Subcutaneous Myoepithelioma in the Extremity: A Potential Pitfall in the Differential Diagnosis of Subcutaneous Tumors.

We present a rare case of myoepithelioma in the subcutaneous layer of the shoulder with ultrasonography (US) and magnetic resonance imaging (MRI). US showed a lobulated hyperechoic mass, leading to an impression of lipoma. MRI showed the mass with low signal intensity on T1-weighted images (T1WI), high signal intensity on fat-suppressed T2-weighted images (T2WI), intermediate signal intensity on T2WI, and intense enhancement with adjacent fascial thickening. Imaging findings of soft tissue myoepithelioma have not been established. We report its US and MRI features mimicking features from a lipomatous tumor to infiltrative malignancy. Although soft tissue myoepithelioma has nonspecific image findings to confirm its diagnosis, some findings may help to make the differential diagnosis. Preoperative pathologic confirmation is recommended in a soft tissue neoplasm.

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.

Epithelial-Myoepithelial Carcinoma of the Submandibular Gland: Case Report.

Epithelial-myoepithelial carcinoma (EMC) is a rare malignant salivary gland tumor that occurs mostly in the parotid gland. We report a case of EMC of the submandibular gland in a young man. The patient was aware of a slow-growing mass in the right submandibular gland for 1 year. Clinical examination and ultrasound confirmed a right submandibular mass, 2.5 × 3 cm2 in size. Ultrasound-guided fine-needle aspiration indicated a diagnosis of pleomorphic adenoma, which was also suggested by magnetic resonance imaging. The submandibular gland tumor was excised. Immunohistochemical analysis showed carcinoma ex pleomorphic adenoma with a major epithelial-myoepithelial component. The patient was not treated with radiotherapy after surgery. No recurrence was observed during 24 months of follow-up. Because the morphology of EMC is similar to that of a benign tumor, it is frequently initially misdiagnosed. Surgery is always the most effective diagnostic and therapeutic measure for salivary gland tumors, especially those that grow slowly. Resection with negative margins is the treatment of choice for EMC; use of adjuvant radiotherapy is controversial.

Benign myoepithelioma of the soft palate: an unusual clinical entity.

Myoepitheliomas are rare benign tumours that affect the exocrine glands and are sporadically located in the salivary glands. The most common location of myoepithelioma in the oral cavity is the parotid gland and it is seldom encountered in the palate. The diagnosis of this entity is challenging since its clinical presentation may resemble those of more common neoplasms, rendering a complex histopathological diagnosis. The aim of the present case report is to describe an unusual case of myoepithelioma of the soft palate in a male patient, which developed as an asymptomatic, slowly growing mass. The tumour was assessed with histopathological examination and the diagnosis was verified via immunohistochemistry. Finally, the treatment included surgical resection of the tumour and no signs of recurrence were noted 2.5 years after the surgical procedure. Early diagnosis and treatment plays an important role in the prognosis of this pathological entity.

Primary parasagittal myoepithelioma in a paediatric patient: review of the literature and illustrative case.

Myoepithelial tumours are a rare form of salivary gland neoplasm, and their occurrence in the central nervous system is exceedingly rare. The authors report the case of an 18-year-old Filipino man presenting with headache and weakness, and on imaging showing an extensive parasagittal tumour at the left posterior parietal area with extracalvarial extension. There was no systemic disease. The patient underwent surgery to excise the tumour, with histopathology showing findings consistent with myoepithelioma. There was no further treatment, given the benign histology of the lesion, but there was recurrence after 8 months. Repeat surgery was done for the patient and he is for adjuvant radiotherapy. This appears to be the 10th reported case of a central nervous myoepithelioma, and the first case in the Philippines of a primary parasagittal myoepithelioma in a paediatric patient. Further information is needed to provide diagnostic and therapeutic recommendations.

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.

Soft Tissue Myoepithelioma of the Shoulder.

Soft tissue myoepitheliomas are often misdiagnosed due to their rarity. Herein, we describe a case of soft tissue myoepithelioma of the shoulder. A 72-year-old woman had a suspected sarcoma on her shoulder and under-went open biopsy. She was referred to our hospital, where the tumor was widely resected and the diagnosis of myoepithelioma was histologically confirmed. No recurrence has been observed in the 3 years since the sur-gery. Careful and prompt planning is necessary for the effective treatment of myoepithelioma.

