Breast malignant, males, children
Carcinoma subtypes
Metaplastic carcinoma - general

Author: Monika Roychowdhury, M.D. (see Authors page)

Revised: 28 October 2016, last major update September 2012

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Metaplastic carcinoma [title] breast

Cite this page: Metaplastic carcinoma - general. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/breastmalignantmetaplastic.html. Accessed December 4th, 2016.
Definition / General
  • Heterogeneous group of neoplasms with predominant component other than epithelial / glandular
Terminology
  • Also called carcinosarcoma (if mesenchymal component is malignant), carcinoma with osteoclastic giant cells and carcinoma with osseous metaplasia
  • "Metaplastic" due to the transformation of epithelial component into a non-glandular component, such as spindle cells, squamous cells or heterologous elements
Clinical Features
  • Uncommon (< 5% of breast carcinomas)
  • More aggressive than invasive ductal NOS due to larger tumor size, higher grade
  • Metastases tend to be hematogenous and not nodal (Ann Surg Oncol 2007;14:166, Breast Cancer Res Treat 2007;101:349)
  • Represents a type of basal-like carcinoma lacking epidermal growth factor receptor and KIT activating mutations, but exhibiting high epidermal growth factor receptor copy number, primarily via aneusomy (Mol Cancer Ther 2008;7:944)
Case Reports
Treatment
  • Mastectomy or local excision
Gross Description
  • Well-circumscribed
  • Median 3 - 4 cm, range 1 - 21 cm
  • Usually firm, nodular
  • Squamous or chondroid areas are pearly white to gray glistening areas on cut surface
Gross Images

Images hosted on PathOut server:

Bisected squamous tumor (arrows at tumor margin)

Carcinoma with osteoclast-like giant cells



Images hosted on other servers:

Causing skin ulceration

Sharply circumscribed tumor

Micro Description
  • Sarcomatous component resembles fibromatosis (see variant), fibrosarcoma, malignant fibrous histiocytoma, chondrosarcoma or osteosarcoma (see variant), rhabdomyosarcoma, spindle cells (see variant), angiosarcoma or combination
  • May need to look carefully for epithelial component (may be ductal carcinoma in situ or invasive ductal carcinoma), may have osteoclast-like giant cells (Hum Pathol 1990;21:142)
  • Some classify as "with squamous metaplasia" or "with heterologous metaplasia"
  • Recommended to test any keratin negative stromal tumor of the breast with myoepithelial markers before calling it a primary sarcoma (Am J Surg Pathol 2005;29:347)
Micro Images

Images hosted on PathOut server:

Case of the Week #6



AFIP images

Well differentiated
epidermoid
carcinoma and
poorly differentiated
adenocarcinoma
merge with the
spindle cell component

Adenocarcinoma
with a tubular pattern
in the metaplastic
spindle cell component

Carcinomatous
glands are surrounded
by an undifferentiated
round cell proliferation
that merges with the
spindle cells

Transition from
adenocarcinoma to
spindle cell pattern



Poorly differentiated
carcinoma with traces
of squamous metaplasia
giving rise to the spindle
cell component

Invasive adenocarcinoma
at upper right, but most
tumor is solid
pseudosarcomatous
metaplastic elements with
pale, serpiginous areas
of necrosis

Adenocarcinoma with
transition to undifferentiated
carcinoma, an intermediate
step in conversion to
spindle cell metaplasia

Recurrent metaplastic
carcinoma 4 years after
mastectomy, tumor was
initially interpreted as a
radiation induced sarcoma



Resembles giant cell tumor of bone due to osteoclast-like giant cells

Osteoclast-like giant
cells in stroma associated
with the carcinoma component



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Squamous component

EGFR expression



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Various images

Case #294



Keratin+ cells

H&E, EGFR and EGFR-CISH

EGFR

EGFR and HER2 over expression in spindle cell carcinoma

Various images

Cytology Description
Virtual Slides

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With myoepithelial and myxoid components

Positive Stains
Molecular / Cytogenetics Description
  • Epithelial and sarcoma components originate from same clone
  • Epidermal growth factor receptor overexpression in 2/3, 1/3 of these have EGFR gene amplification, but no activating EGFR mutations (J Pathol 2006;209:445)
Differential Diagnosis