BREAST METASTASIS OF RECTAL ADENOCARCINOMA

Case Presentation A 42-year-old woman presented with colicky abdominal pain, abdominal distension, and altered bowel habits, including constipation. During the investigation, she was diagnosed with high rectal adenocarcinoma, subocclusive, with a large, solitary hepatic metastasis. A 3 cm breast nodule was also diagnosed. Due to subocclusive symptoms, the patient underwent a rectosigmoidectomy, and histological analysis revealed a poorly differentiated adenocarcinoma with a mucinous component, pT4aN2a, with free margins and immunohistochemical studies showing no alterations in repair proteins. She started chemotherapy with 5-fluorouracil and oxaliplatin, when the breast nodule fistulized to the skin. A core biopsy was performed, suggesting triple-negative invasive ductal carcinoma. Chemotherapy was switched to carboplatin and paclitaxel, and the patient underwent mastectomy with regional lymphadenectomy. The histological study confirmed metastatic gastrointestinal carcinoma, with free margins and regional lymph node involvement. Eight months after the colorectal surgery, the patient developed local recurrence, increased hepatic metastasis, new breast metastasis, and suspected cutaneous metastasis. She is currently receiving palliative chemotherapy.

Discussion Breast metastasis from colorectal adenocarcinoma is extremely rare. Primary tumors most commonly associated with breast metastasis include contralateral breast cancer, leukemia, melanoma, lymphoma, ovarian cancer, lung cancer, and stomach cancer. The literature reports only 49 cases of colorectal metastasis on the breast, all with poor prognosis and, in some cases, difficult diagnosis. Since both breast and colorectal tumors are the most common neoplasms in the female population, the suspicion of a second primary tumor is inevitable. Treatment is challenging, as metastases often occur on multiple sites, indicating that the disease is systemic and progresses rapidly.

Conclusion Breast metastasis from colorectal adenocarcinoma is extremely rare. Diagnosis requires cooperation between the surgeon and pathologist to avoid unnecessary aggressive procedures and provide the best therapeutic approach.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
25 April 2025