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

A Practical Guide to the Role of Ancillary Techniques in the Diagnosis of Infectious Agents in Fine Needle Aspiration Samples

Fine needle aspiration samples and small biopsies provide a minimally invasive diagnostic modality for mass lesions. When an infectious process is suspected based on initial evaluation, ancillary techniques can assist in making a specific diagnosis. Here we review the cytopathology that should prompt additional testing and review the availability and interpretation of special stains, immunohistochemistry, and in situ hybridization. In addition, this review addresses when special cultures may be necessary and the use of newer molecular techniques for pathogen identification.

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

BACKGROUND

There are only very few reports of cervical toxoplasma lymphadenitis being diagnosed exclusively via fine-needle aspiration cytology (with serology).

CASE REPORT

We describe a case of toxoplasma lymphadenitis that was successfully diagnosed by fine-needle aspiration cytology. The case involved a male patient who was immunocompromised as a result of recurrent acute myelogenous leukaemia with cervical lymphadenopathy. The biopsy showed typical features of a well-defined pseudocyst containing Toxoplasma gondii tachyzoites.

CONCLUSION

Toxoplasma lymphadenitis is a common cause of lymph node enlargement. Fine-needle aspiration cytology is a useful method for diagnosing and differentiating toxoplasma lymphadenitis from more serious causes of lymphadenopathy, such as metastatic lymphadenopathy or lymphoma.

Fine-needle aspiration cytology of subcutaneous toxoplasmosis: A case report

Toxoplasmosis is a common opportunistic infection in patients with AIDS in whom it typically presents as encephalitis, pneumonia, lymphadenitis, and myocarditis. Skin involvement is very rare and, to our best knowledge, Toxoplasma gondii forming a subcutaneous mass has not been reported. Here, we report the findings of an interesting case of subcutaneous toxoplasmosis with the cytological appearance of an inflammatory fibrovascular lesion in a HIV-positive patient and discuss the differential diagnosis.

Disseminated nocardiosis diagnosed by fine needle aspiration biopsy: Quick and accurate diagnostic approach

Nocardia is an uncommon pathogen in immunocompetent patients; however, it has been increasingly recognized as a significant opportunistic pathogen in organ transplant patients. Diagnosis of Nocardiosis is usually made by microbiologic culture or cytologic examination of pulmonary specimens including, sputum, and brushing/washings or by histologic evaluation of tissue biopsy material. We report a case of subcutaneous Nocardiosis diagnosed by Fine-needle aspiration biopsy (FNA). The patient is a 66-year-old man with a history of lung transplantation and posttransplant lymphoproliferative disorder who presented with subcutaneous masses in the right upper arm and the left shoulder. FNA was performed in an outpatient clinic setting, with immediate morphologic assessment revealing filamentous branching organisms suspicious for Nocardiosis. Subsequent examination with special stains and microbiologic culture confirmed the diagnosis. The quick and accurate diagnosis by FNA led to emergent and appropriate treatment.

Mycobacterial autofluorescence in Papanicolaou-stained lymph node aspirates: a glimmer in the dark?

This study was undertaken to determine the value of incorporating fluorescence into cytopathological evaluation of lymph node fine-needle aspiration (FNA) specimens suspected of harboring mycobacterial species. The study population consisted of 1,044 HIV-positive and -negative patients referred for FNA to the cytopathology unit of a South African medical school located in a very high HIV prevalence region. Each aspirate was assessed on routine Papanicolaou-stained slides for morphologic characteristics of mycobacterial infection. The same glass slides were then viewed under fluorescent microscopy to determine the presence or absence of mycobacterial autofluorescence. Using multivariate analysis, results of both cytology and fluorescence were compared with mycobacterial culture as the final arbiter of the presence of organisms. In this large clinical study, compared with culture, cytomorphology showed sensitivity of 84.9%, but low specificity of only 50.9%. Fluorescence demonstrated lower sensitivity of 65.9%, but improved specificity of 73.0%. Taken together, positivity of both cytology and fluorescence improved specificity to 81.8%. Fluorescent microscopy is rapid, inexpensive, and cost-effective; neither radioactive materials nor further staining are required. It is felt that this methodology would be of diagnostic benefit if used on morphologically suspicious samples in areas with a high prevalence of HIV and mycobacterial infections. Appropriate therapy could be commenced within hours of FNA, with reduction in the current number of patients lost to follow-up while awaiting results of culture. The technique is readily extended to other FNA types such as deep organ aspirates. Autofluorescence of organisms specifically requires usage of Papanicolaou staining; the technique cannot be used in histopathologic specimens stained with hematoxylin-eosin.

The cytopathology of infectious diseases

Utilizing abrasive, exfoliative, and fine-needle aspiration techniques to diagnose infectious organisms by cytopathologic means is common practice. The increase in the number of immunosuppressed patients in conjunction with the relative ease with which specimens are procured has resulted in the need for rapid interpretation to ensure prompt and adequate treatment. Although some organisms cannot be definitively classified on cytologic preparations, morphologic clues that can guide the pathologist toward rendering a diagnosis helpful to clinicians are often present. In addition, some fungi and parasites rarely identified in cytopathology in the past are more frequently found in cytologic specimens today. This review focuses on organisms found in the United States. Special attention is paid to the morphologic findings on routine Papanicolaou- and Diff Quik-stained cytologic preparations and readily available special stains.