Lymph node biopsy specimens and diagnosis of cat-scratch disease

Abstract

We report microbiologic analysis of 786 lymph node biopsy specimens from patients with suspected cat-scratch disease (CSD). The specimens were examined by standard, cell culture, and molecular methods. Infectious agents were found in samples from 391 (49.7%) of 786 patients. The most commonly identified infectious agent was Bartonella henselae (245 patients, 31.2%), the agent of CSD. Mycobacteriosis was diagnosed in 54 patients (6.9%) by culture and retrospectively confirmed by using a specific real-time PCR assay. Neoplasm was diagnosed in 181 specimens suitable for histologic analysis (26.0%) from 47 patients. Moreover, 13 patients with confirmed Bartonella infections had concurrent mycobacteriosis (10 cases) or neoplasm (3 cases). A diagnosis of CSD does not eliminate a diagnosis of mycobacteriosis or neoplasm. Histologic analysis of lymph node biopsy specimens should be routinely performed because some patients might have a concurrent malignant disease or mycobacteriosis.

Figure 1

Distribution of patients by age and group. Cat-scratch disease (CSD) group, patients with Bartonella-positive PCR results in lymph node samples; Non-CSD group, patients with Bartonella-negative PCR results. For patients <25 years of age, p = 0.032 for CSD group versus non-CSD group.

Figure 2

Detection of Bartonella henselae in the lymph node of a patient with cat-scratch disease and tuberculosis by direct immunofluorescent assay with a monoclonal antibody (magnification ×400).