased disease-free survival in malignant tumors: elevated mitotic index of >4/10 high-power fields (log-rank test, P<.001), and advanced American Joint Committee on Cancer pT (P=.029) and pN stage (P<.001). In conclusion, myoepithelial carcinoma and SC can occur in the pediatric population and should be considered in the differential diagnosis. Salivary gland malignancies in children appear to have better clinical outcome, associated with a 10-year recurrence-free survival rate of 74% and a 10-year disease-specific survival of 94%.

Myoepithelial carcinoma with RB1 mutation: remarkable chemosensitivity to carcinoma of unknown origin therapy.

BACKGROUND: Myoepithelial carcinoma of soft tissue is a rare, malignant neoplasm that is morphologically and immunophenotypically similar to its counterpart in salivary gland. It demonstrates myoepithelial differentiation, possessing both epithelial and myogenic characteristics. Thought to be chemotherapy insensitive, the optimal treatment regimen of this tumor has yet to be established and only a select few cases in the literature discuss treatment efficacy in detail. CASE PRESENTATION: Here we present a case of a young adult with metastatic myoepithelial carcinoma with an initial excellent response to systemic therapy utilizing carboplatin and paclitaxel with continued complete response after 3 years. The patient also underwent complete surgical excision and received adjuvant radiation to the primary site of disease. Exome sequencing revealed an inactivating mutation in RB1 which we believe to be the first such mutation to be reported in this cancer type. CONCLUSIONS: Given increasing evidence suggesting RB1 loss is associated with responsiveness to conventional chemotherapies, particularly platinum-based regimens, we hypothesize that this genetic feature predisposed chemosensitivity in our patient's tumor.

Invasive myoepithelial carcinoma ex pleomorphic adenoma of the major salivary gland: two case reports.

BACKGROUND: Myoepithelial carcinoma (MEC) is a rare salivary gland tumor. Its long-term prognosis remains unknown because of the paucity of reported cases with long-term follow-up. Although some case series exist, the clinical features of MEC vary considerably depending on the site of origin. Therefore, accumulation of these rare cases is important. CASE PRESENTATION: Case 1: An 89-year-old man presented with a 10-year history of a mass originating from the right parotid gland and involving the neck. The mass grew rapidly for 3 months, reaching approximately 8 cm. There was no facial paralysis. MEC ex pleomorphic adenoma (PA) was suspected. Superficial parotid gland resection was performed in 2013; the tumor grade was pT3N0M0, and the resection margins were free of carcinoma. Because of several high-risk factors for metastasis (i.e., invasive carcinoma ex PA, high MIB1 index, and mutant p53 protein positivity), radiotherapy and chemotherapy were recommended as adjuvant therapy. Although the patient refused adjuvant therapy, he was recurrence-free at 36 months after surgery. Case 2: A 54-year-old woman presented with a >10-year history of a right submandibular mass, which grew rapidly for 1 year, reaching approximately 6 cm. Preoperative diagnosis was PA of the right submandibular gland. Submandibular gland resection was performed in 2013. Pathological analysis revealed invasive MEC ex PA, pT3N0M0; in addition, the carcinoma portion had an extra capsule and had invaded the platysma muscle close to the margin. An MIB1 index of 40 % and mutant p53 protein positivity indicated a high risk for metastasis. Additional resection and right neck dissection revealed no residual carcinoma. The patient refused adjuvant chemotherapy. One year after surgery, metastasis to the right pulmonary hilar node and both lungs were detected. Chemotherapy prevented recurrent growth of the lesion and extended survival. The patient was alive with cancer 30 months after the first surgery. CONCLUSIONS: High expression of the Ki67 labeling index might reflect prognosis of these cases. Chemotherapy for distant metastasis was effective, as expected. Further accumulation of cases and long follow-up data are needed to elucidate the pathophysiology and prognosis of MEC ex PA.

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.

Patterns of lymph node metastasis of parotid cancer.

