Radiological Case of the Month FREE

Figure 1. Top and bottom abdominal computed tomograms have multiple well-defined low-attenuation lesions of the liver parenchyma and a single low-attentuation lesion of the spleen.

Figure 2. Real-time ultrasound examination of the liver shows clearly defined hypoechoic liver lesions (arrows) that are not fluid containing.

Serum titers for Bartonella (formerly Rochalimaea) henselae were positive (IgM 1:60, IgG > 1:1024). A diagnosis of cat-scratch disease (CSD) with hepatic and splenic granulomas was made. The patient remained asymptomatic and subsequently the fevers subsided.

A well-recognized, self-limited cause of fever and regional adenopathy, CSD may present in a number of atypical fashions. Involvement of the spleen and liver have been reported increasingly. Margileth et al,¹ reported splenomegaly in 12% of patients in whom the diagnosis was made by skin testing. Splenic involvement may occur with, or independent of, hepatic involvement.^1- 5 Hepatic involvement has been recognized since 1950.⁶ Initial reports identified hepatomegaly in association with a classic presentation of CSD,^7- 8 in association with adenopathy,^2- 3,9- 14 and as the sole focus of involvement in fever of unknown origin.^{4- 5,13- 16} Hepatomegaly may be identified on physical examination,^5,9- 10,13 but in most cases, hepatic involvement was noted only on radiological studies.^{3- 4,11,13- 16} Liver function test results are often normal^{4- 5,11,13,15- 16} or show mild elevation of aminotransferase levels.^3,9- 10,14 Following early description of macroscopic hepatic lesions, the typical ultrasound features are multiple, round, hypoechoic lesions of varying size.^9,15- 16 Computed tomographic features are multiple, scattered, well-circumscribed, low-attenuation lesions of variable size, which become isodense with surrounding hepatic tissue after intravenous contrast enhancement.^7,15- 16 The differential diagnosis for these radiological findings includes other granulomatous disease, pyogenic abscesses, and neoplastic disease. In reported cases, hepatic tissue was obtained by biopsy because of concerns of possible malignancy or unrecognized infectious process. The diagnosis in most reported cases of CSD with hepatic involvement has been established by liver biopsy and/or skin testing with cat-scratch antigen.^{3- 5,9- 11,13,15- 16} Cat-scratch disease causes a granulomatous hepatitis with a histological appearance similar to the granulomas in lymph nodes of individuals with CSD. The typical histological appearance is epithelioid granulomas with central stellate necrosis and many polymorphonuclear lymphocytes.¹⁶ The presence of pleomorphic bacilli by Warthin-Starry silver stain, present in lymph nodes of patients with CSD, has been variable in hepatic lesions. Because of the invasive nature of liver biopsy and the low chance of identifying organisms this way, it is not optimal for diagnosing CSD. Skin testing with cat-scratch antigen is a good alternative diagnostic test and has been the basis for diagnosis in many previously reported cases with hepatic involvement.^{5,9- 11,13,15} An unfavorable feature of this test is that it exposes the patient to potential infectious risks. Since identification of organism(s) causing CSD, safer methods of diagnosis are the polymerase chain reaction for the detection of B henselae DNA^14,17 and antibody testing to confirm the diagnosis of CSD.¹⁴ The use of clinical history, typical radiological findings, and antibody testing allow for a safe means of confirming the diagnosis.

Accepted for publication April 3, 1998.

Reprints: Michael J. Nowicki, MD, Division of Gastroenterology, Department of Pediatrics, Naval Medical Center, 620 John Paul Jones Cir, Portsmouth, VA 23708.