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Liquid-Based Cytology of the Cerebrospinal Fluid in a Case of Cryptococcal Meningitis
1Department of Pathology, Yonsei University Wonju College of Medicine, Wonju, Korea.
Abstract:
Cryptococcus neoformans is the most common microorganism found in cerebrospinal fluid (CSF) cytology and causes life-threatening infections in immunocompromised hosts. Although its cytomorphologic features in conventional smear cytology have been well described, those in liquid-based cytology have rarely been. A 73-year-old woman with diffuse large B-cell lymphoma presented with mental confusion and a spiking fever. To rule out infectious conditions, CSF examination was performed. A cytology slide that was prepared using the ThinPrep method showed numerous spherical yeast-form organisms with diameters of 4-11 μm and thick capsules. Occasional asymmetrical, narrow-based budding but no true hyphae or pseudohyphae were observed. Gomori methenamine silver staining was positive. Cryptococcosis was confirmed in blood and CSF through the cryptococcal antigen test and culture. Liquid-based cytology allows for a clean background and additional slides for ancillary testing, facilitating the detection of microorganisms in CSF specimens, particularly when the number of organisms is small.
Insights
Liquid-based cytology effectively detects Cryptococcus neoformans in cerebrospinal fluid (CSF), aiding diagnosis in immunocompromised patients. This method offers a cleaner background and more slides for testing, improving microorganism identification.
Area of Science:
- Medical Mycology
- Diagnostic Cytopathology
- Infectious Diseases
Background:
- Cryptococcus neoformans is a significant cause of life-threatening infections, particularly in immunocompromised individuals.
- Cerebrospinal fluid (CSF) cytology is crucial for diagnosing central nervous system infections.
- Cytomorphologic features of C. neoformans in liquid-based cytology (LBC) are less understood compared to conventional smears.
Purpose of the Study:
- To describe the cytomorphologic features of Cryptococcus neoformans in liquid-based cytology (LBC) of cerebrospinal fluid (CSF).
- To highlight the utility of LBC in diagnosing cryptococcosis, especially in challenging cases.
- To evaluate the effectiveness of LBC in identifying microorganisms in CSF specimens.
Main Methods:
- A case study of a 73-year-old female patient with diffuse large B-cell lymphoma presenting with fever and confusion.
- Cerebrospinal fluid (CSF) examination using the ThinPrep liquid-based cytology method.
- Morphological analysis of yeast-form organisms, including size, capsule presence, and budding characteristics.
- Gomori methenamine silver (GMS) staining for fungal elements.
- Confirmation of cryptococcosis via cryptococcal antigen testing and blood/CSF cultures.
Main Results:
- The ThinPrep slide revealed numerous spherical yeast organisms (4-11 μm) with thick capsules.
- Observed features included asymmetrical, narrow-based budding, characteristic of Cryptococcus.
- Gomori methenamine silver staining was positive, confirming fungal presence.
- Cryptococcosis was subsequently confirmed by antigen testing and culture in both blood and CSF.
Conclusions:
- Liquid-based cytology (LBC) provides a clean background and allows for additional testing, enhancing the detection of microorganisms like Cryptococcus neoformans in CSF.
- LBC is a valuable tool for diagnosing fungal infections, particularly when organism load is low.
- This case underscores the importance of recognizing LBC features of C. neoformans for timely diagnosis and management of cryptococcosis.
