Context: Much has been written about the clinical management and prognosis of breast carcinomas presenting during pregnancy and lactation, yet little is known about the detailed histopathology of these tumors.
Objective: To determine whether these carcinomas have any specific diagnostic features.
Design: A detailed histologic and immunohistochemical study of 14 cases of breast carcinoma presenting during or shortly after pregnancy or lactation was conducted. The findings were compared with a control group of 13 tumors developing in age-matched women with no recent history of pregnancy or lactation.
Setting: The histopathology department of a tertiary referral teaching hospital.
Results: Tumors in the pregnancy/lactation group had a significantly higher incidence of cancerization of lobules (79% vs 15%) and of grade III invasive ductal carcinomas (80% vs 33%). Tumors occurring during lactation were either totally or partly mucinous and were MUC2 positive. Tumors occurring during pregnancy, but not during lactation, were mostly estrogen and progesterone receptor negative (4/5 and 5/5, respectively). All tumors occurring during pregnancy and lactation that were tested for c-erbB-2 overexpression were negative, whereas all 4 tumors tested that occurred shortly after delivery or cessation of lactation were positive for c-erbB-2 overexpression. The incidence of axillary lymph node metastasis was high in both the study and control groups, although it was slightly higher in the control group (78% and 90%, respectively).
Conclusions: Although breast carcinomas diagnosed during or shortly after pregnancy and lactation have features in common with those developing in women of similar ages, particularly with respect to a high incidence of lymph node metastasis, the findings of this study suggest that they may also have distinct morphologic and immunohistochemical features of their own. Such features may vary according to whether the patient was pregnant, lactating, or had recently terminated her pregnancy or lactation at the time of surgical excision. Examination of more cases would help confirm these findings.