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Malignant lymphoma presenting with an elevated serum CA-125 level
1Department of Pathology, Mount Sinai Hospital, Toronto, Ontario, Canada.
Insights
Elevated CA-125 levels in lymphoma patients may stem from reactive mesothelial cells, not tumor cells. This finding broadens the clinical use of CA-125 beyond ovarian cancer monitoring.
Area of Science:
- Oncology
- Immunohistochemistry
- Biomarker Research
Background:
- Cancer antigen 125 (CA-125) is a glycoprotein primarily associated with ovarian carcinoma monitoring.
- Elevated serum CA-125 levels are rarely reported in patients with malignant lymphoma, with unclear pathophysiology.
- Understanding the source of CA-125 in non-ovarian malignancies is crucial for accurate diagnosis and monitoring.
Observation:
- An elderly female patient with lymphoma presented with constitutional symptoms and markedly elevated serum CA-125.
- Post-mortem examination revealed widespread lymphoma with peritoneal involvement.
- Immunohistochemistry showed CA-125 expression in reactive mesothelial cells, but not in lymphoma cells.
Findings:
- The study supports the hypothesis that elevated CA-125 in lymphoma patients originates from reactive mesothelial cells in the peritoneum.
- CA-125 production by mesothelium can occur in various peritoneal diseases, both benign and malignant.
- Lymphoma cells themselves did not exhibit CA-125 immunoreactivity.
Implications:
- The clinical utility of CA-125 may extend beyond ovarian cancer, potentially serving as a marker in other peritoneal diseases.
- This research clarifies a previously misunderstood phenomenon in lymphoma patients with elevated CA-125.
- Further investigation into mesothelial cell involvement in biomarker production is warranted for broader diagnostic applications.
Abstract:
An 80-year-old woman presented with fevers, night sweats, and weight loss. Her serum CA-125 level was markedly elevated (380 U/mL; normal < 35 U/ml). At post-mortem examination, the patient had widespread intermediate-grade malignant lymphoma with extensive infiltration of the greater omentum and pelvic peritoneum. Immunohistochemistry for CA-125 documented intense staining in the reactive mesothelial cells of the peritoneum; the tumor cells were not immunoreactive. CA-125 is a glycoprotein recognized by a monoclonal antibody raised against an ovarian-cancer cell line. Elevated levels have been reported rarely in patients with malignant lymphoma, and the pathophysiology of this finding has not been understood. Our data support the hypothesis that elevated CA-125 levels may reflect production by reactive mesothelium in patients with benign or malignant diseases involving the peritoneum, including malignant lymphoma. The clinical application of this marker, therefore, is broader than the recognized monitoring of patients with ovarian carcinoma.