Metastatic lobular breast cancer to gynecologic sites: disease-free after surgery and chemotherapy

What happened, in summary

This 54-year-old woman had a prior history of lobular breast cancer classified as T2N1M0. In March 2005, she underwent left superior quadrantectomy with axillary lymphadenectomy, followed by adjuvant chemotherapy, radiotherapy, and hormonal treatment planned for 5 years. During regular follow-up, she developed painless vaginal bleeding in February 2008 while still receiving hormonal therapy. Pelvic examination found a 4 cm solid lesion in the left upper third of the vagina, extending through the vaginal wall and into the obturator fossa. The cervix was not involved, ultrasound did not show endometrial or adnexal abnormalities, and hysteroscopy with endometrial biopsy was negative. Tumor markers were normal. PET/CT showed isolated uptake in the left vaginal wall, and biopsy confirmed metastatic breast cancer. She underwent modified vaginectomy with complete resection of the mass and surrounding lympho-fatty tissue. Pathology showed metastatic poorly differentiated lobular breast cancer. Immunohistochemistry matched the primary tumor: estrogen receptor expression in 90% of tumor cells, no progesterone receptor expression, and negative C-Erb-B2/HER2 expression. Margins were negative. She then received pegylated liposomal doxorubicin at 40 mg/m² for 6 courses. After 14 months of negative follow-up, the team performed prophylactic completion surgery with total hysterectomy and bilateral salpingo-oophorectomy. Unexpectedly, microscopic metastases from lobular breast cancer were found in both the uterus and ovaries. No further adjuvant therapy was proposed. Twelve months later, she remained free from disease. The case also reflects a known behavior of lobular breast cancer: it can recur in unusual gynecologic sites and may remain clinically subtle, presenting here as painless bleeding despite normal tumor markers and otherwise good condition.