Splenic Rupture Due to Metastasis of Breast Cancer: A Report of a Rare Case and Focused Literature Review

The most common primary tumors that metastasize to the spleen include melanoma, lung, colorectal, ovarian, and breast cancers (BC). Nearly all patients with splenic metastases (SM) present with disseminated malignant disease rather than isolated involvement. We report the case of a 58-year-old female patient with BC who developed SM and subsequently died following splenic capsular rupture. The patient initially presented with biopsy-proven BC and underwent neoadjuvant therapy followed by right modified radical mastectomy. She later received adjuvant systemic therapy, radiotherapy, and tamoxifen. During follow-up, cervical lymph node metastasis was detected, and breast magnetic resonance imaging (MRI) revealed a new lesion in the contralateral breast, metastatic left axillary lymph nodes, and multiple pulmonary nodules. She subsequently underwent a left modified radical mastectomy. A few days after this second surgery, she presented to the emergency department with acute symptoms. Imaging demonstrated a hepatic metastasis, a SM, and active splenic bleeding. Emergency splenectomy was performed; however, the patient died during postoperative observation. Although SM from BC is exceedingly rare, clinicians should remain alert, particularly in patients exhibiting aggressive tumor biology or unfavorable histological subtypes. Splenic involvement may progress rapidly and can lead to life-threatening complications, including capsular rupture.