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Inflammatory Pseudotumor Due to Actinomycosis Simulating Post-Transplant Lymphoproliferative Disorder
Grecia Lizzetti-Mendoza1, Daniel Reis Waisberg1, Gabriel Bayona-Alvarado1
1Liver and Abdominal Organs Transplantation Division, Department of Gastroenterology, Hospital das Clínicas da Faculdade de Medicina de São Paulo (HC-FMUSP), São Paulo, Brazil.
Introduction:
Hepatic actinomycosis is a rare infection caused by anaerobic, gram-positive Actinomyces bacteria. Liver involvement represents 5% of all actinomycosis cases and usually occurs secondary to intra-abdominal infections, spreading via the porto-mesenteric venous system. Clinical symptoms and imaging findings are typically heterogeneous and nonspecific, often mimicking malignant tumors, which makes diagnosis difficult and frequently one of exclusion. Immunosuppressed patients, including liver transplant recipients, have increased risk and the disease should be considered when a solitary or atypical hepatic mass is detected.
Case Report:
The case discussed involves a female patient who underwent living-donor liver transplantation and biliodigestive anastomosis in 2018 for cirrhosis secondary to hepatitis B virus infection. She developed chronic biliary stenosis managed with periodic exchanges of percutaneous transhepatic biliary drain. In 2024, she presented with catheter displacement and peri-drain bile leakage. An abdominal computed tomography scan revealed a 150 mL hepatic collection compatible with abscess. Percutaneous drainage and antibiotics were started, but poor clinical and radiologic response raised suspicion for post-transplant lymphoproliferative disorder. A guided liver biopsy ultimately identified Actinomyces sp., confirming hepatic actinomycosis. Treatment with intravenous ampicillin for 1 month led to major improvement and 90% lesion resolution. She was discharged on oral amoxicillin-clavulanate for additional 3 months, with outpatient follow-up demonstrating favorable clinical response.
Conclusion:
Although uncommon, hepatic actinomycosis should be considered a possible cause of hepatic masses in liver transplant recipients. Management is mainly conservative with prolonged antibiotics and drainage may be used for refractory cases. Prognosis is generally positive when the condition is adequately treated.
Insights
Hepatic actinomycosis, a rare liver infection, can mimic tumors in transplant patients. Prompt antibiotic treatment and drainage led to significant lesion resolution and favorable outcomes in a liver transplant recipient.
Area of Science:
- Hepatology
- Infectious Diseases
- Transplant Surgery
Background:
- Hepatic actinomycosis is a rare infection caused by Actinomyces bacteria, often presenting as non-specific liver masses.
- Liver involvement is uncommon, typically secondary to intra-abdominal infections, and poses diagnostic challenges due to nonspecific symptoms and imaging.
- Immunosuppressed individuals, particularly liver transplant recipients, are at higher risk and require consideration of this diagnosis for atypical hepatic masses.
Purpose of the Study:
- To highlight hepatic actinomycosis as a differential diagnosis in liver transplant recipients presenting with hepatic masses.
- To present a case study of successful management of hepatic actinomycosis in a liver transplant recipient.
- To emphasize the importance of considering rare infections in post-transplant patients with atypical presentations.
Main Methods:
- A case report of a female liver transplant recipient with chronic biliary stenosis.
- Diagnosis of hepatic actinomycosis was confirmed via guided liver biopsy after initial presentation with a hepatic collection and poor response to standard treatment.
- Treatment involved intravenous ampicillin followed by oral amoxicillin-clavulanate, alongside percutaneous drainage.
Main Results:
- The patient presented with a hepatic collection initially suspected as an abscess or post-transplant lymphoproliferative disorder.
- Liver biopsy confirmed Actinomyces sp. infection, leading to a diagnosis of hepatic actinomycosis.
- Treatment resulted in significant clinical improvement and substantial resolution of the hepatic lesion (90%).
Conclusions:
- Hepatic actinomycosis should be considered in liver transplant recipients with hepatic masses, despite its rarity.
- Conservative management with prolonged antibiotics is the primary treatment strategy.
- Drainage may be necessary for refractory cases, and the prognosis is generally favorable with adequate treatment.
