Clinicopathological and survival profile of patients with salivary gland myoepithelial carcinoma: A systematic review.

OBJECTIVES: In this systematic review, we aimed to evaluate the clinicopathological and prognosis data of patients with salivary gland myoepithelial carcinoma. MATERIALS AND METHODS: MEDLINE/PubMed, Scopus, and Embase search was performed with the keywords "myoepithelial carcinoma" "malignant myoepithelioma," and "salivary glands." Primary salivary glands myoepithelial carcinoma that fulfilled the World Health Organization diagnostic criteria were included. The Joanna Briggs Institute tool was used to assess the risk of bias. RESULTS: Forty-three studies (71 patients) met the inclusion criteria. The patients showed a mean age of 56.4 ± 19.6 years with no sex predilection. The parotid was the most affected gland (49.3%). The tumor presented as an asymptomatic (65.1%) mass (84%). The most common histological findings were the presence of clear tumor cells (39.7%) and multinodular growth patterns (60.7%). Multivariate analysis showed plasmacytoid cell type (p = 0.010) and solid growth pattern (p = 0.003) were related to decreased disease-free survival. Surgery alone was the most used treatment (53.5%). Patients with a combination of treatments showed a longer disease-free survival (p = 0.049). The 2-year and 5-year overall survival rates were 67.5% and 46.1%, respectively. CONCLUSION: Salivary gland myoepithelial carcinoma showed no sex predilection, with a higher incidence in the parotid gland. Cell type, growth pattern, and treatment type may be related to a lower disease-free survival. Overall, salivary gland myoepithelial carcinoma presented low recurrence and metastasis rates. Registration and protocol: This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 checklist and registered in the International Prospective Register of Systematic Reviews (PROSPERO) database (CRD42022311512).

Spontaneous tumor regression following COVID-19 vaccination.

Vaccination against COVID-19 is critical for immuno-compromised individuals, including patients with cancer. Systemic reactogenicity, a manifestation of the innate immune response to vaccines, occurs in up to 69% of patients following vaccination with RNA-based COVID-19 vaccines. Tumor regression can occur following an intense immune-inflammatory response and novel strategies to treat cancer rely on manipulating the host immune system. Here, we report spontaneous regression of metastatic salivary gland myoepithelial carcinoma in a patient who experienced grade 3 systemic reactogenicity, following vaccination with the mRNA-1273 COVID-19 vaccine. Histological and immunophenotypic inspection of the postvaccination lung biopsy specimens showed a massive inflammatory infiltrate with scant embedded tumor clusters (<5%). Highly multiplexed imaging mass cytometry showed that the postvaccination lung metastasis samples had remarkable immune cell infiltration, including CD4+ T cells, CD8+ T cells, natural killer cells, B cells, and dendritic cells, which contrasted with very low levels of these cells in the prevaccination primary tumor and lung metastasis samples. CT scans obtained 3, 6, and 9 months after the second vaccine dose demonstrated persistent tumor shrinkage (50%, 67%, and 73% reduction, respectively), suggesting that vaccination stimulated anticancer immunity. Insight: This case suggests that the mRNA-1273 COVID-19 vaccine stimulated anticancer immunity and tumor regression.

Metastatic low-grade myoepithelial carcinoma of lung managed with low-dose external beam radiotherapy.

Myoepithelial tumor of lung is a rare tumor; the histopathological findings resemble the myoepithelial tumors of the salivary gland. Distinguishing low-grade nonmetastatic myoepithelial carcinoma from benign myoepithelioma can be challenging both radiologically and histomorphologically. We present a case report of a low-grade myoepithelial carcinoma of lung with contralateral lung metastasis which was treated with low-dose external beam radiotherapy.

Metastatic Epithelial-Myoepithelial Carcinoma in a Female Presenting with Neck Mass and Lytic Lesion in Acetabulum: A Diagnostic Challenge on Cytology.

