Epithelial-myoepithelial carcinomas of the bronchus

Pulmonary Epithelial-Myoepithelial Carcinoma

Pulmonary epithelial-myoepithelial carcinoma (P-EMC) is an exceptionally rare subtype of salivary gland lung tumor originating from tracheobronchial glands. P-EMC is a biphasic tumor consisting of an inner layer of epithelial cells and an outer layer of spindle-shaped, clear-cell-like myoepithelial cells. Bronchial obstruction symptom is the main clinical characteristic for P-EMC. Because its clinical and imaging characteristics are highly similar to other types of non-small-cell lung cancer (NSCLC), it is easy to cause missed diagnosis and misdiagnosis. The diagnosis is mainly based on the pathology and immunohistochemistry with an inner layer of epithelial cells immunoreactive for cytokeratin and an outside layer of myoepithelial cells immunoreactive for S100 protein (S-100) and smooth muscle actin (SMA). Therefore, positive for cytokeratin, S-100 and SMA can assist in the diagnosis. Although in general, P-EMC is a low-grade malignant neoplasm, it may occasionally recur and metastasize. The optimal method for P-EMC treatment has not been established, and surgical resection is still the main clinical method. Radiotherapy and chemotherapy have been shown not sensitive for P-EMC treatment, whereas targeted therapy and immunotherapy have not evaluated in clinical practice. This review focuses on the pathological characteristics, molecular characteristics, diagnosis, treatment, and prognosis of P-EMC.

Pulmonary epithelial-myoepithelial carcinoma (P-EMC) with focal high grade transformation: Molecular and cytologic findings

BACKGROUND

Pulmonary epithelial-myoepithelial carcinoma (P-EMC) is a rare type of salivary gland tumor of the lung. Diagnosis from preoperative biopsies or fine needle aspiration (FNA) cytology specimens is difficult given the rarity of the tumor and overlapping cytomorphology with other entities. These tumors generally have a good prognosis, however prior reports of recurrence and metastasis to lymph nodes have been reported. Further, little is known about the malignant potential of high grade transformation. The molecular characteristics of this entity are unknown, with only a few case reports commenting on molecular findings. Here, we report a case of P-EMC with focal high grade transformation. We present its diagnostic pitfalls on cytology specimens, surgical pathology, immunohistochemistry, and molecular findings.

CASE PRESENTATION

A 72 year old female presented with an incidentally detected lung mass. A chest computed tomography (CT) demonstrated a left hilar mass measuring 4.1 cm with endobronchial extension into the left upper lobe. On the initial endobronchial core needle biopsy and cytology FNA, the tumor was misinterpreted as squamous cell carcinoma. The patient subsequently underwent a left pneumonectomy along with mediastinal lymph node dissection. Final surgical pathology of the resection specimen indicated a P-EMC with focal high grade transformation. The patient is disease-free 1 year post-surgery.

CONCLUSIONS

Due to the rarity of P-EMC, insufficient sampling and histologic heterogeneity, diagnosis of P-EMC on preoperative core needle biopsy or FNA specimen is difficult. Herein, we present a rare case of P-EMC, with a pre-operative FNA cytology specimen that consisted of tumor cells with dense cytoplasm and moderate cytologic atypia, strong positive staining pattern of p40, that was misdiagnosed as squamous cell carcinoma. Follow up surgical resection showed P-EMC with focal high grade transformation. Salivary gland EMCs with high grade transformation have previously been reported to have a worse prognosis, however, little is known about the malignant potential in the lung. Next generation sequencing (NGS) using a 397-gene solid tumor panel identified variants in DNMT3A, APC, STAT3 in both low and high grade components, while KDM5C was present only in the high grade transformation.

