Reactive Lymphadenopathies.

Lymphadenitis in the pediatric population frequently is benign and self-limited, often caused by infections. In children with refractory symptoms, lymph node biopsy may be indicated to rule out malignancy or obtain material for culture. Acute bacterial infections typically show a suppurative pattern of necrosis with abscess formation. Viral infections are associated with nonspecific follicular and/or paracortical hyperplasia. Granulomatous inflammation is associated with bacterial, mycobacterial, and fungal infections. Toxoplasma lymphadenitis displays follicular hyperplasia, monocytoid B-cell hyperplasia, and clusters of epithelioid histiocytes. Autoimmune and noninfectious inflammatory disorders are included in differential diagnosis of lymphadenitis. Infectious mononucleosis and Kikuchi-Fujimoto lymphadenitis may mimic Hodgkin and non-Hodgkin lymphomas.