RESUMEN
Our search of literature revealed combined elevations of serum cancer antigen 125 levels and rheumatoid factor levels in a patient with peritoneal tuberculosis has rarely been reported. Thus, we describe the case of a 63-year-old female with large abdominal ascites and malignancy was ruled out with biopsy. High levels of serum cancer antigen and rheumatoid factor were noted. Physicians should be aware that tuberculosis infection could induce elevation of rheumatoid factor levels in the absence of rheumatologic symptoms or disease. A high index of suspicion is required because peritoneal tuberculosis is a great mimicker of other abdominal pathology, especially intraabdominal malignancies and can mislead physicians to undergo unnecessary interventions.