Granulomatous hepatitis by Nocardia species: An unusual case

A case of granulomatous hepatitis due to Nocardia is reported here. The case patient was a 63-year-old immunocompetent man who presented with persistent fever, weight loss, and malaise. Radiology suggested an enlarged liver with dense diffuse to multiple tiny micronodular areas of parenchymal involvement, possibly granulomatous. Liver biopsy showed necrotizing granulomas and anti-tuberculosis therapy was initiated, but the patient showed no improvement. A repeat liver biopsy showed similar histopathology; however PCR for Mycobacterium tuberculosis was negative, while MGIT 960 culture grew filamentous Gram-positive bacilli, acid-fast by 1% H₂SO₄, identified biochemically as Nocardia spp. 16S rRNA sequencing confirmed Nocardia spp. A diagnosis of granulomatous hepatitis due to Nocardia spp. was made. Treatment based on drug sensitivity testing was initiated, resulting in a resolution of symptoms. The patient's history revealed that stray dogs adopted by his family had skin lesions, likely canine distemper (two newborn puppies had died recently). Nocardia is known to co-infect animals with distemper. This could have been the possible source of a zoonotic infection to the case patient. Nocardia spp. are seldom reported from sites other than the lungs, skin, or brain; the current case highlights the involvement of the liver. Due to the granulomatous tissue response, it could represent a differential diagnosis of tuberculosis in such cases.