Epithelial-myoepithelial carcinoma (EMC) is a rare, low-grade, malignant salivary neoplasm. Establishing an accurate cytological diagnosis is often challenging owing to its rarity, bland cytologic appearance and variable representation of cell populations in the smears. The diagnostic struggle is more so when the aspiration is from a metastatic site with an unknown primary, as in such cases the list of differential diagnoses expands further. A 58-year-old female presented with a low-back pain from last one month. On examination, she also had a level III, right cervical swelling for the last 20 years. Radiology revealed a lytic lesion in the left acetabulum. She had undergone surgery 35 years ago for a right-sided upper neck swelling, the medical records of which were not available. Fine needle aspiration (FNA) from the cervical swelling was performed. The smears were cellular and showed predominantly dispersed, round to polygonal tumor cells with mild pleomorphism, eccentric nuclei, coarse chromatin, occasional nucleoli and moderate cytoplasm with some showing vacuolations. The cell-block section revealed tumor cells arranged in the form of tubules lined by dual layer of tumor cells without any chondromyxoid stroma. On immunocytochemistry, the luminal cells showed positivity for CK7 (epithelial marker) and the abluminal cells showed positivity for p63 (myoepithelial marker). Based on these features, a final diagnosis of metastatic epithelial-myoepithelial carcinoma was rendered. The present report highlights the characteristic cytomorphological and immunocytochemical features of EMC and reiterates the diagnostic accuracy of FNAC for diagnosis of such challenging cases.

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.

Metastasis of malignant myoepithelial carcinoma to the brain.

Myoepithelial tumours are a rare form of salivary gland neoplasm and intracranial metastases have rarely been described. The authors present the case of a 61-year-old patient with a history of primary myoepithelial carcinoma of the right foot. Metastases were found in the third ventricle, left temporal lobe and right frontal lobe. The third ventricular and left temporal lobe tumours were resected in a two-stage operation. Pathology of the third ventricular lesion was most consistent with metastasis. MRI of the spine 2 weeks after his operation revealed an intradural mass with several lesions in the lumbar thecal space suggesting further metastases. The patient succumbed to his disease 2 months after his two-stage operation and 5 years after his initial diagnosis. This appears to be the first case in the literature of multiple primary myoepithelial carcinoma metastases to the brain. Further information is needed to provide diagnostic and therapeutic recommendations.

Acral Metastasis of the Fingers: Report of 2 Cases. / Metástasis digital acral: presentación de 2casos clínicos.

Cutaneous metastases appear in 0.6% to 10.4% of malignant tumors and account for 2% of all cutaneous tumors. Metastasis to the skin may arise from progression of a known primary tumor or provide the first sign of an unsuspected one. Acral metastases are particularly unusual. Most derive from bone tumors. Clinical signs vary and the lesions generally resemble infection or inflammation, leading to diagnostic delays. When metástasis involves the fingers, the primary tumor is usually lung carcinoma. In contrast, toe involvement usually derives from a tumor in the genitourinary tract. A pathologic diagnosis in these cases is necessary and will suggest the location of the primary tumor. We report 2 cases of metástasis to the fingers. One is the first report of acral metástasis of a myoepithelial carcinoma of the breast. The other concerns acral metástasis as the first sign of lung carcinoma.

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%.

Cutaneous myoepithelial carcinoma with disseminated metastases.

Primary cutaneous neoplasms of myoepithelial differentiation are uncommon. Cutaneous myoepithelial carcinomas are rare. We report a case of cutaneous myoepithelial carcinoma in a 47-year-old man with a history of end-stage renal disease and renal transplant 19 years prior who presented to the hospital with a 3-month history of diffuse bone pain and an ulcerated scalp mass with multiple satellite lesions. This case illustrates a rare instance of metastatic disease from primary cutaneous myoepithelial carcinoma.

Locally Advanced Malignant Myoepithelioma of the Parotid Gland Treated With Radiotherapy: A Case Study and Review of the BC Cancer Agency Experience.

OBJECTIVES: Malignant myoepithelioma of salivary glands is a rare neoplasm; most arise in the parotid gland and minor salivary glands of the palate. Surgery has been the mainstay of treatment. METHODS: This is case report of a patient treated with primary radical radiotherapy and retrospective review of institutional experience. RESULTS: An 87-year-old man with locoregionally advanced malignant myoepithelioma of the parotid gland received radiotherapy alone with complete clinical response and sustained 39 months of posttreatment. Between 1981 and 2012, 15 cases of malignant myoepithelioma of the parotid were seen. Thirteen patients received surgical excision and adjuvant radiotherapy. At a median follow-up of 47 months, 12 patients were alive without recurrence, 2 died without recurrence, and 1 died with metastatic myoepithelioma. CONCLUSIONS: Durable locoregional disease control and disease-free-survival was achieved in the majority of patients. The case reported suggests radiation therapy may be an effective treatment option for inoperable cases.

A phase II study of sorafenib in recurrent and/or metastatic salivary gland carcinomas: Translational analyses and clinical impact.

