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Lipofibromatosis-like neural tumors (LPF-NT) are soft tissue tumors characterized by a lipofibromatosis-like pattern, CD34/PS100 positivity, and recurrent NTRK1 gene rearrangement. It occurs mainly in pediatric patients or young adults. We report here, the first case of LPF-NT in a middle-aged adult initially misdiagnosed as a myoepithelial tumor. LPF-NT may have a locally aggressive course but no recurrence was seen after complete surgeries, whereas metastatic diseases remain exceptional.

Aims Intracranial myxoid mesenchymal tumors (IMMTs) with fusions between EWSR1/FUS and CREB transcription factors have morphologic overlap with myxoid angiomatoid fibrous histiocytoma (mAFH) and myoepithelial tumor/carcinoma (MET/MEC). We aimed to study the clinicopathologic and genetic spectrum of extracranial IMMT-like tumors and their relationships with mAFH and MET/MEC. Methods Twelve extracranial tumors harboring EWSR1/FUS-CREB fusions across different histologic groups were characterized using RNA sequencing, FISH and/or RT-PCR. Results There were 4 IMMT-like neoplasms, 3 MET/MECs, and 5 mAFHs from the tibia (n=1), oral cavity (n=2), and soft tissues (n=9; 5 in the extremities), harboring EWSR1-ATF1 in 4 cases, FUS-CREM and EWSR1-CREM in 2 each, and EWSR1-CREB1 in 2. Multinodular growth, reticular/cording/trabecular arrangements, myxocollagenous matrix, and lymphocytic infiltrates variably prevailed among the 3 groups. mAFHs were characterized by cells with syncytial cytoplasm. IMMT-like neoplasms and MET/MECs shared cells with distinct boundaries, but only MET/MECs expressed GFAP and/or S100. MUC4 and ALK were expressed in some IMMT-like neoplasms (2/4; 2/4) and mAFH (2/5; 1/5). Pan-TRK reactivity was observed in two IMMT-like neoplasms with upregulated NTRK3 mRNA and one MEC. Local recurrences, typically ≥ 12 months postoperatively, developed in 2/3 IMMT-like neoplasms, 1/2 MET/MECs, and 0/4 mAFHs with follow-up. No definite associations were found between fusion types and histology, immunoprofile or outcome. Conclusions We demonstrated the similarities and differences among 3 extracranial myxocollagenous tumor groups sharing EWSR1/FUS-CREB fusions. Oral IMMT-like neoplasms harboring FUS-CREM or EWSR1-ATF1 and FUS-CREM-positive

Myoepithelial tumor is a rare form of cancer, mainly arising from the salivary glands and extremities. Due to its rarity, no formal treatment guidelines exist. Here we report a case of a male patient diagnosed with metastatic myoepithelial tumor which was successfully treated with an androgen-receptor (AR) antagonist (bicalutamide), based on the results of molecular testing. Six years after the initiation of bicalutamide, patient was diagnosed with metastatic prostate cancer. To our knowledge, this is the first case described in literature that demonstrate the effectiveness of anti-androgens in treating myoepithelial tumor. Vigilance should be maintained when screening these patients for prostate cancer as their 'true' prostate specific antigen levels might be masked by the ongoing endocrine therapy.

Myoepithelial tumor (MET) of bone is an unusual tumor of uncertain differentiation and histogenesis. Although its presence in various bones has been reported sparsely, the presentation in clivus as primary myoepithelial carcinoma (MEC) has never been reported. They resemble their salivary gland counterparts morphologically and immunohistochemically, but harbor distinct molecular phenotype. At present, moderate nuclear atypia is the acceptable criteria to differentiate MEC from myoepithelioma. Because of their rarity, wide histopathological spectrum, and intraosseous location, MET of bone is easily confused with a variety of primary bone and cartilaginous tumors. Application of immunohistochemistry and, if required, molecular testing are required for making a correct diagnosis. In this article, we describe an extremely rare case of a primary MEC arising from the clivus, which owing to unusual location and immunohistochemical profile was diagnostically challenging.

Soft-tissue myoepithelioma (STM) is an extremely rare benign tumor with predominant occurrence in head, neck, pelvic girdle and limbs. These tumors lack specific clinical and morphological features and can easily be confused with more common neoplasms. It may lead to incorrect diagnosis and management. Here, we present a clinical case of a young man with retroperitoneal STM which simulated a pancreatic tumor and required a distal pancreatectomy. Performed literature review highlights current data about clinical, morphologic, immunohistochemical and genetic evaluation, treatment and prognosis of STM. J Med Cases. 2020;11(1):16-21 doi: https://doi.org/10.14740/jmc3407

Overall, neonatal cancer is uncommon. Because of its rarity and heterogeneity, diagnosis can be challenging. We report a unique case of a myoepithelial carcinoma in a 7 week old girl. Molecular diagnostic workup revealed a EWSR1-KLF15 gene fusion which was previously described in only six cases of myoepithelial tumors so far. All cases occurred in children and adolescents. To our knowledge, this is the first report of a congenital EWSR1-KLF15 fusion positive myoepithelial tumor in an infant.

