Reticuloendotheliosis with eosinophilia (Omenn's syndrome). Findings in fine needle aspirate of a lymph node.

Omenn's syndrome is a benign proliferation of Langerhans' type histiocytes accompanied by eosinophilia in a lymph node of an immunoincompetent patient. This paper describes the clinical, immunologic, histologic and fine needle aspiration cytologic findings of such a lymph node taken from a two-week-old infant. The differential diagnosis of lymph node aspirates is discussed, with emphasis on those having a population rich in histiocytes and eosinophils.