Sister Mary Joseph's nodule: A rare metastasis of hilar cholangiocarcinoma: A new case report and review of the literature.

Introduction: Sister Mary Joseph's Nodule (SMJN) is a rare clinical sign of metastatic abdominal malignancies, particularly cholangiocarcinoma, with limited reported cases in the literature. SMJN is associated with poor prognosis, often indicating advanced disease with widespread metastasis. Case presentation: we present a new case report of SMJN in a 46-year-old patient who presented with ten days of right upper quadrant pain, obstructive jaundice, and fever. Physical examination revealed obstructive jaundice with scratchy lesions in the trunk and tenderness in the right upper quadrant, along with a two-centimeter protuberant, tender ulcerated umbilical nodule. Despite previous management with antibiotics and local care, the nodule had been progressively growing over a month. Imaging studies revealed a hilar cholangiocarcinoma with extensive local invasion and multiple distant metastases, including cutaneous involvement at the umbilicus. Biopsies of the umbilical lesion confirmed metastatic adenocarcinoma of the biliary tree. Palliative measures, including biliary stent placement and chemotherapy, were initiated. Discussion: SMJN is a rare but notable cutaneous manifestation associated with advanced intra-abdominal malignancies. Although often linked to gastric, pancreatic, and ovarian cancers, it is uncommonly reported with cholangiocarcinoma. SMJN typically signifies a late-stage, metastatic progression, with prognosis largely determined by the underlying primary cancer's aggressiveness and the extent of metastasis. In this case, SMJN presented alongside other symptoms of advanced disease, such as obstructive jaundice and extensive local invasion, underscoring its prognostic significance. Recognition of SMJN is essential for prompt diagnosis and initiation of palliative interventions in patients with suspected metastatic disease. This case adds to the limited literature on cholangiocarcinoma-associated SMJN and highlights the need for awareness among clinicians regarding atypical metastatic presentations, which may facilitate earlier diagnosis and tailored care strategies. Conclusion: This case emphasizes the importance of recognizing SMJN as a rare but crucial indicator of advanced cholangiocarcinoma. It highlights the clinical challenges posed by metastatic cholangiocarcinoma and underscores the need for a comprehensive approach to palliative care in patients with SMJN.