Anaplastic myoepithelial carcinoma of the sinonasal tract: an underrecognized salivary-type tumor among the sinonasal small round blue cell malignancies? Report of one case and a review of the literature

Imaging features of a myoepithelial carcinoma of the nasal cavity: A case report and literature review

Myoepithelial carcinoma of the nasal cavity is extremely rare. We report the case of a 66-year-old man with myoepithelial carcinoma of the nasal cavity. Computed tomography (CT) and magnetic resonance imaging revealed a lobulated soft tissue mass with central necrosis and hemorrhage, as well as an invasion of the skull base and left orbit. The patient presented with continuous nasal congestion and heavy head and had no elevated level of squamous cell carcinoma-related antigen. CT, magnetic resonance imaging, or ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/CT revealed no evidence of a metastatic lesion. ¹⁸F-FDG accumulation in the tumor was inhomogeneous and moderate. Histopathological examination of the resected specimen confirmed a well-circumscribed solid tumor with septa, a small area of hemorrhage, and necrosis. The subsequent diagnosis was a myoepithelial carcinoma of the left nasal cavity. This case shows that nasal myoepithelial carcinoma might appear as a well-defined lobulated mass with hemorrhagic necrosis and intense contrast enhancement in the solid component. We conjecture that hemorrhagic necrosis and intense enhancement values may be potential markers of nasal myoepithelial carcinoma.

A National Cancer Database Analysis of Sinonasal Malignant Myoepithelial Carcinoma Outcomes

OBJECTIVES

Myoepithelial carcinoma (MECA) is a rare salivary gland tumor that can occur in the sinonasal cavity with poor outcomes. There are limited data on sinonasal outcomes to guide management. We sought to use the National Cancer Database (NCDB) to better define treatment outcomes in MECA.

METHODS

We conducted a retrospective analysis of the NCDB from 2004 to 2016 for patients with MECA of the sinonasal cavity. Patient demographic, treatment, and survival information were extracted from the database. Unadjusted Kaplan-Meier estimates, log-rank tests, and a multivariable Cox proportional hazard model were used to assess overall survival (OS).

RESULTS

A total of 38 patients were included. The average age was 60.7 ± 18.2 years and male patients represented 47.4% of the cohort. Most patients were White (n = 26, 68.4%) and the majority of patients had either private insurance (n = 20, 52.6%) or Medicare (n = 15, 39.5%). The primary site of most tumors was nasal cavity (n = 19, 50%), followed by maxillary sinus (n = 16, 42.1%). Most tumors were >4 cm (n = 17, 44.7%). The 1-, 5-, and 10-year OS was 89.7% (95% confidence interval [CI]: 80.7%-99.8%), 63.6% (95% CI: 49.4%-82%), and 46.4% (95% CI: 31%-69.5%), respectively. The median survival for the overall cohort was 85.8 months. Medicare insurance was associated with a decreased OS (hazard ratio [HR]: 8.2; 95% CI: 2.88-23.4, P < .001). Patients who underwent surgery had a significant survival benefit (HR: 0.04, 95% CI: 0.01-0.21, P < .001).

DISCUSSION

MECA of the sinonasal cavity is a rare tumor with poorly understood behavior. Data from the NCDB suggests that it is a relatively aggressive tumor with surgical management associated with better outcomes. This analysis is limited by the small sample size and further research into optimal treatment regimens is needed.

Malignant Myoepithelioma of the Head and Neck: Demographics, Clinicopathological Characteristics, Treatment, and Prognosis

Malignant myoepithelioma of the head and neck (HNMM) is a rare malignancy, and its characteristics and survival rates have not been well-defined. This study aimed to define the epidemiology of HNMM and identify the prognostic factors associated with the disease. Data on all patients diagnosed with HNMM between 1991 and 2016 were gathered from the Surveillance Epidemiology and End Results (SEER) database. The demographics, clinicopathological characteristics, treatment, and prognoses of the patients were described. Cox regression analysis was used to identify the prognostic factors, and the prognostic nomograms for overall survival (OS) and disease-specific survival (DSS) were constructed. A total of 333 cases of HNMM were identified. The average age at diagnosis was 60.6 years, and 50.1% of the patients were men. After diagnosis, 46.2% of patients underwent surgery alone, 43.5% of patients underwent surgery and radiotherapy, and 3.6% of patients received only radiotherapy. Survival analysis showed that the 5-year OS and DSS for all HNMM patients were 69.7 and 82.1%, respectively. In the multivariate analysis model, the undifferentiated pathological grade (P <0.05) and M1 in the M category (P <0.01) were independent prognostic factors for poor OS and DSS, whereas the use of surgical resection was an independent favorable prognostic factor for both OS and DSS (P <0.05). The prognostic nomograms for OS and DSS prediction were constructed; the C-index values for OS and DSS prediction were 0.78 (95% CI 0.70–0.86) and 0.79 (95% CI 0.67–0.90), respectively. In conclusion, this SEER data-based study demonstrated that HNMM patients often had a favorable prognosis, and distant metastasis, pathological grade, and the use of surgery contributed to their survival. Furthermore, we developed a prognostic nomogram to predict OS and DSS for HNMM patients to aid physicians in the clinical management of this rare disease.