18F-FDG PET/CT Findings in a Rare Myoepithelial Carcinoma Arising in the Parapharyngeal Space.

Myoepithelial carcinoma is an exceedingly rare malignant neoplasm that most frequently occurs in the salivary gland. We here report a case of myoepithelial carcinoma in a 57-year-old man. Unenhanced and contrast-enhanced CT scans showed an ill-defined, heterogeneous, contrast-enhancing mass in the left parapharyngeal space, which suggested malignancy. F-FDG PET/CT showed a hypermetabolic mass and multiple FDG-avid lymph nodes in the bilateral cervical regions. An incision biopsy was performed, and the pathological examination confirmed the mass to be a myoepithelial carcinoma.

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

BACKGROUND: Pulmonary epithelial-myoepithelial carcinoma is a very rare type of salivary gland lung tumor. No standard treatment plan yet. This article intends to analyze the clinical characteristics of pulmonary epithelial-myoepithelial carcinoma and discuss the diagnosis and treatment of pulmonary epithelial-myoepithelial carcinoma. METHODS: The clinical data of a patient with pulmonary epithelial-myoepithelial carcinoma were analyzed and other relevant clinical literatures were reviewed. RESULTS: Epithelial cells immunohistochemically expressed cytokeratin and myoepithelial cells immunohistochemically expressed SMA and S-100. The next-generation sequencing was mainly HRAS gene mutation and the express of PD-L1 protein was negative. CONCLUSIONS: Most of the patients with Pulmonary epithelial-myoepithelial carcinoma have a good prognosis. Diagnosis mainly depends on microscopic examination and immunohistochemistry. The treatment of pulmonary epithelial-myoepithelial carcinoma is mainly surgical resection. The effect of radiotherapy and chemotherapy is not clear.

Epithelial myoepithelial carcinoma of the parotid gland: A rare tumor with oncocytic changes.

Epithelial myoepithelial carcinoma (EMC), a very rarely seen, low-grade, malignant, salivary gland tumor is most commonly located in the parotid gland followed by the submandibular gland. It is more often observed in females and in the 6th decade of life. Although primary treatment of the tumor is surgical resection, adjuvant radiotherapy may be applied to the adjacent area or close follow-up can be done if the surgical margin is closed. Patients must be followed up closely for recurrence and metastasis. Physical and radiological examinations (USG and MRI) should be performed to see for any recurrence in the operated area during the first year for every 2-3 months. This study presents the clinical, radiological, and pathological characteristics of a 59-year-old female patient with low-grade, oncocytic variant of EMC located in the left parotid gland.

Foot plantar soft tissue malignant myoepithelioma tumor: Case report and review of the literature.

The spectrum of myoepithelial tumors usually occur in the salivary glands, and occasionally in the skin, breast, upper aero-digestive tract, and soft tissues. The myoepithelial tumors have no sex predominance and usually present within a wide range of age of distribution around the third and fifth decades. We describe a 12 year old male patient with primary malignant myoepithelial tumor in the foot plantar soft tissues. Including this tumor with unusual location, and age of presentation is essential in the differential diagnosis for soft tissue tumors in the pediatric population.

[Recurrent maxillary sinus pleomorphic gonadoma into myoepithelial carcinoma: a case report].

Summary A 44-year-old woman with left nasal obstruction and facial numbness for 4 months was admitted to hospital. The patient did not have amblyopia, vision loss, runny nose with blood, dizziness ,headache or other discomfort.In 1991 and 2001, the patient were pathologically diagnosed as pleomorphic adenomas.CT of nasal cavity and paranasal sinuses showed that in the left maxillary sinus there was an about 4.4 cm×4.5 cm×4.7 cm large mass soft tissue density, showing expansive growth protruding into the left orbital floor.MRI showed that the lumped short T1 signal was seen in the left maxillary sinus and the linear long T1 signal was seen in the left nasal cavity, and the liquid accumulation signal foci could be seen in the left maxillary sinus.Postoperative pathological findings: （left maxillary sinus mass） Combining morphology, immunohistochemical results and medical history, consistent with pleomorphic adenoma carcinogenesis （cancer in pleomorphic adenoma）, carcinogenesis type is myoepithelial carcinoma.