Hyalinizing clear cell carcinoma (HCCC), also known as clear cell carcinoma, not otherwise specified [CCC, (NOS)], is a rare minor salivary gland tumor characterized by proliferation of clear cells, organized in trabecular cords, or solid nests within loose to densely hyalinized stroma. It is considered a diagnosis of exclusion by the World Health Organization (WHO) because other salivary tumors may also have a clear cell component. Hence, there is a wide differential diagnosis. EWSR1-ATF1 gene rearrangements are fairly specific for this tumor, however, one of the recent studies have described its presence in clear cell odontogenic carcinoma (CCOC) one of its histologic mimickers. EWSR1 and CREM fusions have recently been described in these tumors but its importance is still not well described. Here we present a case of a 33-year-old woman who presented with a recurrent lesion of the soft palate. Her initial lesion was resected and diagnosed as low-grade myoepithelial tumor. Surgical margins at the time of initial resection were positive and the re-excision was recommended but the patient did not undergo surgery. Two years later, local recurrence at the same site was found and an excision was performed yielding negative margins. Histopathologic examination revealed features consistent with hyalinizing clear cell carcinoma. The patient remains disease free 1 year after the re-excision. The pathology, clinical characteristics, differential diagnosis and treatment of hyalinizing clear cell carcinoma are reviewed.

Malignant myoepithelial tumors are a type of recently recognized tumor that occur primarily in soft tissue characterized by myoepithelial elements without ductal differentiation. It appears that this type of tumor may be related to parachordoma or mixed tumor. However, only a small number of cases have been described in the submandibular, parotid and accessory glands, and bone is an extremely rare site for myoepithelial tumor presentation. We herein report a rare case of a 56-year-old woman diagnosed with primary malignant myoepithelial tumor originating in the tibia. Histologically, the tumor was composed of a nodular spindled and epithelioid neoplasm with mild to moderate nuclear pleomorphism embedded within variably collagenous, myxoid and chondromyxoid stroma. Immunohistochemistry staining showed tumor cells that were strongly positive for S100 protein, epithelial membrane antigen, vimentin and focally positive for p63 and cytokeratins (AE1/AE3); they were negative for desmin, smooth muscle actin, HMB45, Melan-A, CD99 and bcl2. This is all consistent with the phenomenon of myoepithelial differentiation. Additionally, Fluorescence in Situ Hybridization (FISH) was shown to be positive for EWSR1 translocation. Ultimately, the final diagnosis was primary myoepithelial carcinoma of bone. The patient was free of disease after three years of follow-up. In this article, we have shared our experience in documenting this rare medical entity, to clarify the crucial need for distinguishing myoepithelial carcinoma from primary benign and malignant bone and cartilage forming tumors. Keywords: Myoepithelial carcinoma, Rare bone tumors

Background Despite extensive immunohistochemical (IHC) and molecular studies combined with morphologic findings, a group of round/ovoid cell tumors histologically similar to Ewing sarcomas (ES) but lacking EWSR1-rearrangements may remain unclassifiable. Design We retrospectively analyzed 41 Ewing-like tumors (formalin-fixed, paraffin-embedded) previously determined as negative or non-informative for EWSR1-rearrangements by FISH and/or RT-PCR. A new histopathology revision and additional IHC and molecular analyses were carried out in order to investigate whether additional IHC and/or molecular testing in combination with the morphological findings may help in reaching a definitive diagnosis. Results Almost all the tumors (n = 40) involved soft tissue and/or bone and half the patients died of disease. In the archival cases all diagnoses were Ewing sarcoma (ES), Ewing-like sarcoma (ELS), myoepithelial tumor and undifferentiated sarcoma (US). In the new review all the tumors were re-classified as, ES (n = 16), Ewing-like tumor with EWSR1 rearrangement and amplification and possible EWSR1-NFATC2 gene fusion (n = 1), CIC-rearranged sarcomas or undifferentiated sarcoma, most consistent with CIC-rearranged sarcoma (n = 7), sarcoma with BCOR-alteration or undifferentiated sarcoma, consistent with BCOR-associated sarcoma (n = 3), neuroblastoma (n = 2), unclassifiable neoplasm with neuroblastic differentiation (n = 1), malignant rhabdoid tumor (n = 2), lymphoblastic lymphoma (n = 1), clear cell sarcoma of the gastrointestinal tract (n = 1), small cell carcinoma (n = 1), sclerosing rhabdomyosarcoma (n = 1), desmoplastic small round cell tumor (n = 1), malignant peripheral sheath nerve tumor (n = 1), poorly-differentiated synovial sarcoma (n = 1), Possible gastrointestinal stromal tumor/GIST with predominant round cells (n = 1) and possible SMARCA4-deficient-sarcoma (n = 1). NKX2.2, ETV4 and BCOR immunoreactivity was observed in all ES, CIC-rearranged sarcomas and sarcomas with BCOR alteration, respectively. CIC-rearrangement by FISH was observed in many of the CIC-rearranged sarcomas. Conclusion Our analysis of 41 Ewing-like tumors confirms that there may be a significant pathological and IHC overlap among Ewing-like tumors, with prognostic and therapeutic impacts. Additional IHC (NKX2.2, ETV4 and BCOR) and molecular studies including FUS, CIC or BCOR analysis may support the final diagnosis when FISH or RT-PCR fail to detect EWSR1-rearrangements. Any molecular findings should always be interpreted in relation to the specific clinical and pathological context.

Pleomorphic adenoma (PA) is the most common benign salivary gland neoplasm, mainly involving the parotid followed by the minor salivary glands of the palate and the submandibular glands. The aim of this study is to report 3 cases of intraoral PA that presented uncommon histopathologic features. Case 1 occurred in the lower lip, case 2 occurred in the palate, and case 3 occurred in the posterior alveolar ridge. Clinically, all cases presented as an asymptomatic nodule. Microscopically, case 1 showed extensive bone metaplasia with few myoepithelial cells and ducts. Solid myoepithelial tumor with scant ducts was observed in case 2. Case 3 exhibited exuberant squamous metaplasia. In conclusion, PA can become a diagnostic challenge, and the knowledge of this diversity of microscopic pattern is essential to reach the correct diagnosis.

