Incidental gallbladder lymph node metastasis from invasive ductal carcinoma

Breast cancer metastasis to the gallbladder or its lymphatic drainage is exceedingly rare. We report a woman in her 70s with a remote history of invasive ductal breast carcinoma who underwent elective laparoscopic cholecystectomy for symptomatic cholelithiasis. Histopathology demonstrated chronic cholecystitis and, unexpectedly, metastatic adenocarcinoma within the cystic lymph node of Lund, without involvement of the gallbladder wall or mucosa. Immunohistochemistry showed ER, PR, GATA3, and CK7 positivity with HER2 and CK20 negativity, supporting breast origin and concordance with her previous carcinoma. Subsequent staging identified axillary nodal recurrence without initial visceral or osseous metastases. Endocrine therapy with anastrozole was commenced following multidisciplinary discussion. The patient subsequently developed progressive visceral metastatic disease and died under palliative care. This case highlights the importance of histopathological assessment of cholecystectomy specimens and awareness of atypical metastatic patterns in patients with previous malignancy.