Sister Mary Joseph's nodule.

Background: Sister Mary Joseph's nodule (SMJN) represents an unusual clinical feature of metastatic deposit at the umbilicus originating from an intra-abdominal malignancy.

Objective: To outline the paucity of such a condition, review the associated pathologies, and demonstrate the importance of clinical and histopathologic correlation.

Methods: Case report of a 75-year-old man with vesical and prostatic cancers treated 2 years prior to presenting with an umbilical lesion. Histopathologic and radiologic examinations were performed to confirm the clinical diagnosis.

Results: Histopathology of the umbilical biopsy revealed a carcinoma of urothelial origin, but immunohistochemistry suggested a squamous cell carcinoma. Clinically, the lesion did not support a diagnosis of primary squamous cell carcinoma; in addition, the positron emission tomographic scan revealed a captation at the ureterovesical junction that was compatible with vesical cancer relapse.

Conclusions: SMJN is a rare but typical cutaneous metastasis of internal malignancy, and its recognition is of great importance because it may be the first presenting sign in a patient with an unknown malignant disease.