Pleomorphic adenoma of the left lacrimal gland recurred and transformed into myoepithelial carcinoma after multiple operations: A case report

BACKGROUND

Myoepithelial carcinoma (MC) is a clinically rare malignancy, there is controversy regarding its etiology and its biological behavior is not fully elucidated. Extensive surgical resection is the main treatment method. We describe a case of pleomorphic adenoma (PA) with multiple postoperative recurrences after malignant transformation, and the history of the disease in this patient was more than 20 years. Complete resection during the first surgery of PA and long-term postoperative follow-up is necessary.

CASE SUMMARY

A 34-year-old male with PA and a history of 5 postoperative recurrences over 21 years, each surgically removed, presented 15 d ago with headache, nasal congestion, protrusion of the right eyeball and loss of vision in the right eye, with progressively worsening symptoms. The patient underwent surgery, and MC was confirmed by pathology examination. A small PA component was locally visible under light microscope. The patient had a recurrence of the tumor 2 mo after surgery and underwent surgical resection.

CONCLUSION

During the first operation for PA, care should be taken not to rupture the envelope to prevent tumor cell implantation, and when complete resection is not possible due to the anatomical site, postoperative radiotherapy is necessary to control the lesion and prevent infiltration and malignant transformation of the tumor to MC. Computed tomography and magnetic resonance imaging is important for establishing diagnosis and developing a treatment plan.

Clear Cell Myoepithelial Carcinoma Arising from the Hard Palate with Metastasis to the Lungs

Myoepithelial carcinoma is an uncommon tumor of the salivary glands, most commonly the parotid gland. Clear cell myoepithelial carcinoma is a rare variant with an aggressive behavior. Here, we describe a case of clear cell myoepithelial carcinoma arising from the hard palate in an elderly male who underwent resection of the tumor and postop radiation. Posttreatment imaging demonstrated bilateral pulmonary nodules and a C2 body lesion concerning for metastasis. Biopsy of the lung lesions revealed a monomorphous population of optically clear cells with hyperchromatic and pleomorphic nuclei which were morphologically similar to the prior resection specimen. There are few reported cases of clear cell myoepithelial carcinoma arising from the hard palate, and there are even fewer reports on metastases to the lungs. Due to the low number of reported cases, prognosis and treatment of this neoplasm is not well defined.

High-grade myoepithelial carcinoma can show histologically undifferentiated/anaplastic features

High grade malignant tumors with a poorly-/un-differentiated morphology pose significant diagnostic challenges. Increasingly, the use of adjunct immunohistochemical and molecular tests to characterize and delineate the histopathologic phenotype of these tumors has become necessary, particularly in head and neck tumors. Recently, several entities with a poorly-/un-differentiated light microscopic morphology have been defined based on specific immunohistochemical and genetic characteristics. We herein describe two cases of high-grade myoepithelial carcinoma, one occurring in the submandibular gland and the other occurring in the left nasal cavity, both showing undifferentiated histological and anaplastic cytomorphological features. This led to very broad differential diagnostic considerations and the diagnosis was only established after extensive immunohistochemical studies. Molecular testing for HPV was negative in both cases. Gene fusion analysis using a targeted sequencing assay (Archer® FusionPlex® system) did not identify fusions involving PLAG1, HMGA2, EWSR1 or ALK genes in either case. The submandibular tumor showed an aggressive clinical course, with diffuse pulmonary metastases at presentation, whilst the nasal cavity tumor showed only localized disease. Awareness of a subcategory of high-grade myoepithelial carcinomas with undifferentiated light microscopical features is of significant importance in antibody selection for immunohistochemical investigation of poorly-/undifferentiated malignant tumors in the head and neck region. This histological variant of myoepithelial carcinoma adds to the growing list of differential diagnoses in this diagnostically complex and multifaceted field.

An Update on Sinonasal Round Cell Undifferentiated Tumors

The sinonasal cavities host a wide variety of undifferentiated malignancies with round cell morphology, including neoplasms of epithelial, mesenchymal, neuroectodermal, and hematolymphoid lineage. The differential diagnosis may be difficult, especially in small biopsy material, due to overlapping morphology, but their correct classification is clinically relevant. The aim of this review is to provide practical guidelines for the differential diagnosis of these malignancies, with emphasis on recently described entities and special reference to the role of ancillary techniques.

Nasal Cavity and Paranasal Sinuses

The nasal cavity and paranasal sinuses occupy the top of the upper respiratory tract and form pneumatic spaces connected with the atmosphere. They are located immediately beneath the base of the cranium, where crucial vital structures are harbored. From this region, very much exposed to airborne agents, arise some of the more complex and rare benign and malignant lesions seen in humans, whose difficulties in interpretation make this remarkable territory one of the most challenging in the practice of surgical pathology.

Contents of this chapter cover inflammations and infections, polyps and pseudotumors, fungal and midfacial destructive granulomatous lesions, as well as benign, borderline, and malignant neoplasms. Among the neoplasms, emphasis is made on those entities characteristic or even unique for the sinonasal region, such as Schneiderian papillomas, glomangiopericytoma, intestinal- and non-intestinal-type adenocarcinomas, olfactory neuroblastoma, nasal-type NK-/T-cell lymphoma, and teratocarcinosarcoma. Moreover, recently recognized entities involving this territory, i.e., HPV-related non-keratinizing carcinoma, NUT carcinoma, and SMARCB1-deficient basaloid carcinoma, are also discussed in the light of their specific molecular findings. Furthermore, the text is accompanied by numerous classical and recent references, several tables, and 100 illustrations.

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

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