- Heterogeneous group of neoplasms with predominant component other than epithelial / glandular
- 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
- 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)
- 35 year old woman BRCA1 carrier (Breast Cancer 2011;18:137)
- 37 year old woman with giant cystic tumor (Acta Cytol 2006;50:327)
- 49 year old woman with metaplastic carcinoma of abdominal wall muscle (Breast Cancer 2012 Mar 2 [Epub ahead of print])
- 52 year old woman with CD117+ tumor (The Internet Journal of Pathology 2009;8:2)
- 52 year old woman with ductal, squamous and cartilaginous components in tumor (Mod Pathol 2001;14:1183)
- 57 year old woman with abscess (Int Semin Surg Oncol 2006;3:23)
- 66 year old woman with circumscribed mass (Case of the Week #6)
- 77 year old woman with extensive osseous differentiation (Breast 2008;17:314)
- Bilateral tumors, each clonal but different clones (Hum Pathol 2002;33:677)
- With melanocytic differentiation (Mod Pathol 1997;10:592)
- Mastectomy or local excision
- 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
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
- 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)
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
Images hosted on Flickr:
Squamous component
EGFR expression
Images hosted on other servers:
Various images
Case #294
Keratin+ cells
H&E, EGFR and EGFR-CISH
EGFR
EGFR and HER2 over expression in spindle cell carcinoma
Various images
- Moderate / high cellularity (68%), necrosis (47%), cells are sarcomatoid, poorly differentiated carcinoma or squamous carcinoma
- Dual components usually not identified (J Clin Pathol 2007;60:529)
- Also clusters of carcinoma cells (Diagn Cytopathol 2006;34:772)
Images hosted on other servers:
With myoepithelial and myxoid components
- Vimentin in mesenchymal elements
- Keratin (broad spectrum or 34betaE12) in spindle or epithelial cells
- EGFR (76%, Breast Cancer Res 2005;7:R1028)
- Squamous components are p63+
- Non-squamous tumors express smooth muscle actin and p63 (nuclear staining, Am J Surg Pathol 2004;28:1506)
- Chondroid cells are S100+
- Also laminin 5 (Am J Surg Pathol 2008;32:345), CD10, CD29 and 14-3-3-sigma (Am J Surg Pathol 2005;29:347)
- Variably positive for CK5 and CK14 (Hum Pathol 2003;34:1009)
- ER, PR, HER2 (Turk Patoloji Derg 2012;28:134) and mucin
- Often S100
- Mammaglobin (Am J Clin Pathol 2012;137:747)
- 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)
- Myoepithelial carcinoma: may have ducts with prominent myoepithelial cells at periphery, diffusely S100+
- Myofibroblastic tumors
- Phyllodes tumor
- Primary breast sarcoma: no epithelial elements or keratin+ elements
