Supplementary Material for: Sister Mary Joseph’s Nodule Presenting with an Ulcerated Umbilicus as an External Diagnostic Clue Revealing a Deeply Situated Pancreatic Tail Cancer

Case Presentation: An 84-year-old female patient presented with umbilical hemorrhage. A central depressed lesion with reddish and multinodular change was exhibited in the umbilicus, showing with an ulcerated, infiltrative appearance. The patient was strongly suspected of having Sister Mary Joseph’s nodule (SMJN). Referring to the tertiary care hospital, laboratory tests revealed an elevated CA19-9 level of 15,366 U/mL, and a computed tomography scan showed a pancreatic tail tumor and the umbilical mass. Biopsy of the umbilical lesion revealed adenocarcinoma cells infiltrated in the skin, with immunohistochemical staining positive for CK7 and CA19-9 but negative for CK20. Therefore, the umbilical lesion was consequently diagnosed as metastasis from pancreatic tail cancer, representing SMJN. The patient died two months after the initial presentation. Conclusions: Ulcerated umbilical lesions should warrant clinical consideration of Sister Mary Joseph’s nodule, as they can serve as a critical diagnostic clue to a deeply situated pancreatic tail cancer.