Acquired toxoplasmic lymphadenitis with demonstration of the cyst form

Toxoplasmic Lymphadenitis Presenting as a Tiny Neck Tumor

(1) Background: Toxoplasmic lymphadenitis (TL), caused by the protozoan Toxoplasma gondii, is a worldwide zoonosis. We report a case of TL in the head and neck region diagnosed using ultrasound (US)-guided fine needle aspiration cytology (FNAC), serological tests, and pathological findings. (2) Case Presentation: A 51-year-old female with a chief complaint of a left posterior neck mass that had been growing for approximately 2 weeks. TL was confirmed by histopathological examinations and serological tests. US-guided FNAC and en bloc resection of the lymph node were performed. The diagnosis was confirmed as TL in the neck. (3) Conclusions: We suggest that US-guided FNAC should be considered as the first-line test for assessing a tiny mass before a definitive treatment is chosen.

Toxoplasma cyst detection in Piringer-Kuchinka lymphadenitis. Report of two cases and literature review

The diagnosis of acute toxoplasmic lymphadenitis is traditionally based on the combination of lymph node excisional biopsy with specific tests. The classic triad (marked follicular hyperplasia, small irregular clusters of epithelioid histiocytes in germinal centers, and sinusoidal distension by monocytoid B lymphocytes) is considered diagnostic of the so-called Piringer-Kuchinka lymphadenitis. Toxoplasma gondii organisms have been exceptionally disclosed in such histopathological setting, establishing the diagnosis of toxoplasmic lymphadenitis. Two cases of Piringer-Kuchinka lymphadenitis with toxoplasma cyst demonstration are reported, along with a complete review of the literature.

Specificity of the histopathological triad for the diagnosis of toxoplasmic lymphadenitis: polymerase chain reaction study

Toxoplasmosis is a common cause of lymphadenopathy, but toxoplasmic cysts are not usually found in histological sections used for establishing diagnosis, except on extremely rare occasions. The histopathological triad of florid reactive follicular hyperplasia, clusters of epithelioid histiocytes, and focal sinusoidal distention by monocytoid B cells has been considered to be diagnostic of toxoplasmic lymphadenitis, but the validity of the histopathological triad is based indirectly on serological correlation only. The demonstration of Toxoplasma gondii DNA in lymph nodes displaying the histopathological triad will indicate the validity of the histopathological triad as the criterion for the histopathological diagnosis of toxoplasmic lymphadenitis. We used frozen tissues of 12 lymph nodes with the histopathological triad and tissues of 27 lymph nodes from patients with various other conditions (including 13 cases of follicular lymphoid hyperplasia, FLH; three cases of dermatopathic lymphadenopathy, DPL; two cases of plasmacytosis; two cases of Castleman's disease; two cases of metastatic adenocarcinoma; and five cases of lymphoma) to detect T. gondii DNA by polymerase chain reaction. Ten out of 12 lymph nodes with the triad and six out of 27 lymph nodes without the triad were positive for T. gondii DNA. Thus, the sensitivity of the triad was 62.5% (10/16) and the specificity was 91.3% (21/23). The predictive value of positive tests was 83.3% (10/12) and the predictive value of negative tests was 77.7% (21/27). The six cases positive for T. gondii DNA without the triad were four cases of FLH, one case of DPL, and one case of plasmacytosis. None of the neoplastic diseases was positive. The false positive and negative cases could be due to sampling problems or past T. gondii infection. The results confirm that the histopathological triad is highly specific for the diagnosis of toxoplasmic lymphadenitis and can be used confidently.

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

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.

Bone marrow involvement by disseminated toxoplasmosis in acquired immunodeficiency syndrome: the value of bone marrow trephine biopsy and immunohistochemistry for the diagnosis

A bone marrow biopsy was performed on four patients with acquired immune deficiency syndrome (AIDS) for a long-running course fever of unknown origin associated with a recent pancytopenia. In the four cases, striking histological similarities, such as interstitial edema, foci of necrosis and only few scattered or clustered histiocytes, were found. Near or in the foci of necrosis, free forms, and pseudocysts of Toxoplasma gondii were observed not only in the cytoplasm of macrophages and of some granulocytes, but also within megakaryocytes. No sign of other parasitic, bacterial, or fungus infection has been found. The diagnosis was confirmed by immunohistochemistry in the four cases and ultrastructural examination in one case. This case study stresses the importance of bone marrow histological changes for the diagnosis of severe toxoplasmosis in AIDS patients and particularly the localization of T gondii within the cytoplasm of megakaryocytes.

Two cases of acquired toxoplasmic lymphadenitis. Light and electron microscopic and immunohistochemical studies

We report two cases of acquired toxoplasmic lymphadenitis, one with toxoplasmic cysts and the organisms of Toxoplasma gondii and the other with the organisms only. These cysts and organisms were observed in paraffin-embedded sections, touch smears and ultrathin sections for electron microscopy. Touch smears were especially valuable for the quick and accurate diagnosis of toxoplasmic lymphadenitis. We also studied immature sinus histiocytosis (ISH) in these cases. The predominant cells of ISH were confirmed to be B lymphocytes immunohistochemically, the majority being positive for polyclonal surface IgM. ISH was observed in the perifollicular and paracortical areas surrounding post-capillary venules (PCV), whereas the sinuses were only partially involved.