Atypical Intestinal Metastases from Invasive Lobular Carcinoma of the Breast: Two Surgical Cases Mimicking Primary Gastrointestinal Tumors.

introductionGastrointestinal metastasis arising from invasive lobular carcinoma (ILC) of the breast is a rare but clinically significant manifestation. Unlike invasive ductal carcinoma, ILC has a higher propensity to metastasize into the gastrointestinal (GI) tract, often presenting with non-specific symptoms and mimicking primary GI tumors. Its accurate diagnosis requires a high index of suspicion and immunohistochemical (IHC) confirmation. Herein, we report 2 cases of intestinal metastases from ILC presenting with bowel stenosis. CASE PRESENTATION: Case 1 involved a 45-year-old woman with no known primary malignancy, who presented with duodenal and small bowel strictures. CT revealed narrowing of the small intestine, along with multiple sclerotic bone lesions. Surgical resection was performed, following which histopathological examination revealed ILC with a characteristic IHC profile (CK7

conclusionsThese cases demonstrate the diagnostic challenges posed by GI metastases arising from ILC, particularly due to submucosal infiltration and lack of endoscopic findings. IHC plays a critical role in differentiating these lesions from primary GI tumors. Although surgical resection may not prolong survival, it is valuable for symptomatic relief and for establishing a definitive diagnosis. Surgeons should be aware of the risk of ILC metastasizing into the GI tract. In patients presenting with atypical intestinal stenosis-particularly those with a history of ILC-metastasis should be considered. In such cases, IHC-guided diagnosis is essential.