Intracranial myoepithelial tumors are extremely rare with

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.

Adamantinoma of the long bones is an exceedingly rare and slow-growing tumor that affects the diaphysis of long bones, particularly the tibia. Based on the pattern of the epithelial cell component and the presence or absence of the osteofibrous dysplasia-like element, several histological variants have been described, such as (i) tubular (the most frequent), (ii) basaloid, (iii) squamous, (iv) spindle variant, (v) osteofibrous dysplasia –like variant, and (vi) Ewing’s sarcoma – like adamantinoma (the least frequent). The diagnosis may be challenging since this tumor may be mistakenly interpreted as carcinoma, myoepithelial tumor, osteofibrous dysplasia, and vascular tumor. We report the case of a 41-year-old male who presented with swelling over the right leg associated with pain. The X-ray showed a lytic lesion of the right-sided tibia. The diagnosis of adamantinoma was made based on the clinico-radiological, histomorphology, and immunohistochemical findings. Histologically, classic adamantinoma is a biphasic tumor characterized by epithelial and osteofibrous components in varying proportions and differentiating patterns. The diagnosis can be confirmed by immunohistochemistry for demonstrating sparse epithelial cell nests when the radiological features are strongly consistent with adamantinoma. This case is highlighted because the epithelial component can lead to a misdiagnosis, particularly when the clinico-radiological features are overlooked. Adamantinoma of long bones has the potential for local recurrence and may metastasize to the lungs, lymph nodes, or other bones. The prognosis is good if early intervention is taken.

Introduction/Objective A 38-year-old female without a history of trauma and malignancy presented with left knee pain and swelling for two weeks. MRI and PET scan find a left knee mass arising from the bone along the medial metaphysis of the distal femur. She underwent femur resection, and the specimen was sent for pathology evaluation. Methods Grossly, the cut surface of the sample revealed a 4.5 x 2 cm area of hemorrhagic softening of the bone with adjacent soft tissue nodules. Microscopically, the tumor showed biphasic or multiphase morphologic features, prominently presented with areas showing well-differentiated epithelial features and other areas with spindling and sheets of tumor cells. Areas suspicious for a vascular invasion were seen at the periphery of the soft tissue extension of the tumor. Immunohistochemistry stains showed the tumor cells are positive for vimentin, AE1/3, EMA, CK7, CK19, GATA3, and BRST2; and are negative for S100, HMB45, GFAP, Calponin, CDX2, PAX8, WT1, P63, CD34, and ER. The molecular test showed positive for the ESWR1 gene but negative for SYT gene translocation. Results A diagnosis of primary myoepithelial carcinoma of bone extension into surrounding soft tissue was made. Conclusion The most challenging differential diagnosis for this case is metastatic breast cancer. Many of the positive epithelial stains distinctly highlight the epithelial featured geographic areas sparing the background spindled stroma. The positive staining of GATA3 and BRST2, two commonly used breast linage markers, is unusual and not known in myoepithelial carcinoma. In light of the EWSR1 positive and SYT FISH negative results, combined with the morphologic features, locations as well as negative PET scan against its breast origins. Although many myoepithelial markers, such as S100, Calponin, P63, and GFAP were negative, make this case very unique. The molecular diagnosis is the mainstay for this final diagnosis.

Neoplasms of low malignant potential represent a group of rare tumors of diverse differentiation that behave mostly in a benign fashion but have unpredictable capacity to recur locally or at distant sites. The majority of these tumors can occur in other sites of the body but can present as incidentally discovered pulmonary masses mimicking pulmonary malignant tumors. Patients are often asymptomatic. Aspiration biopsy or small biopsies are necessary to rule out malignancy. Therefore it is important for cytopathologists and cytotechnologists to be familiar with the cytological features of these rare neoplasms and their diagnostic pitfalls.

Background: Primary sebaceous carcinoma of the parotid gland is extremely rare, and because of its rarity, clinicopathological characteristics and histogenesis are not fully understood. Methods: Here, we report a patient who presented with a left infra-auricular painless mass. We present the histological features and discuss possible optimal treatments based on previous literature. Results: The mass was suspected to be a myoepithelial tumor or possibly a pleomorphic adenoma. Initially, the mass was resected with preservation of the facial nerve, but this caused facial palsy. Because the histological examination showed a sebaceous carcinoma and a part of the mass could be remaining on the facial nerve, additional surgery was performed, and the facial nerve was reconstructed with cervical nerve. Follow-up after 7 months showed no sign of recurrence of metastasis. Conclusion: We encountered a rare sebaceous carcinoma of the parotid gland. Additional surgery was performed because preoperative diagnosis was difficult.

