Breast Carcinoma with Choriocarcinomatous Features: A Case Report
A 56-year-old woman presented with a palpable mass in the upper outer quadrant of the right breast. She had no previous history of hydatidiform moles or choriocarcinoma. Following the first radiological studies that included mammography and ultrasonography (), she was referred for staging using F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). This scan showed a soft tissue mass with low accumulation of FDG with a maximum standardized uptake value (maxSUV) of 1.98 in the right breast (). No other hypermetabolic lesion was detected in the body. Clinically, the F-18 FDG PET/CT scan revealed malignancy in the right breast. The patient underwent a right mastectomy and a biopsy of sentinel nodes. The resected tumor was 2.4 cm in diameter with relatively well-defined irregular margins (). The cut surface was partially hemorrhagic and mostly gray to whitish-in color. Microscopically, the tumor was a typical high-grade invasive ductal carcinoma with multiple foci of choriocarcinomatous features without any other metaplastic squamous or spindle cell components (). The choriocarcinomatous lesion contained highly pleomorphic tumor cells with an increased nucleus-cytoplasmic ratio, prominent nucleoli, and syncytiotrophoblast-like multinucleated giant cells. The area of choriocarcinomatous differentiation comprised approximaterly 25% of the entire invasive carcinoma. Immunohistochemically, only the choriocarcinoma-resembling tumor cells were reactive for the hCG antibody (), but negative for HER2/neu, estrogen receptor (ER), and progesterone receptor (PR). Fifty percent of the tumor cells were reactive for the Ki-67 antibody. A diagnosis of BCCF was confirmed based on IHC and histological phenotype results. The postoperative serum β-hCG level (3.18 mIU/mL) was not increased significantly, while the 4 sentinel nodes showed no metastatic deposits.