Cytologic features of necrotizing granulomatous inflammation consistent with cat-scratch disease.

Approximately 2,000 cases of cat-scratch disease are reported annually. It is an uncommon cause of unilateral lymphadenopathy in children and adults. We present the cytologic features of necrotizing granulomatous lesions consistent with cat-scratch disease from various sites. Eleven cases from 10 patients with a mean age of 16 yr (range, 2-33 yr) were biopsied by fine-needle aspiration. All gave a history of previous exposure to cats. Two children had atypical presentations; one with multiple hypodense areas within the liver and spleen, and the other with features of encephalitis. Other locations included lymph nodes from axilla, inguinal, preauricular, and cervical areas, and other body sites such as the scapula and the parotid gland. Histologic staging of the inflammatory process was correlated with cytologic features. There were 5 cases of early features, 3 cases in the middle phase, and 3 cases in late stage. The differential diagnosis of each stage is discussed. The 2 children with atypical presentations are described in detail.