Basal cell carcinoma is the most common skin cancer. Myoepithelial cells are specialized epithelial cells. Basal cell carcinoma with myoepithelial differentiation is a rare tumor. A 71-year-old man with a basal cell carcinoma with myoepithelial differentiation that presented as an asymptomatic red papule of two months duration on his forehead is described. Including the reported patient, this variant of basal cell carcinoma has been described in 16 patients: 11 men and five women. The patients ranged in age at diagnosis from 43 years to 83 years; the median age at diagnosis was 66 years. All of the tumors were located on the face-most were papules or nodules of less than 10 x 10 mm. Their pathology demonstrated two components: one was that of a typical basal cell carcinoma and the other was myoepithelioma-like in which the tumor cells were plasmacytoid or signet ring in appearance and contained abundant eosinophilic cytoplasm or hyaline inclusions or both. The myoepithelial tumor cells had variable immunohistochemical expression that included not only cytokeratin but also actin, glial fibrillary acid protein, S100, and vimentin. The most common clinical impression, prior to biopsy, was a basal cell carcinoma. The pathologic differential diagnosis included cutaneous mixed sweat gland tumor of the skin, myoepithelioma, myoepithelial carcinoma, and tumors that contain a prominent signet ring cell component (such as metastatic gastrointestinal and breast carcinoma, melanoma, plasmacytoid squamous cell carcinoma, and T-cell lymphoma). Mohs micrographic surgical excision, with complete removal of the tumor, was recommended for treatment of the carcinoma.

Myoepithelial carcinoma is an uncommon malignant tumor of the lacrimal gland, composed of neoplastic myoepithelial cells with an infiltrative growth. The present study describes a unique case of progressive proptosis and blindness of the right eye in a 68-year-old woman following total tumor removal for lacrimal pleomorphic adenoma. Clinical study, surgical exploration, and pathology revealed lacrimal myoepithelial carcinoma ex recurrent pleomorphic adenoma, T2N0M0. In addition, 18 cases of lacrimal myoepithelial tumor that have been previously described in the literature are reviewed. The application of clinical, radiological, histopathologic, and immunohistochemical investigations may help to reach the definite diagnosis. Criteria for malignancy of lacrimal myoepithelial tumor should be the same as salivary myoepithelial tumor diagnosis, until long-term outcome data for a larger number of patients with lacrimal myoepithelial carcinoma become available.

Salivary glands may give rise to a wide spectrum of different tumors. This review concentrates on 4 salivary gland tumors that have been accepted in the recent literature as new neoplastic entities: mammary analog secretory carcinoma, cribriform adenocarcinoma of minor salivary glands (CASG), sclerosing polycystic adenosis/adenoma (SPA), and the mucinous/secretory variant of myoepithelioma. Mammary analog secretory carcinoma is a distinctive low-grade malignant salivary cancer that harbors a characteristic chromosomal translocation, t(12;15) (p13;q25), resulting in an ETV6-NTRK3 fusion. Cribriform adenocarcinoma (CASG) is a distinct tumor entity that differs from polymorphous low-grade adenocarcinoma by location (ie, most often arising on the tongue), by prominent nuclear clearing, differing alterations of the PRKD gene family, and clinical behavior with frequent metastases at the time of presentation of the primary tumor. Early nodal metastatic disease is seen in most cases of CASG; yet, they are still associated with indolent clinical behavior, making it a unique neoplasm among all low-grade salivary gland tumors. SPA is a rare sclerosing tumor of the salivary glands characterized by the combination of cystic ductal structures with variable cell lining including vacuolated, apocrine, mucinous, squamous, and foamy cells, by prominent large acinar cells with coarse eosinophilic cytoplasmic zymogen-like granules, and by closely packed ductal structures, surrounded by a peripheral myoepithelial layer and stromal fibrosis with focal inflammatory infiltrates. SPA frequently harbors intraductal epithelial dysplastic proliferations ranging from mild dysplasia to severe dysplasia/carcinoma in situ. Moreover, SPA has been proven to be a clonal process by HUMARA assay and is associated with considerable risk of recurrence. Therefore, on the basis of all these newly recognized findings, we believe that SPA is likely a neoplasm, and we suggest the name sclerosing polycystic adenoma. The mucinous variant of myoepithelioma is a myoepithelial tumor with foci of prominent cytoplasmic clearing frequently containing intracellular mucin material and having signet-ring morphology. info:eu-repo/semantics/publishedVersion

Primary soft tissue myoepithelial tumor, an uncommon variant of myoepithelial neoplasms, has been recently described in reviewed literature. We report a rare case of soft tissue myoepithelial carcinoma in a 60 year old male patient presented as a unilateral neck mass. MRI showed a large lobulated infiltrating heterointense mass with central necrotic area involving left parapharyngeal space. Histopathological examination revealed multilobular growth pattern of epitheloid cells with marked atypia and frequent mitosis. Immunohistochemistry was reactive for p63, calponin, CD10, pancytokeratin, EMA and podoplanin with high (40%) proliferative labeling index. Except for the presence of increased malignant cell population, soft tissue myoepithelial carcinoma mimics their salivary gland counterpart in clinical and biologic behavior. Rarity in head and neck region (only 16%) and heterogeneity in cellular morphology and architectural patterns, may lead to misdiagnosis of extraglandular myoepithelial carcinoma. So, careful and meticulous observation of both histopathologic and immunophenotypic features are essential for correct diagnosis of such entities.

Malignant myoepithelioma of salivary gland which is also known as myoepithelial carcinoma is a rare disease. It has a relatively poor clarification of its biologic behavior, clinicopathologic features and immunohistochemical profile. Presentation may be the same as other benign salivary gland tumors. A high index of suspicion is required to diagnose this rare but malignant condition early and this is especially imperative when there is a recurrent tumor with histopathological examination report of benign findings. We report a case of malignant myoepithelioma of right submandibular gland that underwent surgical excision with neck dissection and chemoradiotherapy without signs of recurrence after treatment.

