Myoepithelial Carcinoma ex Pleomorphic Adenoma: Rare Case Report with Clinicopathologic and Immunohistochemical Features

Introduction/Objective Myoepithelial carcinoma is identified by nearly exclusive myoepithelial differentiation and evidence of malignancy. It may arise de novo or in preexisting benign tumors including pleomorphic adenoma and benign myoepithelioma. It occurs most commonly in the parotid gland followed by submandibular glands, minor salivary glands, and occasionally in the sublingual gland. Nasopharyngeal origin has been rarely reported. Methods/Case Report An afebrile 19-year-old female presented to the emergency department with persistent facial pressure, otalgia (right side greater than left side), rhinorrhea, and several episodes of epistaxis. One month before, she has been treated with Amoxicillin for three days with no relief, where Augmentin started for her for five days. About four days prior presentation, she was placed on Prednisone and Cefdinir. Over the next several days, she began having throat pain with difficulty swallowing. Routine blood work revealed a leukocytosis of 14.2 with normal differentiation. CT of the neck showed a large soft tissue mass centered at the right nasopharynx. Flexible nasal endoscopy performed bilaterally to reveal the nasopharynx is entirely obstructed with a lobulated mass filling the nasopharynx. On the right side, it extends into the posterior nasal passage filling the sphenoethmoid recess and the posterior floor of the nasal passage. Outpatient biopsy from nasopharynx mass is also performed. Results (if a Case Study enter NA) Mass biopsy reveals a mucinous and chondromyxoid background with mixed epithelial and myoepithelial differentiation. The is squamous metaplasia of myoepithelial cells and prominent mitotic activity and apoptotic activity. Immunohistochemistry was positive for CK5/6, calponin, BCL2, SMA, BerEp4, Sox10, and a proliferative index up to 40%. Based on this information Myoepithelial Carcinoma ex-pleomorphic adenoma of the nasopharynx is the diagnosis. Conclusion Carcinoma ex pleomorphic adenoma is usually a high-grade malignancy. It occurs most commonly in the parotid gland, followed by submandibular glands, minor salivary glands, and occasionally in the sublingual gland. Our case is one of the few cases of myoepithelial carcinoma arising in nasopharyngeal pleomorphic adenoma.

Obstructing Trachea Tumor: Myoepithelial Carcinoma about a Case

Myoepithelial carcinoma, also called malignant myoepithelioma, is an extremely rare tumor of the salivary gland type. It is defined as a malignant neoplasm in which the tumor cells exhibit exclusively myoepithelial differentiation. Our case is a 48-year-old patient with no specific history who was presented to the hospital emergency room for respiratory difficulty and dysphagia progressively evolving for 08 weeks. A cervical CT was done which revealed a hypodense tumor process in T1 of 4 cm long axis obstructing the trachea well limited and richly vascularized. The diagnosis of tracheal myoepithelial carcinoma was made after histological and immunohistochemical analysis on a biopsy pending analysis of the operative specimen. Treatment remains initially surgical with appropriate postoperative radiotherapy and chemotherapy.

The Transcriptional Co-Activator Taz Contributes to the Differentiation of a Salivary Gland Epithelial Cell Line Towards a Myoepithelial Phenotype

Myoepithelial cells serve as contractile units in exocrine glands, including mammary, salivary, and lacrimal glands, and their dysfunction negatively impacts secretory function. In spite of their importance, mechanisms that regulate myoepithelial differentiation are poorly defined. To study this process, we employed an established murine salivary gland epithelial cell line, mSG-PAC-1, that we previously demonstrated recapitulates aspects of acinar cell differentiation when cultured as spheroids. Here, we report that mSG-PAC1 spheroids can be induced towards a myoepithelial phenotype by manipulating culture conditions, resulting in the inhibition of expression of the acinar marker, AQP5, the upregulation of myoepithelial markers alpha-SMA, calponin, and the integrin beta4 subunit, as well as the acquisition of myoepithelial morphology. Transcriptome analysis indicated that YAP/TAZ target genes are also upregulated. We demonstrate that the transcriptional co-activator TAZ is expressed by the same cells that express alpha-SMA in the epithelial compartment of the differentiating murine salivary gland and by mSG-PAC1 cells under conditions that promote a myoepithelial phenotype. Furthermore, siRNA targeting TAZ expression in mSG-PAC1 spheroids diminishes expression of myoepithelial markers, implicating TAZ in their regulation. Thus, we have demonstrated mSG-PAC1 cells are a reliable tool to complement in vivo approaches to understand mechanisms that promote myoepithelial differentiation.

