LOCALLY ADVANCED SYNCHRONOUS BILATERAL BREAST CANCER: A RARE CASE REPORT

Abstract

Introduction: Synchronous bilateral breast cancer (SBBC) consists of the simultaneous presence of two primary tumors
at diagnosis. There is no consensus on its origin, and it may be a metastasis of a primary lesion or a second independent
tumor. The incidence of SBBC has been reported to be approximately 3%. The prognosis of SBBC was considered to be
reserved, which is why bilateral mastectomy is the preferred approach. Case report: A 44-year-old patient with no family
record of gynecological neoplasm sought care reporting bilateral breast pain and palpable nodular lesions on the breasts.
On examination, a hard nodule measuring 10×12 cm was palpated on the left breast (LB) associated with ulcerated areas
in the superior lateral quadrant. On the right breast (RB), a mobile nodule was palpable, measuring 8×8 cm with chocolate-
-colored nipple discharge. Clinically positive axillary lymph nodes are bilateral. She had a mammogram, which showed a
nodule with spiculated contours, measuring 2.5 cm in the SLQ of the LB, with apparent associated dermal retraction and
multiple, grouped microcalcifications on RB-BIRADS 5. She underwent core biopsy, which resulted in invasive lobular
carcinoma and dermal infiltration, with immunohistochemistry (IHC): positive PR and ER, positive HER2, Ki-67 positive
in 40% on LB, and carcinoma invasive ductal, non-special type, with IHC: negative RP and RE, HER2 score 3+, and Ki-67
positive in 60% on RB. She underwent neoadjuvant chemotherapy, followed by bilateral mastectomy with sentinel lymph
node biopsy. The anatomopathological (AP) study of the LB surgical specimens revealed residual ductal carcinoma in situ,
free margins, and neoplasm-free lymph nodes. The RB’s AP revealed high-grade (comedocarcinoma), intermediate-grade
residual intraductal carcinoma, alongside an extensive fibro hyalinized area of the stroma, foci of lobular cancerization,
absence of residual invasive component, free margins, and absence of lymph node metastasis. The patient underwent
adjuvant radiotherapy and hormone therapy with tamoxifen.