[A Rare Case of Pulmonary Epithelial-myoepithelial Carcinoma: Case Report and Literature Review]

背景与目的

肺上皮-肌上皮癌（pulmonary epithelial-myoepithelial carcinoma, P-EMC）是一种十分罕见的涎腺型肺肿瘤，尚无标准治疗方案，本文拟分析肺上皮-肌上皮癌的临床特点，探讨肺上皮-肌上皮癌的诊疗方案。

方法

分析1例肺上皮-肌上皮癌患者的临床资料并回顾其他相关临床文献。

结果

上皮细胞免疫组化表达细胞角蛋白，肌上皮细胞免疫组化表达SMA及S-100，二代基因测序以HRAS基因突变为主，PD-L1蛋白为阴性。

结论

肺上皮-肌上皮癌大多预后良好，诊断以镜检及免疫组化为主，治疗以手术切除为主，放化疗效果尚不明确。

Diagnostic Significance of HRAS Mutations in Epithelial-Myoepithelial Carcinomas Exhibiting a Broad Histopathologic Spectrum

Epithelial-myoepithelial carcinoma (EMC) is a rare salivary gland tumor that is histologically characterized by biphasic tubular structures composed of inner ductal and outer clear myoepithelial cells. Because of its histologic variety, it is sometimes challenging to make an accurate diagnosis, and useful ancillary tests are essential for this purpose. We investigated 87 cases of EMC arising in the major and minor salivary glands and seromucinous glands in the nasal cavity or bronchus to describe the histologic features and mutation status of selected key oncogenes. Classic EMC accounted for 40.2% of all cases. Other cases showed various growth patterns and cytologic features in addition to the typical histology; cribriform patterns, a basaloid appearance, and sebaceous differentiation were relatively common (17.2% to 18.4%), whereas oncocytic/apocrine, papillary-cystic, double-clear, squamous, psammomatous, Verocay-like, and high-grade transformation were rare. HRAS mutations were found in 82.7% of EMCs and were concentrated in codon 61. There was no significant correlation between the HRAS mutation status and the histology. No EMC ex pleomorphic adenoma cases had HRAS mutations. PIK3CA and/or AKT1 mutations were the second most frequent mutations (20.7%, 6.5%, respectively) and almost always cooccurred with HRAS mutations. It is noteworthy that the HRAS mutation was not identified in any salivary gland tumor entities manifesting EMC-like features, including adenoid cystic carcinoma, pleomorphic adenoma, basal cell adenoma/adenocarcinoma, and myoepithelial carcinoma. We conclude that HRAS mutations are a frequent tumorigenic gene alteration in EMC, despite its histologic diversity. This study provides further insight into strategies for diagnosing EMC and discriminating it from its mimics.

Prognostic factors for survival after bronchoscopic intervention in patients with airway obstruction due to primary pulmonary malignancy

BACKGROUND

Malignant central airway obstruction (MCAO) occurs in 20-30% of patients with primary pulmonary malignancy. Although bronchoscopic intervention is widely performed to treat MCAO, little data exist on the prognosis of interventional bronchoscopy. Therefore, we evaluated the clinical outcomes and prognostic factors of bronchoscopic interventions in patients with MCAO due to primary pulmonary malignancy.

METHODS

This retrospective study was conducted at a university hospital and included 224 patients who received interventional bronchoscopy from 2004 to 2017, excluding patients with salivary gland-type tumor. A multivariable Cox proportional hazard regression analysis was used to identify independent prognostic factors associated with survival after the first bronchoscopic intervention.

RESULTS

Among 224 patients, 191 (85.3%) were males, and the median age was 63 years. The most common histological type of malignancy was squamous cell carcinoma (71.0%). Technical success was achieved in 93.7% of patients. Acute complications and procedure-related death occurred in 15.6 and 1.3% of patients, respectively. The median survival time was 7.0 months, and survival rates at one year and two years were 39.7 and 28.3%, respectively. Poor survival was associated with underlying chronic pulmonary disease, poor performance status, extended lesion, extrinsic or mixed lesion, and MCAO due to disease progression and not receiving adjuvant treatment after bronchoscopic intervention.

CONCLUSIONS

Interventional bronchoscopy could be a safe and effective procedure for patients who have MCAO due to primary pulmonary malignancy. In addition, we found several prognostic factors for poor survival after intervention, which will help clinicians determine the best candidates for bronchoscopic intervention.

Fine-needle aspiration cytology of the apocrine variant of epithelial-myoepithelial carcinoma

Epithelial‐myoepithelial carcinoma (EMCa) is a rare neoplasm that most frequently afflicts the parotid gland. Histologically, a dual layer of inner, luminal epithelial cells and outer myoepithelial cells with associated background hyalinization characterize these tumors. Several variants of EMCa have been described, including the more recent description of the apocrine variant. We present here a case of a 71‐year‐old male with a parotid mass diagnosed on FNA as an apocrine epithelial‐myoepithelial carcinoma. To our knowledge, this is the first case report describing the cytomorphologic features of apocrine EMCa on FNA smears.

