What is a Krukenberg tumor?

Krukenberg Tumor: Definition and Clinical Significance

A Krukenberg tumor is a metastatic ovarian tumor characterized by the presence of signet ring cells, most commonly originating from the stomach (42.5%), but also from colorectal (26.1%), breast (9.3%), and other primary sites. 1

Pathological Characteristics

• Definition: Metastatic adenocarcinoma to the ovary containing at least 10% signet ring cells 2
• Histological features:
  • Bilateral ovarian involvement in 64.3% of cases 1
  • Discrete tumor lobules separated by striking edema 2
  • Various histological patterns including nests (88%), cords (82%), diffuse sheets (82%), and single cells (71%) 2
  • Signet ring cells typically comprise 2-70% (mean 33%) of tumor cells 2

Primary Sites of Origin

1. Stomach (most common - 42.5%) 1
2. Colorectal (26.1%) 1
3. Breast (9.3%) 1
4. Appendix (5%) 1
5. Other sites including pancreas 3

Clinical Presentation

Krukenberg tumors often present with non-specific symptoms, making early diagnosis challenging:

• Ascites (51.7%) - most common presentation 1
• Palpable abdominal/pelvic mass (31.3%) 1
• Abdominal pain (29.3%) 1
• Abdominal distention (28.7%) 1
• Irregular vaginal bleeding (9.1%) 1
• Asymptomatic in 11.2% of cases 1

Diagnostic Features

• Timing: 48.7% are synchronous with the primary tumor, while others are metachronous 1
• Size: 40.5% have a diameter ≥10 cm 1
• Extent: 55.3% show extraovarian extension and 49% have peritoneal involvement 1
• Age distribution: 39.7% of patients are ≥50 years old 1
• Menopausal status: 39.8% occur in postmenopausal women 1

Clinical Significance and Prognosis

Krukenberg tumors generally indicate advanced disease with poor prognosis:

• They represent distant metastasis (M1) in cancer staging 4
• In gastric cancer patients with ovarian metastasis (Krukenberg tumor), systemic chemotherapy is the main treatment 4
• Some retrospective studies suggest that systemic chemotherapy combined with surgical resection of the primary tumor and/or ovarian metastasis may provide survival benefits in selected patients, extending median overall survival from 6-9 months to 19-23.7 months 4

Key Distinguishing Features

• Breast origin: Tumors from breast primaries typically lack features characteristic of gastrointestinal origin such as extracellular mucin, intestinal-type glands, dirty necrosis, microcysts, and goblet cell carcinoid-like foci 2
• Gastric origin: Often associated with peritoneal spread and more aggressive clinical course

Clinical Pitfalls

• Krukenberg tumors may be misdiagnosed as primary ovarian tumors due to their presentation as ovarian masses
• The primary tumor may be occult or small, requiring thorough investigation
• The diagnosis should prompt a search for the primary tumor site if not already identified
• Delayed diagnosis is common due to non-specific symptoms, which negatively impacts patient outcomes 1

Remember that Krukenberg tumor is not a primary ovarian cancer but represents metastatic disease, and treatment should be directed at both the primary tumor and the metastatic disease for optimal management.