Intraosseous myoepithelioma of the maxilla: clinicopathologic features and therapeutic considerations

Central Myoepithelioma of the Maxilla

Myoepithelioma is a benign salivary gland tumor. Central myoepitheliomas are very rare. The aim of this report was to describe a case of maxillary myoepithelioma. A 14-year-old female patient presented with an multilocular lesion in the anterior maxilla, with nearly 8 months of duration. The lesion was asymptomatic, and the patient's dental history was unremarkable. The diagnostic hypothesis was an odontogenic tumor. Biopsy specimen consisted of nests of plasmacytoid cells in a myxoid stroma without duct formation. No cellular atypia or bone and cartilage formation were noted. The neoplastic cells were positive for Pan-cytokeratin, S100, CK7, and CK8. The final diagnosis was myoepithelioma. The patient was treated by surgical excision followed by bone curettage, and no signs of recurrence were found after 8 years of treatment.

Benign myoepithelioma of the hard palate: a clinical and histological diagnostic challenge. Case report and literature review

Introduction: Myoepithelioma (ME) is a rare salivary gland tumor. Constructed aroung a clinical case, this article aims to gather up up-to-date epidemiological, clinical and histological data about myoeptihelioma with emphasis on the diagnostic approach and differential diagnoses, paraclinical exams and the main histological features reported for its characterization. Observation: A 41-year-old female, presenting a 1-year slowly enlarging palatine nodule was referred to the Oral Pathology Consultation. Clinical data and paraclinic examination were non-specific. A thorough histological examination, comparing clinical data with cyto-architectural and immunostaining profile of the tumor allowed a positive diagnosis of ME. Discussion: The clinical aspect of ME is close from other more frequent tumors within the same areas. Accordingly, its discovery is often incidental and its diagnosis histological. ME display variable architecture and composition, requiring full tumor examination for proper diagnosis. When benign, ME act as mixed tumor regarding local extension, prognosis and recurrence. Malignant ME behaves as a low-grade malignant tumor with metastatic potential. Conclusion: Despite its rarity, ME should be hypothesized in front of a palatine nodule. Clinician and pathologist should be particularly cautious regarding nature, malignancy and follow-up of this tumor, since few data are up-to-now available.

HPV epigenetic mechanisms related to Oropharyngeal and Cervix cancers

Human Papilloma Virus infection is very frequent in humans and is mainly transmitted sexually. The majority of infections are transient and asymptomatic, however, if the infection persists, it can occur with a variety of injuries to skin and mucous membranes, depending on the type of HPV involved. Some types of HPV are classified as high oncogenic risk as associated with the onset of cancer. The tumors most commonly associated with HPV are cervical and oropharyngeal cancer, epigenetic mechanisms related to HPV infection include methylation changes to host and viral DNA and chromatin modification in host species. This review is focused about epigenethic mechanism, such as MiRNAs expression, related to cervix and oral cancer. Specifically it discuss about molecular markers associated to a more aggressive phenotype. In this way we will analyze genes involved in meiotic sinaptonemal complex, transcriptional factors, of orthokeratins, sinaptogirin, they are all expressed in cancer in a way not more dependent on cell differentiation but HPV-dependent.

Myoepithelial Tumors of Bone

Myoepithelial tumors (METs) of bone (BMETs) are a rare but distinct tumor entity. METs that are cytologically benign are termed myoepitheliomas; METs with malignant histologic features are called myoepithelial carcinomas. BMETs have a wide age range, may involve any part of the skeleton, and have a variable spindle cell and epithelioid morphology. Bone tumors to be considered in the differential diagnosis are discussed. Additional techniques are indispensable to correctly diagnose BMETs. By immunohistochemistry, BMETs often express cytokeratins and/or EMA together with S100, GFAP, or calponin. Half of BMETs harbor EWSR1 (or rare FUS) gene rearrangements with different gene partners.