Epithelial-myoepithelial carcinoma of the lung: a case report

BACKGROUND

Pulmonary epithelial-myoepithelial carcinoma (P-EMC) is a rare subset of salivary gland-type tumors of the lung. Because of its rarity and unproven malignant potential, the optimal therapy for P-EMC has not been defined. Here, we report a typical case of P-EMC and a review of the literature to consider appropriate treatment.

CASE PRESENTATION

A 54-year-old woman presented with an abnormal lung shadow on a routine chest X-ray. A chest computed tomography (CT) scan verified an 18-mm endobronchial nodule on the middle lobe. We performed a bronchoscopic biopsy, and the patient was diagnosed with P-EMC. After confirming the absence of tumors in the salivary glands, she underwent a right middle lobectomy along with hilar and mediastinal lymph node dissections. Currently, the patient is doing well, without any sign of recurrence 3 years after surgery.

CONCLUSIONS

Although a majority of P-EMC cases, as in our case, behave indolently, several poor progression cases have been reported. For distinguishing the minor malignancy cases from others, histological findings such as myoepithelial anaplasia could be a predictive factor. Complete resection is needed to evaluate the whole tumor, because P-EMCs often show histological heterogeneity. Moreover, incomplete excision may be a poor prognostic factor. Although lobectomies as well as lymph node dissections, sleeve lobectomies, or pneumonectomies are routinely performed for complete resection, further investigation is required to establish the optimal treatment strategy.

Sinonasal epithelial-myoepithelial carcinoma: Report of a novel subsite and review of the literature

BACKGROUND

Epithelial-myoepithelial carcinoma (EMC) is a rare tumor of the major and minor salivary glands. Sinonasal EMC is extremely uncommon and hitherto not described within the frontal or ethmoid sinuses.

OBJECTIVE

To present a novel sinonasal subsite and review the literature regarding sinonasal EMC.

METHODS

A case of frontoethmoidal EMC was presented. A medical literature data base was queried from January 1, 1950, to August 8, 2017, for all reports of sinonasal EMC.

RESULTS

A 69-year-old man underwent combined open and endoscopic craniofacial resection of a right frontoethmoidal EMC, a previously undescribed primary location for this tumor. A comprehensive review of the literature revealed 13 additional cases of sinonasal EMC.

CONCLUSION

EMC is an uncommon neoplasm typically found in the major salivary glands; occurrence in the nose or paranasal sinuses is extremely rare. EMC often follows an indolent clinical course, although, in a minority of cases, particularly in large tumors with nuclear atypia, more aggressive behavior may be observed.

A rare case of primary peripheral epithelial myoepithelial carcinoma of lung: Case report and literature review

BACKGROUND

Primary salivary gland-type tumors of lung are rare. Epithelial-myoepithelial carcinoma (EMC) of the lung is a minor salivary gland-type tumor subtype.

METHODS

We report a very rare case of EMC located in the peripheral left lower lobe that was diagnosed in a 58-year-old man and this is the first study in which we summarize all the patients with primary peripheral lung EMC concerned with the clinical features. Informed consent was obtained from the patient.

RESULTS

Chest computed tomography displayed an anomalous soft tissue mass with slightly lobular borders in the peripheral segment of the left lower lobe and closed to the visceral pleura. The surgery was performed by using video-assisted thoracic surgery. Grossly, the tumor was solitary, well-circumscribed, and unencapsulated endobronchial lesion. A microscopic examination revealed that it was circumscribed, although the tumor borders may show single cells or clusters of cells proliferating away from the main tumor mass. The inner tubular layer showed epithelial cell characteristics, whereas the outer layer exhibited myoepithelial cell characteristics. Immunostaining for P40, P63, and cytokeratin 5/6 was positive. However, the anaplastic lymphoma kinase-V, thyroid transcription factor-1, synaptophysin, chromogranin A and napsin A were negative.

CONCLUSIONS

Literature review showed that most of patients with peripheral EMC were asymptomatic. Computed tomography and magnetic resonance imaging scans are able to indicate the presence of peripheral EMC. Pathological analysis is an effective method to clarify the diagnosis. Surgery is a regular treatment method. To facilitate the preoperative diagnosis and avoid the misdiagnosis of such a rare disease, more cases will need to be reported.