Background Extraskeletal myxoid chondrosarcoma is a rare soft tissue sarcoma that has unusual ultrastructural and molecular features. However, unlike other soft tissue sarcomas, it does not have specific clinical symptoms or radiological features, which can make its diagnosis difficult. Nevertheless, extraskeletal myxoid chondrosarcoma has a rare gene fusion (EWSR1-NR4A3) that is useful for making a differential diagnosis. Case presentation A 43-year-old Japanese man presented with a soft tissue mass in his right thigh. A physical examination and radiography revealed a large soft tissue mass. During magnetic resonance imaging, the mass exhibited isointensity on T1-weighted images and high intensity on T2-weighted images, as well as gadolinium enhancement at the side edge of the partition structure. Thus, we considered a possible diagnosis of a malignant myxoid soft tissue tumor, such as myxoid liposarcoma, myxofibrosarcoma, or metastatic carcinomas, including myoepithelial tumor and neuroendocrine tumor, and performed an incisional biopsy to make a definitive diagnosis. The pathological findings revealed a lobulated tumor with a myxoid structure and atypical spindle-shaped cells that created eosinophilic cord-like forms. Immunohistochemistry revealed that the tumor was positive for S-100 and negative for synaptophysin, chromogranin A, and pan keratin (AE1/AE3). The percentage of Ki-67 was 10 % in the hot spot area. Based on these clinicopathological findings, we initially considered the possibility of a myxoid liposarcoma, although we did not observe any lipoblasts. Therefore, we considered the possibility of an extraskeletal myxoid chondrosarcoma. As this tumor is very rare, we searched for the EWSR1-NR4A3 gene fusion using fluorescence in situ hybridization, which confirmed the diagnosis of extraskeletal myxoid chondrosarcoma. Positron emission tomography-computed tomography did not identify any obvious metastases, and we performed radical resection of our patient’s vastus medialis and femur with a 3 cm margin. After the resection, we treated his resected femur using liquid nitrogen, and reconstructed his femur using autogenous fibula and plate fixation. No local recurrence or metastasis was observed at the 1-year follow-up. Conclusion Genetic testing is useful for diagnosing extraskeletal myxoid chondrosarcoma based on the presence of the EWSR1-NR4A3 gene fusion.

Benign and malignant tumours originating from myoepithelial cells are rarely seen in clinical practice. Myoepithelioma of the middle ear is a very rare condition. A 54-year-old woman was admitted to our department, complaining of ear fullness, otalgia, and tinnitus in the left ear beginning 4 years earlier. The tumor Diagnosed as the left ear benign myoepithelioma. The tumor was removed. The ossicles and tympanic membrane were preserved intact.

A case of benign myoepithelioma of the breast in a 55-year-old woman is described. The tumor was a well-circumscribed solid mass, measuring 13 x 12 mm. Histopathology indicated that the tumor was composed of entirely myoepithelial cells, which was confirmed by immunoreactivity to calponin and S-100. There was no ductal differentiation in the tumor, and staining for pan-cytokeratin and epithelial membrane antigen was weak and negative, respectively. Although the biological behavior of the tumor remains to be ascertained, the tumor was considered to be myoepithelioma with benign features due to mild nuclear pleomorphism, sparse mitotic figures, low Ki-67 labeling index and low S-phase fraction. Diagnostic confusion between benign myoepithelioma and other myoepithelial-rich cell tumors is possible. Considering the classification of myoepithelial tumor in the salivary glands, benign myoepithelioma of the breast may possess a different development process from adenomyoepithelioma.

A 6-year-old, castrated male Shiba-inu displayed a mass showing invasive growth in the external auditory canal of the left ear. Histologically, the tumor mass predominantly comprised spindle-shaped neoplastic cells, arranged in solid nests admixed with irregular tubulo-acinar structures, lined by cuboidal to polygonal neoplastic cells. Neoplastic cells had extensively infiltrated into deep tissues. No bone formation or chondroid matrix was observed in the tumor stroma. Both types of neoplastic cells showed nuclear atypia and high mitotic activities. Luminal epithelial elements were immunohistochemically positive for pan-cytokeratin and cytokeratin 8. Spindle-shaped cells showed intense immunoreactivity for vimentin, pan-cytokeratin and α-smooth muscle actin, indicating that spindle-shaped cells retained the original histological characteristics of myoepithelial cells. These findings were consistent with a diagnosis of ceruminous gland carcinoma with malignant proliferation of acinar epithelial and myoepithelial tumor cells, which rarely occurs in dogs. Following resection with wide surgical margins, no recurrence or metastases have been observed as of 6 months postoperatively.

Background Adamantinoma is a rare tumor of long bones that can be mistaken for a carcinoma, and numerous other lesions such as myoepithelial tumor, malignant mixed tumor of bone, fibrous dysplasia/osteofibrous dysplasia, and vascular tumors. Methods The histology and clinical features of 12 cases accrued from the surgical pathology files over a period of 23 years were analyzed. Results Of the 12 cases, 4 were men and 8 women, with a mean age of 30 years. Radiologically the tumor presented as a lytic, eccentric, intracortical lesion in the tibia. The histology revealed epithelial islands with basaloid, spindle, and squamous features on a background of fibrotic stroma. Three patients came back with local recurrences, and one of them developed pulmonary metastasis. Discussion In this article, an attempt is made to study the morphology, biology, and the differential diagnoses of adamantinoma of long bones. J. Surg. Oncol. 2006;93:429–433. © 2006 Wiley-Liss, Inc.

