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Breast-malignant, males, children
Myoepithelial carcinoma
Author: Nat Pernick, M.D, PathologyOutlines.com, Inc.
Reviewer: Daniel Visscher, M.D., University of Michigan Hospitals, February 2009 (see Reviewers page)
Revised: 15 September 2009
Last major update: September 2009
Copyright: (c) 2002-2009, PathologyOutlines.com, Inc.
Definition
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● Rare tumor composed solely of cytologically malignant myoepithelial cells with mitotic activity
Terminology
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● Also called malignant myoepithelioma
Epidemiology
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● Median age 60 years
Treatment and prognosis
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● Complete excision with negative margins
● 2 and 5 year survival is 88% and 55% (Eur J Surg Oncol 2004;30:357)
Case reports
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● 52 year old woman with infiltrating tumor (Diagn Pathol 2008 Feb 8;3:7)
● 70 year old woman (Br J Radiol 2005;78:444)
● Tumor arising in adenomyoepithelioma (Pathol Int 2006;56:211)
Gross description
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● Up to 21 cm, well defined with focal marginal irregularity, may be stellate
● Large tumors may have hemorrhage and necrosis
Microscopic description
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● Infiltrating spindle cells with fibrillar eosinophilic cytoplasm
● Tumor appears to arise from myoepithelial cells of ductules at periphery of lesion
● Cells have variable atypia
● Mitotic figures common, but may be less than 4/10 HPF
● May have clear cells (Tohoku J Exp Med 2003;200:103), due to glycogen (J Clin Pathol 1997;50:700)
● May have necrosis
Micro images
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Irregular dense proliferation Tumor cells invade normal Tumor infiltration of stroma
of pleomorphic spindle cells breast tissue
Myoepithelial carcinoma in Foci of epithelioid cells Spindled myoepithelial cells
adenomyoepithelioma with
spindle cell elements
Various images
S100+ p63+
Cytology description
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● Cohesive cell groups composed of spindle cells with atypical cigar-shaped nuclei
● Also epithelioid cells, mitotic figures
Cytology images
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Crowded haphazard cluster of Nest of pleomorphic cells is composed
cells in metachromatic stroma of large epithelioid, plasmacytoid and spindle cells
Positive stains
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Myoepithelial markers:
● Smooth muscle actin, S100, p63
● Also CD10, cytokeratin (pankeratin, CK5 and CK14), vimentin
Negative stains
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● ER, PR
Electron microscopy
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● Perinuclear tonofilaments, subplasmalemmal bundles of microfilaments with dense bodies, intermediate junctions, poorly developed desmosomes, pinocytic vesicles, fragmented external lamina (Int J Surg Pathol 2002;10:281)
Differential diagnosis
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● Spindle cell carcinoma - negative for myoepithelial markers
● Fibromatosis - no dominant nodule
● Myofibroblastic lesions - usually no dominant nodule, keratin negative
Additional references
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End of Breast – Malignant, Males, Children > Myoepithelial carcinoma
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