Primary intra-osseous myoepithelioma of phalanx mimicking an enchondroma

Myoepitheliomas (MEs) are uncommon tumours of the soft tissue with an intermediate biological behaviour and uncertain differentiation. Primary intra-osseous MEs are rare and occur predominantly in the axial and proximal appendicular skeleton in middle-aged patients. The morphological variation of the tumour cells and stromal metaplasia may cause considerable diagnostic confusion, especially when it occurs in an unusual location. A wide panel of immunohistochemical markers is required to exclude other histological mimics. A 37-year-old male presented with a recurrent swelling in the right middle finger for 1-month duration. Radiographic images showed an expansile, lytic, intra-osseous lesion with high signal intensity on T2W fat-suppressed MR images in the proximal phalanx of the right middle finger without cortical breach, highly suggestive of an enchondroma. Histopathology revealed a lobulated tumour comprising of polygonal to spindle cells in groups and cords in a chondromyxoid stroma. No cellular atypia was noted. The tumour cells were immunopositive for epithelial membrane antigen (EMA), p63, S100 and smooth muscle actin (SMA), compatible with the diagnosis of an intraosseous ME. The proximal phalanx of the right middle finger was excised, revealing a similar tumour, and the patient has been on regular follow-up for the last 18 months without any recurrence. Primary intra-osseous MEs are extremely rare, and this is the second reported occurrence in small bones. A differential diagnosis of ME should be kept for enchondroma-like lesions of the bone for proper histopathological assessment and accurate diagnosis. Documentation of such cases and follow-up will enhance our understanding of their clinical course and prognosis.

Myoepithelial Tumors: An Update

Primary myoepithelial neoplasms of soft tissue are uncommon, and have been increasingly characterized by clinicopathologic and genetic means. Tumors are classified as mixed tumor/chondroid syringoma, myoepithelioma, and myoepithelial carcinoma, and they share morphologic, immunophenotypic, and genetic features with their salivary gland counterparts. However, soft tissue myoepithelial tumors are classified as malignant based on the presence of cytologic atypia, in contrast to the criterion of invasive growth in salivary gland sites. This review discusses the clinicopathologic and morphologic characteristics, distinct variants, and currently known genetic alterations of myoepithelial neoplasms of soft tissue, skin, and bone.

Recurrent benign myoepithelioma of the auricle

Myoepithelioma, a generally benign tumor comprised of myoepithlial cells, is an uncommon salivary gland tumor. Myoepithelioma originates primarily in the parotid gland, but several isolated cases have been described. Although myoepithelioma has a benign nature, but there is a potential risk of malignant change and recurrence in case of incomplete resection. We acknowledge that benign myoepithelioma originating from the auricle has not been reported in the English literature. We present a rare case of 27-year-old female who had recurrent benign myoepithelioma originating from the auricle and already had been given twice operations at the other clinic.

EWSR1-PBX3: a novel gene fusion in myoepithelial tumors

The genetics of myoepithelial tumors (ME) of soft tissue and bone have recently been investigated, with EWSR1-related gene fusions being seen in approximately half of the tumors. The fusion partners of EWSR1 so far described include POU5F1, PBX1, ZNF444 and, in a rare case, ATF1. We investigated by RNA sequencing an index case of EWSR1-rearranged ME of the tibia, lacking a known fusion partner, and identified a novel EWSR1-PBX3 fusion. The fusion was further validated by reverse transcriptase polymerase chain reaction and fluorescence in situ hybridization (FISH). To evaluate if this is a recurrent event, an additional cohort of 22 EWSR1-rearranged ME cases lacking a fusion partner were screened by FISH for abnormalities in PBX3 gene. Thus, two additional cases were identified showing an EWSR1-PBX3 gene fusion. One of them was also intraosseous involving the ankle, while the other occurred in the soft tissue of the index finger. The morphology of the EWSR1-PBX3 fusion positive cases showed similar findings, with nests or sheets of epithelioid to spindle cells in a partially myxoid to collagenous matrix. All three cases showed expression of S100 and EMA by immunohistochemistry. In summary, we report a novel EWSR1-PBX3 gene fusion in a small subset of ME, thereby expanding the spectrum of EWSR1-related gene fusions seen in these tumors. This gene fusion seems to occur preferentially in skeletal ME, with two of the three study cases occurring in intraosseous locations.

Malignant myoepithelioma of the humerus with a satellite lesion: a case report and literature review

We report an extremely rare case of malignant myoepithelioma presenting as a cortical osseous lesion on the humeral shaft with a satellite lesion. A 21-year-old man presented with persistent pain of the right upper arm after local trauma that had occurred 2 months earlier. Radiological examination revealed an expansile osseous tumour based on the cortex of the humeral shaft as well as a satellite lesion. En bloc resection was performed. Microscopic examination with immunohistochemical staining was used to establish a diagnosis of malignant myoepithelioma. Osseous malignant myoepithelioma occurring in long tubular bones rather than in bony structures with salivary tissue is extremely rare. Here, we demonstrate radiological and pathological features of a malignant myoepithelioma that developed in the cortex of the humeral shaft and review previously reported cases.