Uncomplicated cat-scratch disease: Findings at CT, MR imaging, and radiography

PURPOSE: To describe the epidemiologic, clinical, and imaging features of cat-scratch disease (CSD) to facilitate prompt recognition and noninvasive diagnosis of this condition. MATERIALS AND METHODS: Eight otherwise healthy patients with pet cats presented with the subacute onset of epitrochlear, axillary, or groin masses. All underwent cross-sectional imaging with computed tomography (CT) (n = 1) or magnetic resonance (MR) imaging (n = 7). Five patients underwent radiography of the elbow. RESULTS: In all patients, MR imaging and CT showed a poorly defined soft-tissue mass with extensive surrounding edema in an efferent lymphatic distribution. Radiography revealed only soft-tissue edema in two patients and an ill-defined soft-tissue mass with soft-tissue edema in three patients. Six patients underwent biopsy; the findings of all pathologic specimens supported the diagnosis of CSD. No patients underwent serologic evaluation. All patients were asymptomatic within 4 weeks of beginning antibiotic therapy. CONCLUSION: CSD should be considered in all patients with upper extremity or head and neck adenopathy and a history of cat exposure. Although generally not required for diagnosis, cross-sectional imaging will reveal a mass with surrounding edema in an area of lymphatic drainage.