OBJECTIVE: To define the incidence and pattern of spread of lymph node metastasis from parotid cancers and to clarify the risk factors and appropriate extent of neck dissection (ND) for individual patient with parotid cancer. METHODS: A total of 72 patients with parotid gland cancer treated by surgery between 1994 and 2013 were analyzed retrospectively by reference to medical records. In line with our protocol, patients with clinically positive lymph nodes and/or cT3/T4 disease were generally selected to undergo ND. RESULTS: Pathological examinations revealed mucoepidermoid carcinoma in 23 patients, carcinoma ex pleomorphic adenoma in 11, adenoid cystic carcinoma in 9, salivary duct carcinoma in 9, acinic cell carcinoma in 8, squamous cell carcinoma in 5, adenocarcinoma NOS in 4, epithelial myoepithelial carcinoma in 2, and basal cell carcinoma in 1. Thirty-three patients underwent neck dissection: modified radical ND (MRND) in 13, and elective ND (END) in 20. Postoperative RT (PORT) was performed in 33 patients. Among 13 cN+ patients, 10 were pN+ and lymph node metastasis was distributed mainly in levels I, II, III and V. Among 59 cN- patients, clinical T1, T2, T3 and T4 classifications accounted for 10, 24, 10 and 15 patients, respectively. The incidence of occult lymph node metastasis was 22%. Occult lymph node metastasis was mostly seen in the intraparotid, levels I and II of patients with cT4 disease. Among the ND group, 12 necks were pathologically negative for cancer (pN0). Relapse of neck lymph node metastasis occurred only in two patients treated by MRND with pathologically positive lymph nodes (pN+). These patients developed local and distant metastasis within 1 year after neck lymph node recurrence, and subsequently died of the cancer. pN+ was found in 19/30 high grade (63%), 1/10 intermediate grade (10%), and 3/32 low grade (9.4%). Among 33 patients who received PORT, only 1 patient relapsed neck lymph node. CONCLUSION: For patients with clinically positive lymph nodes, ipsilateral modified radical neck dissection (levels I-V) is recommended. Elective neck dissection is strongly recommended for patients with T3N0 or T4N0 disease, and the extent of ND should include at least level I/II. PORT for patients with high-risk features may improve the outcome of good neck control.

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.

[Analysis of the diagnosis and treatment of myoepithelial carcinoma of the parotid gland: report of 17 cases].

OBJECTIVE: Myoepithelial carcinoma (MC) is a rare malignant neoplasm of the salivary gland. The aim of this study was to analyze the diagnosis, treatment and prognosis of MC of the parotid gland. METHODS: The clinicopathological data of 17 cases of MC of the parotid gland treated in our hospital from 1999 to 2013 were analyzed retrospectively. Of all the 17 patients, 9 cases received radical surgery only, 5 cases received postoperative radiotherapy, 2 cases received preoperative radiotherapy, and one case received chemotherapy. The survival rate was calculated by Kaplan-Meier analysis. RESULTS: Among the 17 patients, 11 patients had post-operative recurrence (11/17, 64.7%), Of these 11 cases, 5 cases (45.5%) had recurrence within one year after the first operation. During the follow-up for 12-180 months (median 50 months), six cases died (two patients died of distant metastases and 4 cases died of local recurrence). The overall 1-year, 2-year and 5-year survival rates were 94.1%, 74.2% and 64.9%, and the overall 1-year, 2-year and 5-year recurrence-free survival rates were 70.6%, 48.1% and 40.1%, respectively. CONCLUSIONS: Radical surgery is the main treatment modality for myoepithelial carcinoma of the parotid gland. For the patients with extensive lesions or after palliative surgery, adjuvant radiotherapy or chemotherapy might be helpful. However, its therapeutic efficacy remains to be proved.

Epithelial-myoepithelial carcinoma of lacrimal gland from an ex pleomorphic adenoma.

A 47-year-old man with a history of recurrent pleomorphic adenoma of the right lacrimal gland presented with rapid onset of a swelling in the right orbit. Initial imaging with CT showed that the swelling was grossly involving the extraocular muscles. Hence we had a suspicion of malignant transformation, so a radical approach in the form of right orbital exenteration with anterior skull base resection and temporalis muscle reconstruction was taken. Postoperative histology revealed epithelial-myoepithelial carcinoma, with immunopositivity for epithelial and myoepithelial components. Adjuvant radiation of 60 Gy was given with three-dimensional CT-based planning. This case portrays the importance of adjuvant treatment in recurrent pleomorphic adenoma and chance of malignant transformation in rare histologies.

Epithelial-Myoepithelial Carcinoma of the Salivary Glands: An Analysis of 246 Cases.

OBJECTIVE: Epithelial-myoepithelial carcinoma (EMC) is a rare neoplasm of the salivary glands. In this study, we aim to examine the demographic, clinicopathologic, and survival features of EMC using a population-based approach. STUDY DESIGN AND SETTING: Retrospective cohort study. SUBJECTS AND METHODS: The Surveillance, Epidemiology, and End Result (SEER) database (1973-2010) was queried for EMC of the major salivary glands. Data were analyzed with respect to various demographic and clinicopathologic factors. Survival was analyzed using the Kaplan-Meier and Cox proportional hazards models. RESULTS: In total, 246 cases were available for frequency analysis and 207 for survival analysis. Mean ± SD age at diagnosis was 63.8 ± 15.4 years. EMC affected females more frequently (57.3%). Distant metastases were present at diagnosis in only 4.5% of cases. Overall disease-specific survival (DSS) at 60, 120, and 180 months was 91.3%, 90.2%, and 80.7%, respectively. Patients with low-grade histology had significantly better survival at 180 months relative to those with high-grade tumors (90.6% vs 0.0%, P = .0246). When stratified by tumor size, patients with lesions >4 cm had the worst survival at 180 months (58.8%, P = .0003). All but 9 of the 207 cases available for survival analysis underwent surgery. A total of 85 patients (41.1%) received radiotherapy in addition to surgery. No survival benefit was noted for patients who received radiotherapy compared with those who did not (P = .4832). CONCLUSION: This report represents the largest series of EMC to date. Despite being regarded as a low-grade, indolent tumor, a significant fraction of our cohort underwent radiotherapy in addition to surgery, with no apparent added survival benefit.