BACKGROUND Carcinoma arising in a mixed tumor, or carcinoma ex pleomorphic adenoma (CEPA), is an uncommon primary salivary gland neoplasm. Among the various types of carcinomas that can be seen histologically in a CEPA, myoepithelial carcinoma is one of the rarest forms. CASE A 76-year-old woman presented with an incidental parotid/parapharyngeal mass. Computed tomography-guide fine needle aspiration (FNA) showed a biphasic neoplasm with epithelial and stromal components consistent with pleomorphic adenoma (PA). However, in addition, a distinct population of discohesive atypical and pleomorphic cells with high nuclear/cytoplasmic ratio was noted in the background. In the cytopathologic diagnosis a suspicion was raised about a possible CEPA. Subsequent resection of the parotid mass confirmed the presence of low grade myoepithelial carcinoma arising in a PA. CONCLUSION Although uncommon, CEPA should be suspected on FNA when atypical cytomorphologic characteristics are observed. In rare cases a myoepithelial carcinoma also arises in a preexisting PA, necessitating an accurate interpretation for more definitive therapy.

A tumor was observed in the left mandible of a 3-year-old male Shih-Tzu dog. Histopathology revealed neoplastic alveolar proliferation of round cells, sarcomatoid proliferation of round to spindle-shaped cells and an existing parotid gland tissue around the tumor. A cancellous bone framework was also seen throughout the tumor. The tumor cells in the sarcomatoid area were positive and weakly positive for vimentin and cytokeratin, respectively, demonstrating their myoepithelial character. We diagnosed this tumor as a malignant mixed tumor of the salivary glands, because of the location of the tumor, its invasiveness into the surrounding tissue and the identification of both epithelial and myoepithelial tumor cells.

Intranasal pleomorphic adenoma is a rare neoplasm, and thus only one case report addressed immunohistochemical findings of this neoplasm. To define immunohistochemical features of intranasal pleomorphic adenoma, we studied three cases of the pleomorphic adenoma developed from the nasal septum. Subsequently, immunohistochemical reactivities of the tumor cells for various cytokeratins, glial fibrillary acidic protein (GFAP), S100 protein, alpha-smooth muscle actin (SMA), and vimentin were similar to those of pleomorphic adenoma of the parotid gland. The tumors examined in this study had different histological components, such as predominance of myxoid area, solid area, or tubuloductal structure, but immunoreactivity of both epithelial and myoepithelial tumor cells were the same in the tumors. Therefore, immunoreactivity of the tumor cells were the same among the intranasal pleomorphic adenoma having various histological components.

Malignant myoepitheliomas of the salivary gland are very rare tumors which may either arise de novo or develop in a pre-existing pleomorphic adenoma. We report a case of malignant myoepithelioma of the minor salivary gland that progressed from benign pleomorphic adenoma. The original pleomorphic adenoma was resected in 1979 (the '79 tumor). The first recurrent tumor was operated in 1995 (the '95 tumor). The '95 tumor was diagnosed as pleomorphic adenoma. Although the myoepithelial tumor component was more prevalent in the '95 tumor, histological features of the first recurrent tumor were similar to the '79 tumor. The second recurrent tumor showed more aggressive clinical features (the '98 tumor). It also showed massive growth of myoepithelial tumor cells with bone invasion, which led to the diagnosis of the '98 tumor as malignant myoepithelioma. With adequate surgical margin, the patient has been free from tumor recurrence for 20 months.

Myoepithelial cells of the breast and their hyperplasia is found in many benign conditions resulting in a spectrum of lesions of myoepitheliosis to myoepithelial carcinoma. We present a rare case of adenomyoepithelial adenosis in a 17-year-old female who presented with a palpable right breast lump. Although considered benign, adenomyoepithelial lesions have a high chance of recurrence due to inadequate excision. Recurrence and even metastasis are therefore important issues in the follow-up of adenomyoepithelial lesions.

Cutaneous myoepithelioma is a peculiar and recently recognized neoplasm exhibiting purely myoepithelial differentiation. These lesions affect different areas of the body, and are characterized by heterogenous morphological and immunophenotypical features. The majority of cutaneous myoepitheliomas behave in a benign fashion, however, the risk for local recurrence is higher with incomplete resection. A relatively newly described variant of myoepithelioma exhibits syncytial cytological features. The current study reports a case of cutaneous syncytial myoepithelioma presenting as a painless and papular skin lesion. The presence of the Ewing sarcoma RNA-binding protein 1 gene rearrangement in the present case supported the diagnosis of a myoepithelial tumor. The patient subsequently underwent local excision of the tumor and was followed up twice in the year after surgery. At the time of writing, the patient was alive and no recurrences had been identified. Furthermore, the current study discusses how this myoepithelial neoplasm may be distinguished from other problematic spindle or epithelioid cell tumors, particularly superficial dermal lesions.