BACKGROUND: Pre-clinical and clinical evidence suggests a rationale for the use of anti-angiogenic agents, including sorafenib, in recurrent and/or metastatic salivary gland carcinomas (RMSGCs). This study evaluates the activity of sorafenib in patients with RMSGCs and also investigates whether the activity of sorafenib could be related to its main tailored targets (i.e. BRAF, vascular endothelial growth factor receptor 2 [VEGFR2], platelet-derived growth factor receptor α [PDGFRα] and ß, RET, KIT). PATIENTS AND METHODS: Patients received sorafenib at 400 mg BID. The primary end-point was response rate (RR) including complete response or partial response (PR); secondary end-points included RR according to Choi criteria, disease control rate (DCR), overall survival (OS), and progression-free survival (PFS). RESULTS: Thirty-seven patients (19 adenoid cystic cancers, ACC) were enrolled. Six PRs were recorded. RR was 16% (95% confidence interval [CI]: 6-32; 11% in ACC and 22% in non-ACC). Choi criteria could be applied in 30 out of 37 cases with a RR of 50% (95% CI: 31-69%); DCR was 76% (95% CI: 59-88%). Incidence of ≥G3 adverse events was 29.7%. Median PFS and OS for the entire population were 5.9 months and 23.4 months, respectively. Median PFS and OS were 8.9 and 26.4 months for ACC versus 4.2 and 12.3 months for non-ACC patients. All the cases showed expression of PDGFRß in the stroma and VEGFR2 in endothelial cells; PDGFRα positivity was found in the stroma of four (27%) cases. All except for two cases showed no PDGFRß, VEGFR2 and PDGFRα expression in the tumour cells. KIT expression was restricted to ACC and a weak RET expression was limited to one adenocarcinoma, not otherwise specified (NOS). No BRAF mutation was found. No correlation was observed between the sorafenib activity and the expression of its markers although all six responders (two ACC, one adenocarcinoma, NOS, one salivary duct cancer [SDC], one high-grade mucoepidermoid [HG-MEC] and one poorly-differentiated cancer) are enriched in the stromal component showing a PDGFRß immunodecoration. In ACCs, immunohistochemistry revealed MYB protein expression in 15/16 cases (94%) and the MYB-NFIB fusion oncogene was observed in 9/14 (64%). CONCLUSIONS: Sorafenib is the first anti-angiogenic agent to demonstrate activity in RMSGC patients, particularly in some histotypes such as HG-MEC, SDC and adenocarcinoma, NOS. The PDGFRß-positive rich stromal component characterising these histotypes and the lack of correlation between the activity of sorafenib and its targets suggests anti-angiogenic effect as the prevalent mechanism of action of sorafenib in SGCs.

Epithelial-myoepithelial carcinoma metastasis to the thoracic spine.

Epithelial-myoepithelial carcinoma (EMC) is a very rare salivary gland malignancy accounting for less than 1% of salivary gland tumors, and classically arises from the parotid gland in females. Spinal cord compression caused by EMC metastasized from the parotid gland has only been described once in the literature to our knowledge. We report the first case of a patient with parotid EMC spinal metastasis undergoing a gross total resection with instrumented fusion. This case illustrates that an en bloc resection with a planned transgression through the spinal canal may be a reasonable option for EMC metastasized to the spine.

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.

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.

EWSR1 genetic rearrangements in salivary gland tumors: a specific and very common feature of hyalinizing clear cell carcinoma.

The Ewing sarcoma breakpoint region 1 (EWSR1) is translocated in many sarcomas. Recently, its rearrangement has been described in salivary gland hyalinizing clear cell carcinomas (HCCCs) and in a subset of soft tissue myoepitheliomas. This study examines the presence of the EWSR1 rearrangement in a variety of salivary gland lesions including classic myoepitheliomas and HCCCs. Using a tissue microarray and whole-mount sections, fluorescence in situ hybridization (FISH) was performed on a variety of salivary gland lesions including HCCCs. The EWSR1 rearrangement was detected in 87% of HCCCs (13 of 15); all other salivary gland lesions including classic myoepitheliomas had intact EWSR1. Patients with HCCCs with rearranged EWSR1 included 1 man, 10 women, and 2 of unknown sex. Ages ranged from 35 to 83 years; the tumor size ranged from 0.8 to 5.5 cm, and the involved locations included: palate (2), base of the tongue (2), mandible (2), submandibular gland (2), lip (1), floor of the mouth (1), sublingual gland (1), inner cheek (1), and nasopharynx (1). All HCCCs were composed of sheets and nests of monotonous cells with clear cytoplasm within a hyalinized stroma. All tested cases were immunoreactive with antibodies to p63 and were nonreactive with antibodies to more conventional myoepithelial antigens (e.g., smooth muscle actin and S100 protein). These findings show that the EWSR1 rearrangement is almost a defining feature of HCCCs and also confirm that classic salivary gland myoepitheliomas are distinct from these tumors and do not share a pathogenetic relationship with their soft tissue counterparts.