Basal cell adenoma and myoepithelioma of the parotid gland: patterns of enhancement at two-phase CT in comparison with Warthin tumor.

PURPOSE: Early enhancement and a washout pattern are reported to be the characteristic imaging features of Warthin tumor (WT). The purpose of this study was to evaluate the enhancement patterns of basal cell adenoma (BCA) and myoepithelioma (ME) of the parotid gland on two-phase computed tomography (CT), compared with WT. METHODS: We retrospectively evaluated two-phase CT examinations of histologically proven 19 BCAs, 12 MEs, and 23 WTs of the parotid gland. In all patients, CT scans were obtained at early and delayed phases with scanning delays of 40 and 180 s, respectively. We measured the attenuation values on each phase of CT scans and calculated washout attenuation and relative percentage enhancement washout ratio. From the data acquired, we statistically compared the enhancing characteristics among three tumor groups. RESULTS: Based on the results of washout attenuation and relative percentage enhancement washout ratio, 15 (79%) of 19 BCAs, 9 (75%) of 12 MEs, and 23 (100%) of 23 WTs demonstrated a washout pattern of enhancement on two-phase CT scans. Despite variations of the individual tumors, both parameters revealed no significant difference among three tumor groups. CONCLUSION: BCAs and MEs of the parotid gland frequently show early enhancement and a washout pattern on two-phase CT, which can be indistinguishable from WTs in the majority of cases.

Myoepithelial carcinoma of tibia mimic giant cell tumor: a case report with emphasis on MR features.

Intraosseous myoepithelial carcinoma is an extremely rare type of bone tumor that most often presents in the long tubular bones, but also occurs in small tubular bones and the axial skeleton. We report the radiographic images and complete magnetic resonance (MR) features of a 44-year-old male with right knee pain of 7 months' duration. The radiographic findings and convention MR images indicated a giant cell tumor of the bone. The dynamic contrast-enhanced images showed a patent with the early wash-in and early wash-out usually noted in a giant cell tumor of the bone. Only water restriction on diffusion-weighted imaging (DWI) showed the malignant impression. Care should be taken when conventional images indicate giant cell tumor of the bone, as intraosseous myoepithelial carcinoma, although rare, can mimic this more common diagnosis. Further studies with DWI are warranted.

Clear cell, giant myoepithelioma of tongue base: a diagnostic and surgical challenge.

Clear cell variant is a rare histological type of myoepithelioma seen in parotid and soft palate. This article describes clear cell variant of myoepithelioma in the tongue base, which has not been reported in the literature so far. A 34-year-old man presented with dysphagia and foreign body sensation of throat. Video laryngostroboscopy using a 70° rigid telescope showed a smooth globular mass in the oropharynx arising from the tongue base. Based on clinical and radiological findings, the lesion was considered as benign. Fine needle aspiration cytology was not attempted fearing risk of bleeding, aspiration and airway compromise. Hence, an excisional biopsy followed by definitive histopathological examination without frozen section was planned. The patient underwent coblator-assisted excision and subsequently sent for histopathological analysis. There were cuboidal cell nests with abundant clear cytoplasm which stained positive for p63 by immunohistochemistry. This helped in establishing the diagnosis of clear cell myoepithelioma.

EWSR1-PBX3 fused myoepithelioma arising in metatarsal bone: Case report and review of the literature.

Intraosseous myoepithelial tumors are very rare. Due to the low incidence and diverse histologic features, accurate diagnosis is challenging, necessitating ancillary immunohistochemistry. Moreover, genetic abnormality in this tumor was not revealed until recently. Although EWSR1 translocation is involved in half of the cases of intraosseous myoepithelioma, only a few cases have indicated its counterpart gene. We herein describe a case of intraosseous myoepithelioma with a novel localization in the fourth metatarsal bone of a 36-year-old female. Cytogenetic analysis using next generation sequencing detected a rare EWSR1-PBX3 fusion. Next generation sequencing could be useful in understanding the cytogenetic characteristics of intraosseous myoepithelioma, and in obtaining an accurate diagnosis of this rare condition.