Primary clear cell adenocarcinoma of the peritoneum presents as Sister Mary Joseph's nodule: a case report and literature review

Background: Sister Mary Joseph's nodule (SMJN) is a raised nodule around the umbilicus and is often a clinical sign of metastatic malignancy with poor prognosis. Primary clear cell adenocarcinoma of the peritoneum is rare. Herein the authors describe a case of primary peritoneal clear cell adenocarcinoma presenting with SMJN as an initial sign. Case: A 59-year-old woman was admitted into the present hospital complaining of an enlarged, painful umbilical nodule, and increasing abdominal distention. After the biopsy of the peritoneal nodule, primary clear cell adenocarcinoma of the peritoneum was diagnosed. The patient underwent multiple courses of aggressive chemotherapy combined with radiotherapy and surgery and has survived for more than four years. Conclusion: Considering that SMJN is a rare sign of visceral malignancies, clinicians should be aware of this rare clinical sign when determining the differential diagnosis. Umbilical metastasis is usually indicates a poor prognosis. However, the present case suggests that long-term survival is possible.