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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/01/08 21:03:38」(JST)

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Myoepithelial cells (sometimes referred to as myoepithelium) are cells usually found in glandular epithelium as a thin layer above the basement membrane but generally beneath the luminal cells. These may be positive for alpha smooth muscle actin and can contract and expel the secretions of exocrine glands. They are found in the sweat glands, mammary glands, lacrimal glands, and salivary glands. Myoepithelial cells in these cases constitute the basal cell layer of an epithelium that harbors the epithelial progenitor. In the case of wound healing, myoepithelial cells reactively proliferate. Presence of myoepithelial cells in a hyperplastic tissue proves the benignity of the gland and, when absent, indicates cancer. Only rare cancers like adenoid cystic carcinomas contains myoepithelial cells as one of the malignant components.

It can be found in endoderm or ectoderm.^[1]

Markers

Myoepithelial cells are true epithelial cells positive for keratins, not to be confused with myofibroblasts which are true mesenchymal cells positive for vimentin. These cells are generally positive for alpha smooth muscle actin (αSMA), cytokeratin 5/6 and other high molecular weight cytokeratins, p63 and caldesmon. Myoepithelial cells are stellate in shape and are also known as basket cells. They lie between the basement membrane and glandular epithelium. Each cell consists of a cell body from which 4-8 processes radiate and embrace the secretory unit. Myoepithelial cells have contractile functions. They help in expelling secretions from the lumen of secretory units and facilitate the movement of saliva in salivary ducts.

References

^ Jules J. Berman (2009). Neoplasms: principles of development and diversity. Jones & Bartlett Learning. pp. 207–. ISBN 978-0-7637-5570-6. Retrieved 16 April 2010.

External links

Myoepithelium at eMedicine Dictionary

Anatomy Atlases - Microscopic Anatomy, plate 07.141 - "Axillary Sweat Gland: Myoepithelium"
Histology image: 43_13 at the University of Oklahoma Health Sciences Center - "thick skin"
Histology at KUMC glands-glands09 "Simple Tubular Coiled"
Physiology at MCG 6/6ch4/s6ch4_4

This anatomy article is a stub. You can help Wikipedia by expanding it.

UpToDate Contents

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1. 乳汁分泌の生理学 physiology of lactation
2. 頭頸部腫瘍の病理 pathology of head and neck neoplasms
3. 黒色腫（メラノーマ）における所属リンパ節の病理学的評価 pathologic evaluation of regional lymph nodes in melanoma
4. 悪性唾液腺腫瘍：再発性および転移性疾患の治療 malignant salivary gland tumors treatment of recurrent and metastatic disease
5. 妊娠に対する母体の内分泌系および代謝の適応 maternal endocrine and metabolic adaptation to pregnancy

English Journal

Consistent SMARCB1 homozygous deletions in epithelioid sarcoma and in a subset of myoepithelial carcinomas can be reliably detected by FISH in archival material.

Le Loarer F1, Zhang L, Fletcher CD, Ribeiro A, Singer S, Italiano A, Neuville A, Houlier A, Chibon F, Coindre JM, Antonescu CR.Author information 1Pathology Department, Memorial Sloan-Kettering Cancer Center, New York, NY; Pathology Department, Institut Bergonié Cancer Center, Bordeaux, France.AbstractEpithelioid sarcomas (ES) are mesenchymal neoplasms subclassified into distal and proximal subtypes based on their distinct clinical presentations and histologic features. Consistent loss of SMARCB1 nuclear expression has been considered as the hallmark abnormality for both subtypes, a feature shared with atypical teratoid/rhabdoid tumor of infancy (ATRT). While virtually all ATRTs harbor underlying SMARCB1 somatic or germline alterations, mechanisms of SMARCB1 inactivation in ES are less well defined. To further define mechanisms of SMARCB1 inactivation a detailed molecular analysis was performed on 40 ES (25 proximal and 15 distal ES, with classic morphology and negative SMARCB1 expression) for their genomic status of SMARCB1 and related genes encoding the SWI/SNF subunits (PBRM1, BRG1, BRM, SMARCC1/2 and ARID1A) by FISH using custom BAC probes. An additional control group was included spanning a variety of 41 soft tissue neoplasms with either rhabdoid/epithelioid features or selected histotypes previously shown to lack SMARCB1 by IHC. Furthermore, 12 ES were studied by array CGH (aCGH) and an independent TMA containing 50 additional ES cases was screened for Aurora Kinase A (AURKA) and cyclin D1 immunoexpression. Homozygous SMARCB1 deletions were found by FISH in 36/40 ES (21/25 proximal-type). One of the distal-type ES displayed homozygous SMARCB1 deletion in the tumor cells, along with a heterozygous deletion within normal tissue, finding confirmed by array CGH. None of the proximal ES lacking homozygous SMARCB1 deletions displayed alterations in other SWI/SNF subunits gene members. Among controls, only the SMARCB1-immunonegative myoepithelial carcinomas displayed SMARCB1 homozygous deletions in 3/5 cases, while no gene specific abnormalities were seen among all other histologic subtypes of sarcomas tested regardless of the SMARCB1 protein status. There was no consistent pattern of AURKA and Cyclin D1 expression. The array CGH was successful in 9/12 ES, confirming the SMARCB1 and other SWI/SNF genes copy numbers detected by FISH. Our study confirms the shared pathogenesis of proximal and distal ES, showing consistent SMARCB1 homozygous deletions. Additionally we report the first ES case associated with a SMARCB1 constitutional deletion, establishing a previously undocumented link with ATRT. Alternative mechanisms of SMARCB1 inactivation in SMARCB1-disomic ES remain to be identified, but appear unrelated to large genomic abnormalities in other SWI/SNF subunits. © 2014 Wiley Periodicals, Inc.
Genes, chromosomes & cancer.Genes Chromosomes Cancer.2014 Jun;53(6):475-86. doi: 10.1002/gcc.22159. Epub 2014 Mar 3.
Epithelioid sarcomas (ES) are mesenchymal neoplasms subclassified into distal and proximal subtypes based on their distinct clinical presentations and histologic features. Consistent loss of SMARCB1 nuclear expression has been considered as the hallmark abnormality for both subtypes, a feature share
PMID 24585572