Primary Pulmonary Salivary Gland-type Tumors: A Review and Update

Pulmonary salivary gland-type tumors (SGT) comprise a very small proportion of primary lung neoplasms. The most common tumors among this group are mucoepidermoid carcinoma and adenoid cystic carcinoma. Contrary to the head and neck region, benign SGT such as pleomorphic adenomas are exceedingly rare in the pulmonary system. More recently, 2 additional SGT, namely hyalinizing clear cell carcinoma and salivary duct-like carcinoma were recognized as primary lung tumors expanding the spectrum of SGT that have been described to originate in the tracheobronchial system. Primary pulmonary SGT must be clinically excluded from metastatic salivary gland neoplasms as their morphology is indistinguishable from that of their salivary gland counterparts. Little is known about the clinical behavior and best treatment approach for these unusual tumors. In this review, we provide a comprehensive summary of primary pulmonary SGT with particular emphasis on morphologic characteristics and latest developments in terms of immunohistochemical and molecular techniques.

Myoepithelial carcinoma treatment in children: a report from the TREP project

BACKGROUND

Myoepithelial carcinoma (MC) of soft tissues is an aggressive tumor that rarely affects children, for whom no established treatment protocols exist. As part of the TREP (Tumori Rari in Età Pediatrica) project - an Italian network dedicated to children and adolescents with very rare tumors - we present a series of patients with MC, who were treated homogeneously and achieved a satisfactory outcome.

PROCEDURE

From 2005 to 2012, seven patients (age 0.5-9.2 years) with a diagnosis of MC were registered in the TREP study. After one patient treated with ifosfamide, cisplatin, and etoposide showed tumor shrinkage and experienced long-term disease remission, all subsequent patients were treated with the same chemotherapy regimen. All patients also received radiotherapy.

RESULTS

Initial surgical management involved a biopsy in three cases and tumor resection in 4. Response to initial chemotherapy was evaluable in four patients: two had a partial remission, one a minor response and one stable disease. Four patients received external-beam radiotherapy and three had brachytherapy. Overall, six patients are alive in first complete remission with a median follow-up of 2.5 years (0.9-5.1 years).

CONCLUSIONS

Though our experience is limited to a small number of patients, our treatment strategy for patients with MC is appears clinically useful and demonstrates how cooperation within the TREP project has enabled enough data to be collected to propose treatment recommendations for pediatric patients with this very rare tumor.

Oncocytic and apocrine epithelial myoepithelial carcinoma: novel variants of a challenging tumor

Epithelial myoepithelial carcinoma (EMCa) is a rare but well characterized biphasic salivary gland malignancy with several variant morphologies. Oncocytic and apocrine EMCa are uncommon variants that constitute up to 8 % of all EMCa. Both variants invoke an eosinophilic or oncocytic differential diagnosis and challenge the traditional requirement of clear myoepithelial cells for EMCa. Oncocytic EMCa occurs in patients a decade older than conventional EMCa. This variant is often papillary with calcification and associated with sebaceous components and occurs in older individuals. Apocrine EMCa is named for its apocrine ductal component, which may be mistaken for salivary duct carcinoma. In this variant, the epithelial component often shows overgrowth in a cribriform or even solid pattern and is immunophenotypically defined by androgen receptor and gross cystic disease fluid protein 15 positivity. The most important aspect of differentiating both oncocytic and apocrine EMCa from other salivary oncocytic tumors is recognition of the biphasic nature of these variants and confirmation that the abluminal outer layer consists of plump, 'activated' myoepithelial cells, regardless of tinctorial characteristics. Both oncocytic and apocrine EMCa behave very indolently in the limited literature to date.

