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. Diagn. Cytopathol. 2000;22:11–15. © 2000 Wiley‐Liss, Inc.

Toxoplasma lymphadenitis diagnosed by fine-needle aspiration cytology: a rare finding

“…Therefore, confirmation of active disease by other serological methods is always desirable. For this purpose, enzyme-linked immunosorbent assay and indirect immunofluorescence methods are available for titration of the parasite-specific IgM antibody 4 – 6 …”

“…There are few reports of cervical toxoplasma lymphadenitis cases being diagnosed exclusively by fine-needle aspiration cytology (with serology) 5 , 6 . Fine-needle aspiration cytology typically shows microgranulomas, consisting of small clusters of characteristic epithelioid histiocytes with only a few mature lymphocytes, and no evidence of necrosis, suppuration or giant cells, on a background of reactive lymphoid hyperplasia 7 .…”

“…Fine-needle aspiration cytology typically shows microgranulomas, consisting of small clusters of characteristic epithelioid histiocytes with only a few mature lymphocytes, and no evidence of necrosis, suppuration or giant cells, on a background of reactive lymphoid hyperplasia 7 . Very few reports have defined the cytological criteria for a diagnosis of toxoplasma lymphadenitis 6 – 8 . There is a similar lack of reports on histopathological analysis.…”

“…There is a similar lack of reports on histopathological analysis. The histological criteria for a diagnosis of toxoplasma lymphadenitis include follicular hyperplasia with preservation of lymph node architecture, focal proliferation of transformed monocytoid B lymphocytes and small, scattered clusters of large, epithelioid-like histiocytes (with larger aggregates of these cells defined as granulomas) 5 , 6 Toxoplasma lymphadenitis was successfully diagnosed by fine-needle aspiration cytologyThis method is useful for differentiating toxoplasma lymphadenitis from more serious causes of lymphadenopathyToxoplasma lymphadenitis can be diagnosed by haematoxylin and eosin staining of tissue sections or immunohistochemical analysis of fine-needle aspirates…”

“…Tissue cysts are very rarely identified in tissue sections (less than 1 per cent of all cases), and hardly ever in cytological smears 7 . In addition, the identification of tachyzoites or bradyzoites in histological preparations has rarely been reported, and only a few studies have described these structures in fine-needle aspiration cytology smears 6 – 8 . Zaharopoulos reported pseudocysts (tachyzoites in histiocytes), with free tachyzoites observed in the background 6 .…”