1 March 2017 - Case of the Week #418

All cases are archived on our website. To view them sorted by case number, diagnosis or category, visit our main Case of the Week page. To subscribe or unsubscribe to Case of the Week or our other email lists, click here.

Thanks to Dr. Jatin S. Gandhi, Consultant at Rajiv Gandhi Cancer Institute and Research Centre, New Delhi (India) for contributing this case. To contribute a Case of the Week, follow the guidelines on our main Case of the Week page.




Advertisement


Website news:

(1) Reminder! We have a new contest to win a $100 Amazon gift card, which runs through 12 March 2017. We are looking for the best idea on how to increase Amazon.com sales through our website. As you may know, if you purchase anything from Amazon, after first going through a link on our website (in the Header, Footer, Books page or a Banner), Amazon pays us ~5% of the purchase price as an "affiliate partner". We use this money to support our website, and also distribute 10% of what we receive to a designated charity. Email NatPernick@gmail.com with your idea on how to get Pathologists to purchase from Amazon.com through our website more often.

(2) We have started posting submitted Pathology Humor on our Facebook and Newsletter pages once a month. Email your suggestions to Dr. Pernick at NatPernick@gmail.com.

(3) We have now posted the Jobs Report Summary for 2016, for jobs posted at PathologyOutlines.com. Click here to read the full report.

Visit and follow our Blog to see recent updates to the website.



Case of the Week #418

Clinical history:
A 68 year old woman presented with a breast mass, present for 14 years, but gradually increasing in size over the past 6 months. Clinical examination revealed a 10 cm mass with erythematous, indurated and shiny overlying skin and nipple retraction. Mammogram showed a lobulated breast measuring 8 x 7 cm, with no suspicious microcalcifications (BIRADS 4). FNA was positive for malignant cells. A modified radical mastectomy was performed, revealing a 6.5 x 5.0 cm grey white lobulated tumor with irregular borders, and yellow areas indicating necrosis. The overlying skin and nipple areola were grossly not involved by tumor.


Macro images:



Micro images:


Permission to use images courtesy of Indian J Pathol Microbiol 2011;54:230

What is your diagnosis?
































Diagnosis:
Malignant Adenomyoepithelioma
No regional nodal metastasis (pT3N0)


Special Stains:

CK7

34βE12

CD117

p63

Smooth muscle myosin heavy chain



Test question (answer at the end):
Which of the following statements is not true:

A. Adenomyoepithelioma of the breast is a biphasic tumor.
B. Adenomyoepithelioma typically has benign or low grade malignant behavior.
C. It is considered a variant of intraductal papilloma.
D. In malignant cases, only the epithelial component demonstrates malignant transformation.


Discussion:

Histology shows a biphasic tumor of malignant myoepithelial and epithelial cells with cytologic atypia, mitotic figures and necrosis. Immunostains were positive in the epithelium for CK7, 34βE12 and CK5 (not shown), and in the myoepithelium for p63, smooth muscle myosin heavy chain and S100 (not shown). ER and PR were negative (not shown).

Adenomyoepithelioma, first recognized in the breast in 1970 (Curr Top Pathol 1970;53:161), is an uncommon biphasic tumor with variable epithelial and myoepithelial components, usually with benign to low grade malignant behavior and a propensity for recurrence (Arch Pathol Lab Med 2013;137:725). Since papillary formations are common, it is considered a variant of intraductal papilloma (Hum Pathol 1987;18:1232). Although rare, either component can show malignant transformation, so thorough examination is required. Malignant lesions have areas of classic tumor with either obvious or subtle focal malignant features. Recurrence and metastases have been reported in both groups (World J Surg Oncol 2013;11:285). The epithelial component is typically cytokeratin+, EMA+ and CEA+; the myoepithelial component is S100+, SMA+, SMMHC+ and p63+.

Other lesions with prominent myoepithelial cells include myoepitheliosis (non-palpable, microscopic proliferation of myoepithelial cells in or around small ducts) and myoepithelial carcinoma (no epithelial component).

Treatment includes surgery and standard chemotherapy or radiation therapy regimens. In one case report, eribulin was been reported to be effective (J Breast Cancer 2015;18:400).

Test Question Answer:
D. In malignant cases, both the epithelial and myoepithelial component may demonstrate malignant transformation.

Discussion by Nat Pernick, M.D.