Systemic Sarcoidosis Mimicking Metastatic Invasive Ductal Carcinoma of the Breast

Sarcoidosis is a granulomatous inflammatory disorder of uncertain etiology that can closely mimic metastatic malignancies, particularly when it presents with multi-organ involvement. In patients with a confirmed diagnosis of cancer, to avoid misdiagnosis and subsequent inappropriate treatment, distinguishing between sarcoidosis and metastatic disease is essential. Histologic confirmation through tissue sampling and correlation with tumor markers are critical tools in this process. We report a case of a 36-year-old female with invasive ductal carcinoma of the breast who presented with suspicious findings that indicated metastatic disease involving her lungs, liver, and bones. However, tumor marker levels and histopathology revealed systemic sarcoidosis, not metastatic spread.