A rare case report of recurrent metastatic breast cancer mimicking primary pancreatic cancer.

Introduction: Secondary pancreatic tumors are rare, of which a breast cancer primary is extremely uncommon. To our knowledge, we present the 14th case reported worldwide and first from Singapore of lobular breast cancer metastasizing to the pancreas.
Presentation of Case: A 53-year-old woman presented with painless obstructive jaundice, weight loss over 1.5 months and a 2 cm right breast mass. She had left breast Invasive Lobular Carcinoma (ILC) treated 5 years prior with wide local excision, adjuvant radiotherapy and hormonal therapy. She had elevated bilirubin, liver enzymes and Cancer Antigen (CA) 19-9. Imaging found 3 right breast nodules, left axillary lymphadenopathy, biliary dilatation with an ampullary mass, and bone metastases. Breast nodule biopsies confirmed ILC but ampullary mass cytopathology was inconclusive. Frozen section of the mass during exploratory laparotomy showed metastatic ILC; a triple bypass surgery was done and chemo-endocrine therapy commenced.
Discussion: ILC is the commonest type of breast carcinoma in cases with pancreatic metastases, usually recurring after long disease-free intervals, and widely metastatic at presentation. Imaging characteristics help differentiate secondary from primary pancreatic tumors. Radiological features and history of an extra-pancreatic cancer suffice in suspecting pancreatic metastases. Despite limited surgical experience, it is well accepted that pancreatic metastasectomy offers reasonably good long-term survival rates, quality of life and can even be curative in highly selected cases.
Conclusion: This case is an interesting case because it highlights the diagnostic dilemma involved in the rare entity of breast cancer metastatic to the pancreas, and summarizes its diagnosis and management.
(Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)