Pancreatic metastasis from invasive pleomorphic lobular carcinoma of the breast: a rare case report

BACKGROUND Invasive pleomorphic lobular carcinoma (PLC) is an aggressive subtype of invasive lobular carcinoma of the breast, which has its own histopathological and biological features. The metastatic patterns for PLC are distinct from those of invasive ductal carcinoma. In addition, pancreatic metastasis from PLC is extremely rare. CASE PRESENTATION We report a rare case of a 48-year-old woman presenting with clinical gastrointestinal symptoms and pancreatic metastasis of PLC. The pancreatic tumor was composed of pleomorphic tumor cells arranged in the form of solid sheets and nests and as single files, with frequent mitotic figures, nucleolar prominence, high nuclear to cytoplasmic ratio and loss of cohesion. The malignant cells were positive for p120 (cytoplasmic) and GATA3 and negative for estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, E-cadherin, gross cystic disease fluid protein 15 and mammaglobin, which indicated a lobular carcinoma phenotype of the breast. CONCLUSIONS To the best of our knowledge, this is one of the few reported cases in the literature of pancreatic metastasis of invasive lobular carcinoma of the breast, of which the definitive diagnosis was obtained only after surgery. Rare metastasis sites should be considered, particularly, when a patient has a medical history of PLC.