Disseminated cat-scratch disease in an adult with selective IgA deficiency.

A 51-year-old man with history of undiagnosed pulmonary nodules 4 years prior, presented with right-sided chest pain. Acute cardiac workup was negative, and a chest computed tomography examination demonstrated marked improvement in bilateral pulmonary nodules. A concordant abdominal computed tomography examination showed new subcentimeter hypodense lesions throughout the liver and spleen, mild progressive abdominopelvic lymphadenopathy, and new small lytic lesions of T11 and L4 vertebrae. A positron emission tomography examination demonstrated hypermetabolic activity of these abdominopelvic lesions suggesting metastatic disease. Extensive laboratory workup was negative, aside from IgA deficiency. Eventually, biopsy of a hepatic lesion was performed and compatible with Bartonella species. An elevated Bartonella IgG titer was noted, consistent with Bartonella Hensalae infection, or "cat-scratch disease." Radiographic findings showed marked improvement after clinically appropriate antibiotic therapy.