33 Special Types of Invasive Breast Carcinoma: Diagnostic Criteria ...

Because more than half of adenoid cystic carcinomas are infiltrative focally, the most
important therapeutic goal is complete tumor removal with uninvolved margins of
excision.
Pastolero et al. (27) have recently studied proliferative activity and p53 expression in
four cases of adenoid carcinoma of the breast. The pathologic features examined
included light microscopy; electron microscopy; immunohistochemistry using
antibodies to keratin, vimentin, S100 protein, actin, estrogen, and progesterone
receptors, and proliferation marker MiB-1, and p53 suppressor protein; image
cytometric analysis for measurement of DNA ploidy; and molecular analysis using
polymerase chain reaction single strand conformation polymorphism to assess point
mutation of the p53 gene. All of the cases had a low nuclear grade, were negative for
estrogen and progesterone receptors, and were DNA diploid. Three of the cases
showed no evidence of metastases and had
small primary tumors with low proliferative activity and absence of p53 protein
expression. In contrast, one of the cases showed axillary lymph node metastases and in
this case the primary tumor was large with a higher proliferative activity and
expression of p53 protein, suggesting that these factors might play a role in the
biological behavior of adenoid cystic carcinoma. These data suggest that detailed
molecular analysis may identify a group of aggressive adenoid cystic carcinomas. We
have recently studied adenoid cystic carcinomas of salivary glands and showed
relatively high MIB-1 staining and frequently strong expression of Bcl-2, the
apoptosis suppressor protein (28).
Some conventional, less favorable forms of mammary carcinoma may be incorrectly
diagnosed as adenoid cystic carcinoma (1, 2, 13); ~50% of the cases of adenoid cystic
breast carcinoma recorded by the Connecticut Tumor Registry were misclassified
(13). Most of the errors resulted from including invasive duct and even multifocal
intraductal carcinomas with a prominent cribriform component. Problems also occur
in distinguishing adenoid cystic from papillary and mucinous carcinomas.
Differential diagnosis: Although many varieties of cutaneous adnexal tumors can
arise in the skin and subcutis overlying the breast, some of these lesions deserve
special mention because of their propensity for occurring within the breast (29-40).
These are the infiltrating syringomatous adenoma of the nipple and mixed
salivary-type (pleomorphic) adenoma of the breast (29-38). Given the common
embryologic origin of the sweat, salivary, and mammary glands, finding similar
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