Demonstration of parasites in toxoplasma lymphadenitis by fine-needle aspiration cytology: report of two cases.

Abstract

Two cases of toxoplasma lymphadenitis diagnosed by fine-needle aspiration (FNA) cytology, in which the microorganisms were identified in the cytologic preparations, are presented. The first case was that of an 8-yr-old boy with bilateral cervical lymphadenopathy of 2-mo duration, in which an FNA specimen of one of the lymph nodes in a Papanicolaou-stained smear disclosed a toxoplasma cyst, and in Wright-Giemsa preparation, dispersed tachyzoites and a pseudocyst. The second case was that of a 52-yr-old man with enlargement of a single lymph node in the neck, of 3-mo duration, FNA of which in Wright-Giemsa preparation disclosed numerous tachyzoites dispersed free in exudate, and also within cells, forming pseudocysts. In both cases, immunocytochemistry by the peroxidase method for Toxoplasma gondii antigen was positive. The tachyzoites seen in Wright-Giemsa preparations, when subjected to fluorescence microscopy, emitted autofluorescence, facilitating their identification. While the presence of parasites in toxoplasma lymphadenitis is quite unusual, having been reported occasionally in histologic preparations and only rarely in cytologic FNA materials, our 2 cases suggest that in active disease, tachyzoites may not be so uncommon in FNA specimens. Besides the use of immunocytochemistry in the diagnosis of the disease, air-dried preparations stained by the Wright-Giemsa method are valuable for the demonstration of such parasites through careful search, along with the possible use of fluorescence microscopy.