Sister Mary Joseph's Nodule From Renal Cell Carcinoma: A Case Report.

Sister Mary Joseph's nodules (SMJNs) are umbilical skin metastases of various abdominopelvic malignancies, and they rarely originate from renal cell carcinomas. Radiotherapy is typically used to treat the nodules as a palliative intention. We report a rare case of SMJN that originated from clear cell renal cell carcinoma, which was treated with external beam radiation therapy (EBRT) and interstitial brachytherapy (ISBT). A 74-year-old male patient with a history of left renal cell carcinoma developed an umbilical nodule which was diagnosed as SMJN. The patient underwent EBRT (30 Gy in 10 fractions) and ISBT (12 Gy in two fractions), leading the nodule to complete resolution. This case report might support that radiotherapy, including ISBT, is effective for the treatment of SMJN from renal cell carcinoma.