MRSA Liver Abscess Associated With Very High CA 19-9 Levels

Abstract

Case Report: An 85-year-old female presented with left-sided chest pain. Past medical history: breast cancer, modified radical mastectomy 20 years ago, a-fib, and hypertension. CTA-chest showed no pulmonary embolism, but incidentally showed cystic lesions in the liver, including 1 large complex cystic mass in the left lobe of the liver. Exam: temperature of 101.8° F, BP:95/53 mmHg. Cardiac: irregularly irregular rhythm. Abdomen: generalized abdominal tenderness. Labs: AST:56 IU/L, WBC:12.8 K/uL, neutrophils:80%. Metastatic disease to the liver was suspected. CEA and alpha fetoprotein were normal, but the CA19-9 was 1387 U/mL (normal: 0-35). Liver ultrasound revealed right lobe simple cyst and a complex left lobe cyst containing thick septations and soft tissue lobularity, as well as internal echoes. MRI revealed no increased enhancement within the previously visualized complex cyst and no other abdominal pathology. Blood cultures were positive for Klebsiella pneumoniae. She underwent percutaneous drainage of the hepatic cyst, and the culture grew MRSA and Klebsiella. The hepatic cyst wall and abscess cytology study was negative for malignancy. She responded well to antibiotics. Serial measurements of serum CA19-9 showed progressive decline with antibiotic treatment. Discussion: High elevations of CA 19-9 can be seen in various benign diseases, but elevations associated with liver abscess are thought to be rare. High CA 19-9 levels are usually associated with biliary and pancreatic malignancies; in the latter, it is considered an accepted tumor marker, and high concentration in serum signifies a poor prognosis. There are very few documented cases of liver abscess associated with high CA 19-9 levels, and our PubMed search did not identify prior reports associating it with MRSA liver abscess (search terms: CA 19-9, liver abscess, MRSA). Most pyogenic liver abscesses are polymicrobial; mixed enteric facultative and anaerobic species are the most common pathogens. Staphylococcus aureus is only found in around 7% and usually results from hematogenous dissemination from a preexisting infection elsewhere in the body. In our patient, CA 19-9 levels decreased after treatment with appropriate antibiotics, which suggests that CA 19-9 might be a useful marker of treatment response in cases of MRSA liver abscesses.Figure 1