5 May 2005 – Case of the Week #6

 

This is our sixth Case of the Week.  These cases can also be accessed by clicking on the Case of the Week button on the left hand side of our Home Page.  This email is only sent to those who requested to be on this list in writing or by email.  To view the images or references, you must click on the links in blue.

 

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This case is sponsored by Daedalus Software, Inc., the Biosample Repository Automation Company, which is a bioinformatics and software company headquartered in Cambridge, MA.  Daedalus Software, Inc. has 14 unique products which all cater to bioinformatics applications, biosample repository automation for diagnostic research, drug development, as well as tissue and organ for transplant.  Daedalus Software has employees located at four offices in the U.S.A. and internationally.  The company also custom-designs and co-develops new products with collaborators in the life science and healthcare industry segments.  Daedalus operates with a fundamental philosophy of focusing on client service and product quality.  Contact Info@DaedalusSoftware.com or 617-520-6604 x 4406 for more information.

 

This case was contributed by Dr. Inès Raoelfils, Centre Jean Perrin, Clermont-Ferrand, France.  We invite you to contribute a Case of the Week by sending microscopic images in JPG or GIF format, with a clinical history and any other images (gross, immunostains, EM, etc.) that may be helpful to NPernick@PathologyOutlines.com.  We have many breast cases for future use, but need cases of GI, GU and Gynecologic pathology. 

 

 

Case of the Week #6

 

A 66 year old woman had a well circumscribed breast mass and underwent needle biopsy.


Micro images:  low power; high power; CK7; S100

 

Additional immunostains: ER and PR negative

 

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Diagnosis:  metaplastic carcinoma of the breast

Discussion

Metaplastic carcinoma of the breast is a rare tumor in which the predominant component is not epithelial or glandular.  It is also called sarcomatoid carcinoma, carcinosarcoma or spindle cell carcinoma.  Distinction from invasive ductal carcinoma NOS is important because patients have shorter disease free survival, and metastases tend to be hematogenous, not nodal.  Metaplastic carcinoma has been classified into three categories – (a) carcinoma with an abundant matrix but without a spindle cell component, (b) spindle cell carcinoma with a lesser amount of carcinoma, and (c) a biphasic pattern of malignant glandular and spindle elements (carcinosarcoma).  The name “metaplastic” is due to the transformation of epithelial component into a nonglandular component, such as spindle cells, squamous cells or heterologous elements. 

 

Morphologically, the sarcomatous component may resemble low grade fibromatosis, or high grade fibrosarcoma, malignant fibrous histiocytoma, chondrosarcoma, osteosarcoma, rhabdomyosarcoma, angiosarcoma or a combination.  The epithelial component may be glandular or squamous.

 

Immunohistochemical stains are notable for keratin staining of the spindle cells.  A broad spectrum keratin cocktail or high molecular weight cytokeratin (34 beta E12) is recommended, and is usually positive.  Other keratin antibodies are less sensitive, as is S100.  A recent report concluded that p63, with strong, diffuse nuclear staining, is a good marker to distinguish spindle cell metaplastic carcinomas from other mesenchymal neoplasms, with 87% sensitivity and 99% specificity (AJSP 2004;28:1506).  The tumor in this case was not tested for p63.  Most metaplastic carcinomas are negative for ER and PR (as in this case), and negative for HER2 overexpression.  The epithelial and sarcomatoid components are derived from the same clone in most cases analyzed.

 

The differential diagnosis includes phyllodes tumor, nodular fasciitis, myofibroblastic tumor or primary breast sarcoma.  A fibromatosis-like variant of metaplastic carcinoma has also  been described (AJSP 2001;25:1009)

 

 

Nat Pernick, M.D.
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