Haemophilus influenzae lymphadenopathy in a patient with agammaglobulinemia: clinical-histologic-microbiologic correlation and review of the literature.

Agammaglobulinemia is the most common primary immunodeficiency, with an incidence of approximately 1 in 250,000 males in the United States. These patients are at risk for frequent recurrent infections, which may become fatal if untreated. Patients have increased susceptibility to encapsulated pyogenic bacteria. Haemophilus influenzae is second only to Streptococcus pneumoniae as the bacteria most frequently implicated in infections in these patients. We present a case involving an adolescent boy with X-linked agammaglobulinemia and H influenzae cervical adenopathy, confirmed twice by culture. We correlate the clinical, microbiologic, and histologic findings. Owing to the severity of infections in this population, surgical intervention is more common than in the immunocompetent population. This description may help the pathologist in considering a differential diagnosis when examining a diagnostic lymph node biopsy in these patients.