Interventional management of chest wall sarcomatoid carcinoma mimicking breast cancer metastasis: A case report

Rationale: Breast cancer patients have an increased risk of developing second primary malignancies, with lung cancer accounting for approximately 5% of cases. Differentiating between metastatic disease and a second primary malignancy remains a diagnostic challenge. Patient concerns: A 45-year-old woman with a history of triple-negative breast cancer presented with a newly detected chest wall nodule during routine follow-up. Diagnoses: Contrast-enhanced imaging suggested metastatic disease. However, biopsy and immunohistochemistry confirmed a second primary lesion, consistent with either pulmonary sarcomatoid carcinoma or chest wall sarcoma. Interventions: The patient underwent a multimodal interventional regimen, including transarterial embolization followed immediately by radiofrequency ablation. Outcomes: At 1 month post-treatment, follow-up imaging demonstrated significant tumor shrinkage with no evidence of local recurrence. Lessons: This case underscores the importance of comprehensive diagnostic evaluation to distinguish metastatic disease from second primary malignancies in breast cancer patients. It also highlights the potential of interventional therapy as a minimally invasive treatment option for inoperable tumors, with multidisciplinary management being essential to optimize outcomes and prognosis.