Home   Chapter Home   Jobs   Conferences   Fellowships   Books

 

 

Advertisement 

 

Breast-nonmalignant

Benign tumors / changes

Myoepithelioma of breast

 

Reviewer: Hind Nassar, M.D. in January 2009 (see Authors page)

Revised: 8 October 2012, last major update April 2010

Copyright: (c) 2002-2010, PathologyOutlines.com, Inc.

 

Definition

=========================================================================

● Bland spindle cell lesion with myoepithelial phenotype

 

Terminology

=========================================================================

Myoepitheliosis: multifocal, often microscopic proliferation of myoepithelial cells in or around small ducts; usually an incidental finding and not palpable (Am J Surg Pathol 1991;15:554)

● See also myoepithelial carcinoma in Breast-Malignant chapter

 

Epidemiology

=========================================================================

● Rare

 

Sites

=========================================================================

 

Etiology

=========================================================================

 

Clinical features

=========================================================================

● Usually benign, may recur locally

 

Prognostic factors

=========================================================================

 

Case reports

=========================================================================

● 71 year old woman with local recurrence (Tunis Med 2004;82:324)

● Renal dialysis patient with benign appearing tumor with metastatic behavior (ANZ J Surg 2004;74:1135)

 

Treatment

=========================================================================

 

Clinical images

=========================================================================

 

Gross description (Macroscopy)

=========================================================================

 

Gross images

=========================================================================

 

Micro description (Histopathology)

=========================================================================

● Dense spindle cell neoplasm, may be arranged in storiform pattern

● Tumor cells have eosinophilic cytoplasm, oval and regular nuclei

● May have polygonal cells with clear cytoplasm and hyperchromatic nuclei

● May infiltrate fat or surround normal ducts

● No mitotic figures, no necrosis, no atypia

 

Micro images

=========================================================================

 

                                                               

Invasive dense                    Plump interlacing spindle                Occasional polygonal cells

spindle cell lesion              cells with ovoid nuclei                       with hyperchromatic nuclei

 

 

               

Broad fascicles     Resembles leiomyoma                                 

 

 

                               

Actin+ spindle cells with                  Muscle specific actin+

positive internal control

in normal duct at top

 

Virtual Slides

=========================================================================

 

Videos

=========================================================================

 

Cytology description

=========================================================================

● Epithelial and spindled cells

● Mild to moderate nuclear pleomorphism, occasional intranuclear cytoplasmic vacuoles, naked bipolar cells, metachromatic myxoid or fibrillary material

● No necrosis, no mitotic figures

 

Cytology images

=========================================================================

 

Positive stains

=========================================================================

● Myoepithelial cell phenotype: keratin, EMA, alpha smooth muscle actin, calponin, caldesmon, vimentin, CD10, p63, S100

 

Negative stains

=========================================================================

● Low molecular weight keratin CK8/18 (CAM5.2), desmin, CD34, ER, PR

 

Electron microscopy descriptions

=========================================================================

● Activated, differentiated myoepithelial cells (cytoplasmic bundles of myofilaments, desmosomes and basal lamina), variable squamous metaplasia (Am J Surg Pathol 1982;6:785)

 

Electron microscopy images

=========================================================================

 

Molecular / cytogenetics description

=========================================================================

 

Molecular / cytogenetics images

=========================================================================

 

 

Differential Diagnosis

=========================================================================

Adenomyoepithelioma: also epithelial cells  

Metaplastic carcinoma: has malignant component

Myoepithelial carcinoma: has malignant cells and mitotic activity

Myofibroblastoma: lacks epithelial phenotype (keratin-, S100-)

 

Additional references

=========================================================================

Stanford University

 

End of Breast-nonmalignant > Benign tumors / changes > Myoepithelioma

 

 

This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must also be interpreted in the context of a patient's clinical data using reasonable medical judgment.  This website should not be used as a substitute for the advice of a licensed physician.

 

All information on this website is protected by copyright of PathologyOutlines.com, Inc.  Information from third parties may also be protected by copyright.  Please contact us at copyrightPathOut@gmail.com with any questions (click here for other contact information)..