Risk Factors and Prognosis for Myoepithelial Carcinoma of the Major Salivary Glands.

BACKGROUND: The clinical behavior and treatment outcomes of salivary gland myoepithelial carcinoma have yet to be clearly defined. The current study investigated risk factors and prognoses for this tumor. METHODS: A retrospective review of the medical records for 32 patients with myoepithelial carcinoma of the major salivary glands was performed. Their clinical parameters were assessed to identify correlations with local-regional recurrence, distant metastasis, and survival. RESULTS: The 5-year survival rate was 71 %. Of the reviewed patients, 41 % had local-regional recurrences, and 22 % had distant metastases. Age of 60 years or younger was a predictive factor for distant metastasis. Patients with neck lymph nodes clinically positive for carcinoma had shorter overall survival durations than those with nodes negative for carcinoma. CONCLUSIONS: Myoepithelial carcinoma of the major salivary glands is characterized by a high incidence of local-regional recurrence and distant metastasis. Adjuvant therapy is indicated for selected patients with high-risk disease.

Clear cell myoepithelial carcinoma of salivary glands showing EWSR1 rearrangement: molecular analysis of 94 salivary gland carcinomas with prominent clear cell component.

This study examines the presence of the EWSR1 rearrangement in a variety of clear cell salivary gland carcinomas with myoepithelial differentiation. A total of 94 salivary gland carcinomas with a prominent clear cell component included 51 cases of clear cell myoepithelial carcinomas de novo (CCMC), 21 cases of CCMCs ex pleomorphic adenoma (CCMCexPA), 11 cases of epithelial-myoepithelial carcinoma (EMC), 6 cases of EMC with solid clear cell overgrowth, and 5 cases of hyalinizing clear cell carcinoma of minor salivary glands. In addition, 10 cases of myoepithelial carcinomas devoid of clear cell change and 12 cases of benign myoepithelioma were included as well. All the tumors in this spectrum were reviewed, reclassified, and tested by fluorescence in situ hybridization (FISH) for the EWSR1 rearrangement using the Probe Vysis EWSR1 Break Apart FISH Probe Kit. The EWSR1 rearrangement was detected in 20 of 51 (39%) cases of CCMC, in 5 of 21 (24%) cases of CCMCexPA, in 1 of 11 (9%) cases of EMC, and in 4 of 5 (80%) cases of hyalinizing clear cell carcinoma. The 25 EWSR1-rearranged CCMCs and CCMCexPAs shared similar histomorphology. They were arranged in nodules composed of compact nests of large polyhedral cells with abundant clear cytoplasm. Necrosis, areas of squamous metaplasia, and hyalinization were frequent features. Immunohistochemically, the tumors expressed p63 (96%), cytokeratin CK14 (96%), and S100 protein (88%). MIB1 index varied from 10% to 100%, with most cases in the 20% to 40% range. Clinical follow-up information was available in 21 cases (84%) and ranged from 3 months to 15 years (mean 5.2 y); 4 patients were lost to follow-up. Ten patients are alive with no evidence of recurrent or metastatic disease in the follow-up period from 3 months to 15 years (mean 5 y), 3 patients are alive with recurrent and metastatic disease, and 8 died of disseminated cancer 9 months to 16 years after diagnosis (mean 6 y). Lymph node metastasis appeared in 5 patients within 5 months to 4 years after diagnosis (mean 22 mo), distant metastases were noted in 7 patients with invasion of orbit (2 cases), and in 1 case each metastasis to the neck soft tissues, liver, lungs, mediastinum, and thoracic vertebra was noted. We describe for the first time EWSR1 gene rearrangement in a subset of myoepithelial carcinomas arising in minor and major salivary glands. The EWSR1-rearranged CCMC represents a distinctive aggressive variant composed predominantly of clear cells with frequent necrosis. Most EWSR1-rearranged CCMCs of salivary glands are characterized by poor clinical outcomes.