ERG is immunoexpressed in vascular endothelial tumors, blastic extramedullary myeloid tumors, and tumors with ERG-involved translocation, such as prostate carcinoma or Ewing sarcoma. Recently, ERG immunoexpression was reported in an epithelioid sarcoma, which is a SMARCB1/INI1-deficient tumor, although epithelioid sarcoma is not associated with chromosomal translocations involving ERG and is categorized as a tumor with uncertain differentiation. SALL4 is essential for a proliferation and stabilization of embryonic stem cells. It was reported that SALL4 expression may aid in distinguishing epithelioid sarcoma from malignant rhabdoid tumor. We analyzed the frequency of ERG and SALL4 expressions in 80 SMARCB1/INI1-deficient tumors, including 45 epithelioid sarcomas (conventional-type, 24; proximal-type, 20), 17 malignant rhabdoid tumors, 5 atypical teratoid/rhabdoid tumors, 6 undifferentiated/unclassified sarcomas, 5 myoepithelial tumors, and 4 extraskeletal myxoid chondrosarcomas. We found that ERG expression was present in 18 of the epithelioid sarcomas (41%), including 13 conventional-type (54%) and 5 proximal-type (25%), whereas all 17 of the malignant rhabdoid tumors exhibited negative immunoreactivity. One atypical teratoid/rhabdoid tumor (20%), 1 myoepithelial carcinoma (20%), 1 undifferentiated/unclassified sarcoma (17%), and no extraskeletal myxoid chondrosarcomas (0%) also showed ERG expression. SALL4 expression was recognized in 5 epithelioid sarcomas (11%), 12 malignant rhabdoid tumors (71%), 2 atypical teradoid/rhabdoid tumors (40%), 4 undifferentiated/unclassified sarcomas (67%), 1 myoepithelial tumor (20%), and none of the extraskeletal myxoid chondrosarcomas (0%). Therefore, the evaluation of ERG and SALL4 immunoexpressions may be a useful diagnostic tool to distinguish epithelioid sarcoma, especially proximal type, from malignant rhabdoid tumor.

We report 19 unusual cases of mixed tumors and myoepitheliomas arising in soft tissues. The neoplasms occurred in 12 males and seven females. The age at diagnosis ranged from 2 to 83 years (mean 35, median 30). Eight tumors arose in the upper limb, six in the lower limb, three in the trunk, and two in the head and neck region. Three cases involved both dermis and subcutis; the remainder arose in subcutaneous (13 cases) or deep subfascial soft tissue (three cases). The most common presenting complaint was a painless swelling, with duration ranging from 2 weeks to 1 year (median 2.5 months). Microscopically, the tumors were predominantly well circumscribed and lobulated. Six cases showed a focally infiltrative margin. Cardinal morphologic features included nests, cords, and ductules of epithelioid cells and/or nests of spindled cells within a hyalinized to chondromyxoid stroma. One tumor was predominantly composed of myoepithelial cells and devoid of epithelial differentiation (i.e., ductules). Cytoplasmic hyaline inclusions were noted in two cases; squamous differentiation was seen in one case. Osteoid production and/or metaplastic bone was observed in three tumors. Chondroid differentiation (usually mature) was seen in four cases. Adipocytic differentiation was seen in two tumors. Mitotic activity was variable but generally scant; atypical mitotic figures were not identified. By immunohistochemistry, 16 of 16 cases expressed pan-keratin; 16 of 17 S-100 protein; six of 14 alpha smooth muscle actin (IA4); two of 10 muscle specific actin (HHF-35); two of 10 desmin; three of 11 glial fibrillary acidic protein; and three of 16 epithelial membrane antigen. Clinical follow-up was available in 10 patients and ranged from 6 months to 20 years (mean 4.25 years, median 2 years). Two patients developed local recurrence; metastasis to lung and lymph nodes were observed in two additional patients. Both of the latter patients died. We believe that these findings expand the concept of cutaneous mixed tumors to include neoplasms composed predominantly of myoepithelial cells and to include tumors arising in deeper subcutaneous and/or subfascial tissues. The clinical behavior of such neoplasms, when arising in soft tissues, may be difficult to predict but is most often benign; however, a minority of lesions metastasize. Until larger studies with longer follow-up are available, treatment and prognostication are probably best based on criteria used in comparable salivary gland tumors.

Objectives Epithelial myoepithelial carcinoma (EMC) of the lung is a very rare tumor that is characterized by biphasic differentiation of epithelial and myoepithelial cells. Current discussion about this entity focuses on the malignant potential of the tumor and the role of myoepithelial cells in diagnosis and patient prognosis. This study reports five EMC cases in the lung and discusses issues related to EMC prognosis. Materials and methods The five EMC cases were diagnosed and collected at the Samsung Medical Center (Seoul, Korea) from 1998 to 2012. Four patients with EMC were received a lobectomy and one patient was given a bronchoscopy to excise the tumor. All cases were evaluated with hematoxylin and eosin and immunohistochemical staining, which included S-100 protein, smooth muscle actin, TTF-1, cytokeratin, vimentin, and p27 analysis. Results and conclusion All cases revealed biphasic differentiation of epithelial and myoepithelial tumor cells with various stromal patterns. One of the cases contained predominantly myoepithelial and focal epithelial differentiation, and the tumor showed recurrence and metastasized to the chest wall. This was the first case of metastatic pulmonary EMC. Therefore, we suggest that EMC of the lung has a malignant potential, and that myoepithelial tumor cells may be associated with a pulmonary EMC prognosis.

Myoepithelial tumors of the soft tissues have only recently been described. Two cases of lower extremity malignant myoepithelial tumors are reported. One case of malignant mixed tumor overlying the gastrocnemius muscle was treated with wide local excision, but metastasized to regional lymph nodes 14 months after surgical excision. One patient with malignant myoepithelioma of the right lower leg was treated with limb amputation and is alive without disease at 46 months. A review of the literature discloses 120 additional cases of soft tissue myoepithelial tumors, 102 of which are myoepitheliomas and 18 are mixed tumors. Thirty-seven percent of the myoepitheliomas met the criteria for malignancy, and 33% of the mixed tumors were malignant. Of these, 30% had locally recurrent disease and 32% developed metastatic disease. Treatment benefit from chemotherapy and radiation therapy is unclear.