Primary epithelial myoepithelial carcinoma of lung, reporting of a rare entity, its molecular histogenesis and review of the literature

Primary epithelial myoepithelial carcinoma of lung is a rare entity and is thought to arise from the submucosal bronchial glands distributed throughout the lower respiratory tract. Because of the rarity of this tumor, we describe one case of epithelial myoepithelial carcinoma arising in the bronchus intermedius and presenting as an endobronchial mass. A 57-year-old male patient presented with an incidental finding of an endobronchial mass located in the lumen of the right lower lobe bronchus and caused near total luminal occlusion of the bronchus. An endobronchial carcinoid tumor was entertained clinically. Subsequently the patient underwent an uneventful videothoracoscopic lobectomy of lower and middle lobes of the right lung. Morphologically and immunohistochemically the tumor was characterized by two cell populations with epithelial and myoepithelial cells forming duct-like structure. The final diagnosis of epithelial myoepithelial carcinoma of lung was rendered.

Epithelial-myoepithelial tumour of the lung: a case report referring to its molecular histogenesis

Tracheobronchial submucous glands can be considered the pulmonary equivalent of minor salivary glands and therefore they can develop most of the tumours originated in these. Nevertheless, in spite of the wide distribution of this kind of glands along the tracheobronchial tree, pulmonary salivary gland-like neoplasms are not very frequent. Among them, the most frequent are mucoepidermoid and adenoid cystic carcinomas. On the contrary, pulmonary neoplasms showing a mixture of epithelial and myoepithelial elements are extraordinary infrequent, with only 11 cases collected from literature.

We present the case of a 76 year-old woman with no interesting pathological history, to whom a pulmonary nodule is detected during a study of unknown origin neutropenia. An upper right lobectomy is performed.

After macro and microscopic study, the diagnosis of pulmonary epithelial-myoepithelial tumour is made. It is a low malignant potential tumour with capacity to locally recur and less frequently to metastasize. Our case has the peculiarity of not being connected neither to visceral pleura nor to bronchial tree; we have not found this characteristic in any literature reviewed case.

These tumours have been named in a lot of different ways, including adenomyoepithelioma, epithelial-myoepithelial tumour, epithelial-myoepithelial carcinoma or epithelial-myoepithelial tumour of uncertain malignant potential.

The p27/kip-1 protein plays a fundamental role in the development of these neoplasms. As we have verified in our case, its aberrant cytoplasmic location, besides its proved oncogenic function, would favour the proliferation of stem cells, which would explain both dual phenotype with presence of myoepithelial cells without connection with the bronchial tree, and TTF-1 immunostaining in epithelial cells.

Skull metastasis as initial manifestation of pulmonary epithelial-myoepithelial carcinoma: a case report of an unusual case

Epithelial-myoepithelial carcinoma (EMC) of the lung is rare and is considered to be low-grade malignancy. Intracranial metastasis of pulmonary EMC has not previously been reported according to our search of the literature. We report a case of skull metastasis as the initial manifestation of pulmonary EMC. An 81-year-old man complained of left leg motor weakness. Neurological examination showed left hemiparesis. Computed tomography and magnetic resonance imaging revealed an osteolytic tumor in the right frontal bone with invasion to the dura and subdural space, attached to the superior sagittal sinus. Subtotal removal of the tumor was performed, and the left hemiparesis showed improvement. Histopathological study revealed the tumor to consist of epithelial and myoepithelial cells. Pulmonary EMC was diagnosed. The MIB-1 index in primary lesion was approximately 10%. The skull and dura are possible sites for metastasis from pulmonary EMC. The MIB-1 index is a predictive marker of malignant potential.

Primary myoepithelial carcinoma of the lung: a rare entity treated with parenchymal sparing resection

Primary lung myoepithelial carcinomas are rare neoplasms arising from the salivary glands of the respiratory epithelium. Given the rare occurrences and reports of these tumors, appropriate recommendations for resection are difficult to formulate. Although classified as low-grade neoplasms, these tumors have a significant rate of recurrence and distant metastasis.

Primary adenomyoepithelioma of tonsil

We present a case of adenomyoepithlioma (AME) arising from the tonsil. AME is an uncommon tumor that typically arises in breast, but rarely found in salivary glands, lung, and skin. Its biological features have not been thoroughly characterized. Here we describe a primary AME originating from the tonsil. The pathologic changes were characterized by hypercellularity, the dominance of both epithelial and myoepithelial cells. Malignancy was evidenced by the presence of a high mitotic rate and invasive growth. The epithelial cells express high levels of cytokeratin and epithelial membrane antigen (EMA). The myoepithelial cells show positive staining for calponin, p63, vimentin, and S-100. A thorough review of the literature indicates that this is likely the first reported case of AME from the tonsil. Following descriptions of the diagnosis, treatment, and prognosis of this specific case, pathologic and clinical characteristics of AME from other tissues are also compiled and discussed.

