Bilateral Breast Carcinoma
Bilaterality in Breast Cancer: Approximately 4% of women with newly diagnosed breast cancer are found to have contralateral breast carcinoma with magnetic resonance imaging (MRI). Patients with bilateral breast cancer have a greater frequency of multicentricity in one or both breasts as compared to women with unilateral breast cancer (19% vs 3%).
Family history: The incidence of positive family history in patients with bilateral and unilateral breast carcinomas is 40% and 28% respectively. The role of BRCA1 and BRCA2 mutations in bilaterality is discussed below. Even non-BRCA1/BRCA2 related familial breast cancers have a greater risk of bilaterality. The 20-year cumulative risk of contralateral breast carcinoma in this group is about 27% which is significantly higher than the background risk of about 5%.
BRCA1/BRCA2 Mutations: In women with germline mutations of BRCA1 gene, there is a greater risk of contralateral breast cancer. The cumulative risk is 50% by age 50 and 64% by 70 years. With BRCA2 mutations, the cumulative risk is 37% by age 50 and 52% by 70 years. Adjuvant tamoxifen therapy has been shown to reduce the risk of contralateral breast carcinoma in BRCA1/BRCA2 mutation carriers.
Many patients with ipsilateral breast carcinoma are now choosing to undergo prophylactic contralateral mastectomy to reduce their risk of contralateral tumors.
Case History: This 65 y/o female presented with 1-yr history of slowly enlarging lumps in both breasts. There was asymmetric enlargement of her breasts with nipple retraction and peau d'orange appearance as shown in this clinical photograph. Clinical examination revealed hard lumps in both breasts which were confirmed to be infiltrating ductal carcinoma on biopsies.
Case courtesy of: Dr. Sanjay D. Deshmukh, Professor of Pathology, Pad. Dr. V. Vikhepatil Medical College & Hospital, Ahmednagar, India.