What is a Sister Mary Joseph nodule and what is the recommended diagnostic work‑up and management?

Sister Mary Joseph Nodule: Definition, Diagnostic Work-Up, and Management

A Sister Mary Joseph nodule is a metastatic umbilical tumor deposit from an intra-abdominal or pelvic malignancy that carries a grave prognosis with only 13.5% two-year survival, requiring immediate biopsy and comprehensive staging to identify the primary source. 1

Definition and Clinical Significance

A Sister Mary Joseph nodule (SMJN) represents a palpable periumbilical cutaneous metastasis originating from intra-abdominal or pelvic malignancies. 1, 2 The most common primary sources are:

• Gastrointestinal tract (stomach, colon, pancreas, appendix) 1, 2, 3
• Gynecological organs (ovary, endometrium) 1, 4
• Genitourinary tract 4

Critical pitfall: In 75% of appendiceal carcinoma cases presenting as SMJN, the umbilical nodule was the initial clinical manifestation of previously unsuspected cancer, appearing 1-7 months (median 5 months) before pathologic confirmation. 1 This underscores that SMJN often represents the "tip of an iceberg" of extensive intra-abdominal disease. 4

Immediate Diagnostic Work-Up

Step 1: Tissue Diagnosis

Perform core needle biopsy or excisional biopsy of the umbilical nodule immediately to establish the diagnosis and determine the primary tumor type. 1, 2 Core needle biopsy is preferred over fine-needle aspiration as it provides superior sensitivity, specificity, and correct histological grading. 5

Step 2: Cross-Sectional Imaging

Obtain contrast-enhanced CT of the chest, abdomen, and pelvis to:

• Identify the primary malignancy 2, 3
• Assess for peritoneal carcinomatosis or pseudomyxoma peritonei 1
• Evaluate extent of metastatic disease 4
• Stage the disease comprehensively 5

Imaging pearls: Radiologists frequently misdiagnose or overlook SMJN on CT imaging. 2 Maintain high index of suspicion when evaluating any umbilical soft tissue abnormality in patients with known malignancy or unexplained abdominal symptoms. 2

Step 3: Targeted Evaluation Based on Clinical Context

For women ≥30 years: Obtain diagnostic mammogram with ultrasound to evaluate for occult breast cancer. 5

Physical examination focus:

• Palpate for other sites of adenopathy (inguinal, axillary, cervical) 5
• Perform thorough abdominal examination for masses or ascites 4
• In women, perform pelvic examination for ovarian masses 4

Step 4: Tumor Markers

Consider obtaining:

• CA-125 (ovarian primary) 4
• CEA and CA 19-9 (gastrointestinal primary) 3, 6
• AFP (hepatobiliary primary) 6

Management Approach

Multidisciplinary Referral

Refer immediately to a specialist oncology multidisciplinary team for treatment planning, as management requires coordination between medical oncology, surgical oncology, and radiation oncology. 5 Discrepancy rates between diagnoses made outside specialist centers range from 8-35%, highlighting the critical importance of expert evaluation. 5

Treatment Strategy

Management depends on the identified primary malignancy and extent of metastatic disease:

For localized disease with identified primary:

• Consider surgical resection of primary tumor if feasible 3
• Systemic chemotherapy based on primary tumor type 3, 6
• Palliative resection of umbilical nodule for symptomatic relief 4

For extensive metastatic disease:

• Palliative systemic chemotherapy 1, 4
• Symptomatic management of umbilical lesion 4
• Early goals-of-care discussions given poor prognosis 1

Prognosis and Counseling

The presence of SMJN indicates advanced metastatic disease with uniformly poor prognosis: two-year survival is only 13.5% regardless of primary cancer etiology. 1 This finding should prompt:

• Immediate prognostic counseling with the patient and family 1
• Early palliative care involvement 1
• Realistic discussion of treatment goals (life-prolonging vs. comfort-focused) 1

Key Clinical Pearls

Pattern recognition is essential: Any solitary umbilical nodule in an adult should prompt immediate investigation for underlying intra-abdominal malignancy, even in the absence of other symptoms. 1, 2 The likelihood of SMJN presenting as the initial clinical feature increases in patients with extensive intraperitoneal metastasis. 1

Do not delay: Early diagnosis through prompt biopsy and staging can alter management and potentially improve outcomes, particularly for pancreatic and pancreatobiliary cancers where surgical intervention may still be possible. 3, 6