S5833 Peliosis Hepatitis Secondary to Bartonella henselae Infection

Introduction: Peliosis hepatis is a rare vascular condition characterized by blood-filled cystic spaces in the liver, often associated with underlying infections, malignancies, or immunosuppression. Bartonella henselae, the causative agent of cat scratch disease, is a known but uncommon cause. Most reported cases occur in immunocompromised individuals, particularly those with HIV/AIDS. Case Description/Methods: A 27-year-old man with multiple prior hospitalizations presented with abdominal pain, weight loss, ascites, and fatigue. He denied alcohol use, recent travel, or medication exposure but reported owning 3 cats. Laboratory evaluation revealed acute kidney injury, nephrotic-range proteinuria, pancytopenia, elevated alkaline phosphatase, and a mildly elevated erythrocyte sedimentation rate. HIV and tuberculosis testing were negative. Ascitic fluid analysis showed high protein content and a low serum-ascites albumin gradient (SAAG <1.1), ruling out portal hypertension. Cytology was negative for malignancy. Abdominal MRI demonstrated multiple arterial-enhancing hepatic lesions without cirrhosis. Esophagogastroduodenoscopy and colonoscopy revealed no abnormalities. Bone marrow biopsy and flow cytometry excluded acute leukemia, high-grade myelodysplasia, plasma cell disorders, and lymphoproliferative disease. Diagnostic laparoscopy with peritoneal biopsies was negative for malignancy or amyloidosis, showing only nonspecific chronic inflammation. A liver biopsy revealed features consistent with peliosis hepatis. Warthin-Starry staining and serologic testing confirmed Bartonella henselae infection. The patient was treated with a 3-month course of doxycycline, leading to resolution of hepatic lesions, normalization of renal function, correction of cytopenias, and complete resolution of ascites. Discussion: In this case, the absence of common risk factors such as immunosuppression or HIV infection obscured the diagnosis. The patient’s systemic findings including cytopenias, renal dysfunction, ascites, and radiographically atypical liver lesions mimicked malignancy or infiltrative disease, leading to extensive workup. This case highlights the importance of considering infectious etiologies, including Bartonella henselae, in patients with multisystem involvement and unexplained hepatic lesions, regardless of immune status. Early recognition is critical, as antimicrobial therapy can lead to complete resolution and prevent unnecessary invasive interventions.