Epithelial-myoepithelial carcinoma of the lung: a case report and review of the literature

Epithelial-myoepithelial carcinoma is a rare carcinoma, most frequently seen in the salivary gland. There are no case reports in the pediatric population of isolated lung lesions. In this case report, we describe a 7-year-old patient with isolated lung epithelial-myoepithelial carcinoma and the management of such a lesion.

Recurrent Bronchial Epithelial-Myoepithelial Carcinoma After Local Therapy

We present a rare case of recurrent multiple lesions of bronchial epithelial-myoepithelial carcinoma in a 74-year-old man treated with local resection. Two cellular types were found: epithelial cells and myoepithelial cells. The patient remains asymptomatic at 4-years of follow-up, supporting the fact that epithelial-myoepithelial carcinoma is a tumor of low-grade malignancy.

Pneumocytic Adenomyoepithelioma: A Distinctive Lung Tumor With Epithelial, Myoepithelial, and Pneumocytic Differentiation

Pulmonary tumors with epithelial and myoepithelial differentiation are rare, thought to be of bronchial minor salivary gland origin and classified similarly to salivary gland neoplasms. We report a series of a distinctive subtype of pulmonary glandular tumors showing epithelial and myoepithelial differentiation with further pneumocytic specialization. All patients were women, aged 52 to 63 years and presented with single or multiple pulmonary nodules. The tumors were grossly circumscribed, 0.8 to 2.6 cm in greatest dimension, and histologically showed glandular and spindle cell differentiation. Some glands were filled with colloidlike secretion and had an inner, cuboidal epithelial cell layer (pankeratin, epithelial membrane antigen, and thyroid transcription factor-1 positive), surrounded by an outer layer of myoepithelial cells merging with foci of spindled myoepithelial cells (high molecular weight keratin, S100, smooth muscle actin, calponin, caldesmon, and p63 positive). There were also some glands lined by a single layer of plump cells that were positive for surfactant protein-A in addition to the other epithelial cell markers. Electron microscopy confirmed pneumocytic features in these cells and the myoepithelial nature of the spindled cells. The surgery in all cases was wedge resection of the masses. The biologic behavior to date has been benign. This is the first reported series of a distinctive lung tumor with epithelial, myoepithelial, and pneumocytic differentiation that differs histologically from all previously recognized pulmonary salivary gland-type and pneumocytic tumors. It is a unique benign appearing neoplasm for which the designation pneumocytic adenomyoepithelioma is suggested.

Bronchial epithelial-myoepithelial carcinoma

An epithelial-myoepithelial tumor is an extremely rare pulmonary neoplasm. Only 21 cases have been reported to date. This report presents a case of left main bronchial epithelial-myoepithelial carcinoma in a 43-year-old woman. No mediastinal lymph nodes were enlarged in computed tomographic scan, and no tumor growth was noted beyond the bronchial cartilage layer by endobronchial ultrasound imaging. This report highlights the usefulness of endobronchial ultrasound imaging for determining the depth of tumor invasion and choosing an alternative approach to surgical resection.

Epithelial-myoepithelial carcinoma: a review of the clinicopathologic spectrum and immunophenotypic characteristics in 61 tumors of the salivary glands and upper aerodigestive tract

To further define the clinicopathologic spectrum of epithelial-myoepithelial carcinoma (EMCa), we report the gross, histologic, and immunophenotypic characteristics of 61 tumors seen within a 30-year-period. The mean age at presentation was 60.9 years, with a female predominance (1.5:1). The most common sites were parotid (62.1%), sinonasal mucoserous glands (10.3%), palate (8.6%), and submandibular (8.6%). Most EMCas showed a characteristic nodular/multinodular growth pattern and classic biphasic tubular histology. However, new morphologies in EMCa such as ancient change (8.2%), "Verocay"-like change (3.3%), and sebaceous differentiation (13.1%) were noted. Specific histologic variants were dedifferentiated EMCa (3.3%), oncocytic EMCa (8.2%), EMCa ex pleomorphic adenoma (1.6%), double-clear EMCa (3.3%), and EMCa with myoepithelial anaplasia (3.3%). All cytokeratin cocktails selectively highlighted the epithelial component well. Of the myoepithelial markers, p63, smooth muscle actin and vimentin performed best. Bcl-2 and c-kit were frequently positive (66.7% and 69.2%, respectively). p53 was highly expressed only in 1 dedifferentiated EMCa. The recurrence rate was 36.3% (median disease-free survival 11.34 y), but death was rare with 5-year and 10-year disease-specific survivals of 93.5% and 81.8%, respectively. The most important univariate predictors of recurrence were margin status (log rank P=0.006), angiolymphatic invasion (P=0.002), tumor necrosis (P=0.004), and myoepithelial anaplasia (P=0.038). Thus, EMCa is generally a low-grade tumor with a broader morphologic spectrum than previously thought, with several key features predictive of recurrence. Immunohistochemistry can aid diagnosis by highlighting the biphasic nature of the tumor.

