Criteria for medullary carcinoma - all of the following:
(1) syncytial growth pattern in > 75% of the tumor area
(2) margin completely circumscribed and pushing (noninfiltrative)
(3) moderate to marked mononuclear cell infiltrate of the tumor
(4) nuclei Grade 2 or 3 (moderate to severe pleomorphism)
(5) absence of intraductal growth
(6) absence of microglandular differentiation
where:
• Syncytial growth pattern consists of broad, interanastomosing sheets of tumor cells with indistinct cell borders.
Atypical medullary carcinomas were diagnosed with both of the following:
(1) syncytial growth pattern in > 75% of the tumor area
(2) 1 or 2 of the following:
(2a) infiltrative margins
(2b) sparse or only peripheral mononuclear cell infiltrate
(2c) Grade 1 nuclei (mild pleomorphism)
(2d) presence of microglandular differentiation
(2e) intraductal carcinoma
Nonmedullary carcinoma was diagnosed with one or both of the following:
(1) syncytial growth <= 75% of the tumor area
(2) 3 or more of the features listed for atypical medullary carcinomas
Jensen et al found that medullary carcinoma was associated with an excellent prognosis, while atypical or nonmedullary carcinomas had similar outcomes.