Bilateral syringomatous adenomas of the nipple: case report with immunohistochemical characterization of a rare tumor mimicking malignancy.

Montgomery ND1, Bianchi GD, Klauber-Demore N, Budwit DA.Author information 1Dept of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, CB #7525, Brinkhous-Bullitt Bldg, Chapel Hill, NC 27599-7525; debra_budwit@med.unc.edu.AbstractObjectives Syringomatous adenoma of the nipple (SAN) is a rare benign infiltrative neoplasm that may be confused with low-grade breast carcinomas. We report the case of 71-year-old woman with a fungating left breast mass and subareolar calcifications in the contralateral breast. Methods Histomorphologic features were evaluated with standard H&E-stained sections. Both lesions were also evaluated by immunohistochemistry for further characterization. A literature review was performed to place the current case in context relative to previous observations. Results Both lesions were infiltrating syringomatous adenomas, confirmed by detailed immunohistochemical analyses, which also provided new evidence for the putative sweat duct origin for these tumors. The debated presence of myoepithelial cells in these lesions was newly and convincingly supported in this study by strong diffuse immunostaining of the outer cell layer of the tubules for smooth muscle myosin, cytokeratin 34bE12, cytokeratin 5/6, and p63. Previous reports describing similar detailed immunophenotypical characterization of these uncommon tumors are lacking. Conclusions To our knowledge, this case represents only the second reported patient with bilateral SAN and the first such case to be reported in the pathology literature.
American journal of clinical pathology.Am J Clin Pathol.2014 May;141(5):727-31. doi: 10.1309/AJCPFJUZTLL0VGNX.
Objectives Syringomatous adenoma of the nipple (SAN) is a rare benign infiltrative neoplasm that may be confused with low-grade breast carcinomas. We report the case of 71-year-old woman with a fungating left breast mass and subareolar calcifications in the contralateral breast. Methods Histomorphol
PMID 24713747

Tubular variant of basal cell adenoma shares immunophenotypical features with normal intercalated ducts and is closely related to intercalated duct lesions of salivary gland.

Montalli VA1, Martinez E, Tincani A, Martins A, do Carmo Abreu M, Neves C, Costa AF, de Araújo VC, Altemani A.Author information 1Department of Pathology, University of Campinas, (UNICAMP), Campinas, Brazil.AbstractAIMS: The morphological criteria for identification of intercalated duct lesions (IDLs) of salivary glands have been defined recently. It has been hypothesised that IDL could be a precursor of basal cell adenoma (BCA). BCAs show a variety of histological patterns, and the tubular variant is the one that presents the strongest resemblance with IDLs. The aim of this study was to analyse the morphological and immunohistochemical profiles of IDLs and BCAs classified into tubular and non-tubular subtypes, to determine whether or not IDL and tubular BCA represent distinct entities.
Histopathology.Histopathology.2014 May;64(6):880-9. doi: 10.1111/his.12339. Epub 2014 Feb 5.
AIMS: The morphological criteria for identification of intercalated duct lesions (IDLs) of salivary glands have been defined recently. It has been hypothesised that IDL could be a precursor of basal cell adenoma (BCA). BCAs show a variety of histological patterns, and the tubular variant is the one
PMID 24299520