Soft tissue myoepithelial carcinoma

Background. Myoepitheliomas are tumors composed predominantly or exclusively of myoepithelial cells, usually arising in salivary glands. Cutaneous/soft tissue localization is very rare, especially for the malignant myoepitheliomas. Case report. We presented a case of myoepithelial carcinoma involving subcutaneous adipose tissue of the left forearm in a woman aged 62 years. The tumor was composed of epithelioid and hyaline cell types, arranged in diffuse sheets, nests and loose clusters within hyalinized and myxoid matrix. The neoplasm displayed high-grade cytologic atypia with some cells having pleomorphic, hyperchromatic nuclei, and others showing vesicular nuclei, large nucleoli with scattered bizarre giant cells. High mean mitotic count of 7 mitoses/10 high power fields and extensive necrosis favored the diagnosis of malignancy. Immunohistochemical staining was positive for cytokeratin (AE1/AE3), epithelial membrane antigen, S-100 protein, glial fibrillary acidic protein, and vimentin. Conclusion. Considering the subcutaneous localization, myoepithelial immunophenotype and high-grade cytologic atypia the neoplasm was classified as a soft-tissue myoepithelial carcinoma.

Myoepitheliale Tumoren der Haut und des Weichgewebes

Myoepithelial neoplasms of skin and soft tissues comprise cutaneous mixed tumor (chondroid syringoma), mixed tumor of subcutaneous and deep soft tissues, myoepithelioma and rare malignant myoepithelioma (myoepithelial carcinoma). Myoepithelial tumors of skin and soft tissues are characterized by an extreme clinicopathological heterogeneity as in other anatomic locations. The neoplasms arise in childhood as well as in adults and are composed of epithelioid, histiocytoid, spindled, plasmocytoid and/or clear tumour cells in varying combinations, and are set in a myxoid or hyalinised intercellular matrix. Immunohistochemically, neoplastic cells stain positively for epithelial markers (pancytokeratin and/or epithelial membrane antigen), and often for S 100 protein. More rarely muscle actin, glial fibrillary acid protein, calponin, and p63 are expressed, whereas desmin is usually negative. The presence of at least moderate cytological atypia is associated with a significant risk for aggressive behavior and propensity for metastasis.

Origin and phenotype of lung side population cells

Side population (SP) cells, a rare cell type identified by their ability to efflux the vital dye Hoechst 33342, are highly enriched for stem cell activity. Bone marrow (BM) SP cells uniformly express the pan-hematopoietic marker CD45, whereas tissue SP cells are heterogeneous in CD45 expression. In previous studies, we found that CD45 is expressed on 75% of lung SP cells. By performing whole BM transplantations, we determined that CD45-positive and CD45-negative lung SP cells are marrow derived. Transplantation of 200 highly purified BM SP cells indicated that both lung SP cell subtypes are derived from this marrow cell type. Morphologically, CD45-positive lung and BM SP cells possess similar features. They are small, round, and contain scant cytoplasm. CD45-negative lung SP cells are larger and contain abundant granular cytoplasm. Gene expression patterns for hematopoietic transcription factors GATA-1, GATA-2, and PU.1 further differentiated SP marrow and lung subtypes. By immunostaining for α-smooth muscle actin and cytokeratin, we found significant differences in the relative expression patterns of these markers in lung and marrow SP cell subtypes. In summary, these findings demonstrate that lung SP cells are derived from the BM and that CD45-positive and -negative subtypes can be distinguished by morphological differences and gene expression patterns.