Exploration of High-Grade Transformation and Postoperative Radiotherapy on Prognostic Analysis for Primary Adenoid Cystic Carcinoma of the Head and Neck

BackgroundDespite Adenoid cystic carcinoma (ACC) with cribriform or tubular components being recognized as a potentially indolent malignancy, ACC displaying solid or, more rarely, high-grade transformation (HGT) components is considered a more aggressive variant of the disease. As it is difficult to measure the proportion of the solid component objectively, and the role of HGT in the current grading system remains unclear, the prognostic influence of tumor grading remains controversial. In addition, postoperative radiotherapy (PORT) has been proven to be effective in local control of ACC of the head and neck (ACCHN) with a high rate of nerve invasion and close surgical margin. However it remains to be explored that whether PORT could improve the survival of patients with ACC, particularly those with HGT.MethodsA series of 73 surgically treated primary ACCHN cases were retrospectively accessed. Immunohistochemical staining was performed to observe the biphasic ductal-myoepithelial differentiation and to identify the HGT components of ACC for tumor grading. The correlation between tumor grading and clinicopathological characteristics was analyzed. Univariate and multivariate prognostic analysis were performed for progression-free survival (PFS) and overall survival (OS).ResultsOf the 73 included cases, 47 were grade I-II ACC and 26 were grade III ACC. Among the grade III cases, 14 with loss of biphasic ductal-myoepithelial differentiation identified by immunostaining were classified as HGT, and could be distinguished from conventional grade III cases. These HGT cases were correlated with a high propensity of lymph node metastases and more advanced stage. Univariate analysis demonstrated that tumor grading, perineural invasion, T stage, stage groups, and PORT were predictors for PFS, whereas tumor grading, margin status, and PORT were predictors for OS. However, only tumor grading and PORT were independent predictors for PFS and OS. The patients with HGT had significantly worse prognosis than those with conventional ACC. Moreover, disease progression tended to occur more frequently in younger patients. Among the patients with HGT, those who received PORT had a longer median survival time than those who did not.ConclusionHGT ACC identified by loss of biphasic differentiation should be considered in tumor grading. Tumor grading and PORT were independent predictors for disease progression and OS in surgically treated ACCHN patients.

FOXO1 gene involvement in a non-rhabdomyosarcomatous neoplasm

Myoepithelial neoplasms of soft tissue are rare tumors with clinical, morphological, immunohistochemical, and genetic heterogeneity. The morphological spectrum of these tumors is broad, and the diagnosis often requires immunostaining to confirm myoepithelial differentiation. Rarely, tumors show a morphology that is typical for myoepithelial neoplasms, while the immunophenotype fails to confirm myoepithelial differentiation. For such lesions, the term “myoepithelioma-like” tumor was introduced. Recently, two cases of myoepithelioma-like tumors of the hands and one case of the foot were described with previously never reported OGT-FOXO gene fusions. Here, we report a 50-year-old woman, with a myoepithelial-like tumor localized in the soft tissue of the forearm and carrying a OGT-FOXO1 fusion gene. Our findings extend the spectrum of mesenchymal tumors involving members of the FOXO family of transcription factors and point to the existence of a family of soft tissue tumors that carry the gene fusion of the OGT-FOXO family.