with a malignant transformation is extremely rare and when seen, is found in both ductal epithelial and MEP components.
This tumor's differential diagnoses include adenomyoepithelioma
, phyllodes tumor, adenoleiomyoma, fibroadenoma with prominent smooth muscle, fibromatosis, benign spindle cell tumor of the breast, fibrous histiocytoma, myoid hamartoma, myoepithelioma, fibromato-sis-like low-grade metaplastic carcinoma and leiomyosarcoma of the breast (9).
Its benign counterpart adenomyoepithelioma
is also a rare tumor of the breast reported for the first time in 1970 (2).
Hemotoxylin-eosin, S100, and MA903 histologic stains identified myoepithelial nuclear and cytoplasmic elements consistent with adenomyoepithelioma
Chemically induced mammary adenomyoepithelioma
and myoepithelial tumours.
This feature raises the differential diagnosis of the papillary variant of adenomyoepithelioma
of the breast associated with low-grade adenosquamous and sarcomatoid carcinomas.
Other differential diagnoses in terms of the histopathologic features of MCB include myoepithelial carcinoma of the breast, myofibroblastic tumors, phyllodes tumors, primary breast sarcoma, nodular fasciitis, fibromatosis, pleomorphic adenoma, and adenomyoepithelioma
Heterologous elements such as bone formation can be seen in the breast in hamartomas, calcified fibroadenoma, and osseous metaplasia in benign mesenchymal lesions such as lipoma or leiomyoma and in malignant lesions such as phyllodes tumor, metaplastic spindle cell carcinoma, matrix-producing carcinoma, sarcomas, and malignant adenomyoepithelioma
with osteogenic differentiation.
(AME), a biphasic neoplastic proliferation of luminal and myoepithelial cells, was first described by Hamperl (1) in 1970.
Biphasic lesions with a predominant spindle cell component and a benign epithelial (ductal) component, such as fibroadenomas, phyllodes tumors, pseudoangiomatous stromal hyperplasia, and adenomyoepithelioma
A number of breast tumors manifest true myoepithelial differentiation, including adenomyoepithelioma
and myoepithelioma, as well as the salivary glandlike tumors such as adenoid cystic carcinoma.