Bronchial Epithelial-Myoepithelial Carcinoma

Epithelial-myoepithelial tumor is extremely rare as a pulmonary neoplasm. Only 20 cases have been reported to date, of which 14 were malignant. We report a case of intrabronchial epithelial-myoepithelial carcinoma in a 73-year-old man with a history of heavy smoking. The tumor was well-circumscribed and caused distal airway obstruction. Histologically, the tumor showed glandular and solid architecture. The glands were composed of an inner layer of epithelial cells and an outer layer of myoepithelial cells. The solid areas consisted of spindle-shaped myoepithelial cells. Immunohistochemical staining was positive for p53 and c-Kit (CD117). Focal atypia and increased mitotic activity were present, but no vascular invasion or nodal metastasis was identified.

Cutaneous myoepithelial neoplasms: clinicopathologic and immunohistochemical study of 20 cases suggesting a continuous spectrum ranging from benign mixed tumor of the skin to cutaneous myoepithelioma and myoepithelial carcinoma

BACKGROUND

Myoepithelial neoplasms, both benign and malignant, are rare but well-established clinicopathologic entities in the salivary glands, the breast, and the lung. Despite similarities between cutaneous sweat glands and glandular structures in the above-mentioned organs as well as the presence of regular myoepithelial cells around cutaneous eccrine/apocrine glands, the concept of cutaneous myoepithelial neoplasms is still debatable and not commonly accepted.

METHODS

Twenty cutaneous myoepithelial neoplasms have been studied histologically and immunohistochemically.

RESULTS

Nine neoplasms showed features of benign mixed tumor of the skin (chondroid syringoma) (five females and four males, age range 19-65 years, all cases arose in the head and neck region). Two cases represented the eccrine and seven the apocrine subtype. Interestingly, in three cases of the apocrine subtype, solid areas composed predominantly of myoepithelial cells were detected; these neoplasms were designated as benign mixed tumors with prominent myoepithelial cells. Nine cutaneous neoplasms were composed of spindled, epithelioid, and plasmocytoid cells without ductal differentiation and immunohistochemically stained variably positive for vimentin, epithelial and myogenic markers, S-100 protein, calponin, and glial fibrillary acidic protein (four females and five males, age range 3-71 years, four cases arose in the head and neck region and one case each on the finger, the thigh, the lower leg, the foot, and the breast, respectively); these neoplasms were designated as cutaneous myoepitheliomas. Two morphologically malignant neoplasms with cytologic and immunohistochemical features of myoepithelial cells arose on the face of a 70-year-old female and a 79-year-old male patient; these neoplasms were designated as malignant cutaneous myoepitheliomas (cutaneous myoepithelial carcinomas).

CONCLUSIONS

The study suggests a continuous spectrum of cutaneous myoepithelial neoplasms ranging from benign mixed tumor of the skin to cutaneous myoepithelioma and cutaneous myoepithelial carcinoma. Further studies with extended follow-up information are necessary to establish prognostic factors.

Carcinosarcoma of the esophagus characterized by myoepithelial and ductal differentiations

We report a case of carcinosarcoma of the esophagus characterized by ductal and myoepithelial differentiation. A 61-year-old man was operated on for a polypoid tumor of the distal esophagus. Histologically, this tumor was composed of ductal structures and sarcomatous spindle cells surrounding the ducts at the central area of the tumor. The tumor was also composed of squamous cell and basaloid carcinoma in the periphery. Immunohistochemically, a few spindle cells surrounding the ductal structures showed immunopositivity for alpha-smooth muscle actin and S-100 protein. Electron microscopy revealed that the spindle cells had tonofilament and pinocytic vesicles in the cytoplasm, and basal lamina adjacent to the cytoplasmic membrane. Both of the results strongly supported the suggestion that the spindle cells may be myoepithelial cells. Basaloid carcinoma showed a gradual transition to chondrosarcomatous cells producing the matrix, which had both immunopositivities for S-100 protein and cytokeratin. Therefore, chondrosarcomatous cells may be derived from carcinoma cells. The histogenesis of this tumor may be associated with a totipotent stem cell of esophageal mucosa, which has the potential to differentiate into squamous cells, ductal cells or myoepithelial cells.