Background. Extraglandular myoepitheliomas are neoplasms that seldom occur in the soft tissue of the head and neck region. Misdiagnosis of these neoplasms as more aggres- sive tumors can lead to unnecessary treatment. Methods. We describe a myoepithelioma of cervical soft tissue. The histopathology of the tumor, its immunophe- notype, its differential diagnosis, and a review of the literature are presented. Results. Histopathologically, the tumor was composed of epithelioid cells with eosinophilic cytoplasm and eccentric nuclei arranged in cords and files. On immunohistochemical analysis, the cells expressed cytokeratin 14, calponin, glial fibrillary acid protein, and p63 and showed focal positivity for S-100 protein. Together, these markers identified the cells as myoepithelial type. A literature review identified only five cases of myoepithe- lioma in the soft tissue of the head and neck region in which detailed clinical information was provided. Conclusions. Myoepitheliomas can have cells with variable morphology arranged in different histologic patterns. Immuno- histochemical analysis is crucial for unequivocal diagnosis when myoepitheliomas occur in extraglandular locations. A 2004 Wiley Periodicals, Inc. Head Neck 26: 470-473, 2004

ObjectiveTo report a rare case of spindle cell sarcoma of submandibular salivary gland, with intraoral extension with pathological dilemma.Case reportA 40-year-old male presented with swelling and pain in right submandibular area since 1 year. Right submandibular gland excision with intraoral mass excision was done with reconstruction of floor of mouth. Postoperative histopathology was suggestive of low-grade malignant tumor with differential diagnosis of acinic cell tumor, vascular tumor and myoepithelial tumor. The immunohistochemistry report revealed spindle cell sarcoma with high degree of vascularity. Based on this report postoperative radiotherapy was planned.ConclusionAccording to literature, spindle cell sarcoma of submandibular salivary gland has not been reported yet. This case is presented for its uniqueness of its site, extension and histopathological dilemma.

SUMMARY: Although there seems to be a common stem cell for the two epithelial cell types in the breast, the vast majority of breast cancers exhibit a luminal phenotype. Pure myoepithelial carcinomas are rare. We report our findings of genetic alterations in these tumors. We have analyzed 10 cases of pure myoepithelial cell carcinomas using laser capture microdissection and comparative genomic hybridization. The mean number of changes was 2.1 (range 0 ‐ 4), compared with a mean of 8.6 (range 3.6 ‐13.8) in unselected ductal carcinomas. Common alterations included loss at 16q (3/10 cases), 17p (3/10), 11q (2/10), and 16p (2/10), regions also commonly deleted in ductal carcinomas. The single case in which both pure myoepithelial carcinoma and invasive ductal carcinoma was present showed 2 alterations in the myoepithelial tumor (losses at 17p and 17q), whereas the invasive ductal component showed 15 alterations (5 gains and 9 losses), including loss at 17p. The sharing of 17p loss in myoepithelial and ductal carcinoma is consistent with a common stem cell model in the breast. The relatively few genetic alterations in otherwise aggressive neoplasms suggests that myoepithelial tumors may be a good model for the delineation of genes important in breast tumorigenesis. (Lab Invest 2000, 80:831‐ 836).

High-grade invasive ductal carcinomas (IDCs) of the breast with large, central acellular zones on their cut surfaces are usually associated with the myoepithelial immunophenotype of carcinoma cells, which includes the expression of S-100 protein, alpha-smooth muscle actin, and keratin 14. To clarify the clinical significance of these features of IDCs, the authors compared the incidence of the myoepithelial immunophenotype immunohistochemically, patient prognosis, and metastatic sites of the tumor between 20 high-grade IDCs with large, central acellular zones and 40 control high-grade IDCs without these zones. The myoepithelial immunophenotype was detected in 16 IDCs (80%) with large, central acellular zones but in only seven IDCs (18%) without. The risk ratio of metastasis, especially in the brain and lung, and death from cancer were significantly higher (p = 0.0096 and p = 0.030) for the 20 IDCs with large, central acellular zones than for those without by Cox's univariate analysis. Using Cox's multivariate analysis, large, central acellular zones in IDCs were an indicator of high risk of brain and lung metastases and of death by cancer independent of nodal status and tumor size. Examination of large, central acellular zones and myoepithelial immunophenotype in high-grade IDCs appears helpful in predicting patient prognosis and preferential metastatic sites of the tumors.

Wohlbekannt sind pathische Geschehnisse im Interstitium des sog. Speicheldrusenmischtumors in Form schleimiger Verquellung mit und ohne Histolyse sowie in Form der Ablagerung chondrinoser Grundsubstanz. Weniger beachtet erscheint die Fibrosierung myxomatoser Geschwulsknoten und die Lieferung reichlicher argyrophiler Fasermasse mit nachtraglicher Hyalinisierung, anscheinend unbeachtet das Vorkommnis eines Balkenwerkes mit eigenartigen argyrophilen, PAS-positiven und fuchselinophilen Strukturen, und das Vorkommnis spinnenformiger und kringelformiger Figuren sowie klobiger Coacervate.

A mucoepidermoid tumor of the palate has been described. This tumor, which is of a low grade of malignancy, will probably cause no difficulty if it has been completely removed. If not removed entirely, it may tend to recur locally. These tumors, because of their variable behavior pattern, should be considered as being of either a low or high grade of malignancy.