Invasive lobular breast carcinoma with diffuse gastrointestinal metastases: a visual diagnostic pitfall.

Area of Science:

• Oncology
• Gastroenterology
• Pathology

Background:

• Invasive lobular carcinoma (ILC) of the breast is characterized by an infiltrative growth pattern.
• ILC has a propensity for gastrointestinal (GI) metastasis, often presenting without discrete masses.
• Metastatic ILC to the GI tract can mimic other conditions, leading to diagnostic challenges.

Purpose of the Study:

• To report a case of extensive GI involvement by ILC.
• To highlight the diagnostic difficulties associated with ILC metastasis to the GI tract.
• To emphasize the importance of considering ILC metastasis in patients with unexplained GI symptoms.

Main Methods:

• Case report of a 64-year-old woman with a history of ILC.
• Clinical presentation of progressive nausea, vomiting, and diarrhea.
• Diagnostic workup including computed tomography (CT), upper endoscopy, colonoscopy, and histopathological evaluation with immunohistochemistry.

Main Results:

• Surveillance imaging initially showed no metastatic disease.
• CT revealed nonspecific findings despite extensive mucosal involvement.
• Endoscopy demonstrated diffuse nodular and congested mucosa in the duodenum and colon.
• Histology confirmed poorly cohesive tumor cells consistent with metastatic breast carcinoma.

Conclusions:

• Diffuse GI involvement by ILC is an uncommon presentation.
• Metastatic ILC can mimic inflammatory, infectious, ischemic, or medication-related GI conditions.
• Early consideration of metastatic ILC is crucial for timely diagnosis and management, even with negative radiographic findings.