Metastasis of soft-tissue myoepithelial carcinoma to clivus.

The differential diagnosis for masses involving the clivus is broad. The authors present a case of myoepithelial carcinoma metastatic to the clivus, a lesion that has not been reported to their knowledge. This 14-year-old girl with a history of myoepithelial carcinoma originating in the soft tissues of the left hip and metastatic to the lung presented with left lateral gaze palsy. Imaging demonstrated a 3 × 3-cm osteolytic mass in the clivus. Microscopic transsphenoidal resection with endoscopic assistance was performed. Pathological findings were consistent with the previously diagnosed myoepithelial carcinoma. Within 4 weeks postoperatively and 2 weeks into a chemotherapeutic regimen, the tumor exhibited progression. Radiation therapy was started and growth of the tumor was halted. Myoepithelial carcinoma should be included in the differential diagnosis for clival masses, especially in patients with previously diagnosed myoepithelial carcinoma. The primary management of this tumor should be with chemotherapy and radiation, with surgery serving only for decompression.

[Epithelial-myoepithelial carcinoma of parotid gland: a tumor of low grade malignancy?]. / Carcinoma epitelial-mioepitelial da parótida: um tumor de baixo grau de malignidade?

Epithelial-myoepithelial carcinoma (EMC) is a rare tumor with predilection for the major salivary glands, mainly the parotid gland. It is a tumor of low grade malignancy, and despite its tendency to local recurrence with low metastatic potential, rare cases of EMC may have an aggressive behavior with distant metastasis. Treatment consists primarily of complete surgical resection whenever possible followed by radiotherapy (RT) in an attempt to prevent local recurrence. The authors describe two cases of patients with EMC from the parotid gland. Despite treatment and good local response both later developed pulmonary metastases, and also later cerebral metastization. In the sequence of these clinical cases, a literature review is made.

Dedifferentiated epithelial-myoepithelial carcinoma of the parotid gland with aberrant expression of prostate specific antigen: a case report.

This report describes a rare case of dedifferentiated epithelial-myoepithelial carcinoma (EMCa) of the parotid gland. The tumor had 2 distinct components; a well-differentiated EMCa comprising of ductal and myoepithelial cells with low nuclear grade and low proliferation index. The second component showed a completely different morphology comprising of sheets and clusters of poorly differentiated cells with high nuclear grade and proliferative activity. The dedifferentiation was associated with an accelerated clinical course. Dedifferentiated EMCa is extremely rare with only 8 cases reported in the English literature. An unusual feature, hitherto not described in this tumor is the aberrant expression of prostate-specific antigen in the dedifferentiated component. In male patients, this may cause diagnostic confusion with metastatic prostate carcinoma.

Heterogeneous genetic profiles in soft tissue myoepitheliomas.

Myoepithelioma, mixed tumor and parachordoma are uncommon soft tissue tumors thought to represent morphological variants of a single tumor type. The genetic basis of these neoplasms is poorly understood. However, they morphologically resemble mixed tumor of the salivary glands (also known as pleomorphic adenoma), a tumor characterized by deregulated expression of PLAG1 or HMGA2. To evaluate a possible genetic relationship between these soft tissue and salivary gland tumors, PLAG1 expression levels and the genomic status of PLAG1 and HMGA2 were investigated in five soft tissue myoepitheliomas and one pleomorphic adenoma. In addition, all tumors were cytogenetically investigated and whole genome DNA copy number imbalances were studied in five of them. The genetic profiles were heterogeneous and the only aberration common to all soft tissue myoepitheliomas was a minimally deleted region of 3.55 Mb in chromosome band 19p13. Recurrent deletion of CDKN2A suggests that inactivation of this tumor suppressor gene is pathogenetically important in a subset. Furthermore, PLAG1 rearrangement was found in a soft tissue tumor from a patient previously treated for a salivary pleomorphic adenoma, indicating either metastasis of the salivary gland lesion or that some soft tissue tumors develop through the same mechanisms as their salivary gland counterparts.