Non Pathogenic Fungal Contaminants in Cytological Specimens: Beware the Imitation

Area of Science:

• Cytopathology
• Mycology
• Diagnostic Microbiology

Background:

• Accurate identification of nonpathogenic fungi in cytology is crucial for diagnostic integrity.
• Fungal elements can be mistaken for pathogenic organisms, leading to misdiagnosis.
• Understanding common fungal contaminants aids cytologists in accurate interpretation.

Purpose of the Study:

• To identify and characterize nonpathogenic fungal contaminants in cytopathology specimens.
• To assess the diagnostic challenges posed by these fungal contaminants.
• To provide insights into the prevalence of specific fungal species in cytological samples.

Main Methods:

• Analysis of over 11,000 cytology specimens including fluids, PAP smears, and FNA samples over one year.
• Inclusion of various sterile and non-sterile body fluids, cervical cytology specimens.
• Microbiological culture correlation and testing of laboratory reagents for fungal presence.

Main Results:

• Fusarium species were the most common fungal contaminants identified.
• Alternaria species were the second most prevalent, with potential implications for phaeohyphomycosis.
• Microbiological cultures were often negative for the contaminants initially but sometimes yielded positive results.

Conclusions:

• Nonpathogenic fungal contaminants are ubiquitous in cytology slides.
• These contaminants act as significant mimics, potentially confusing cytological diagnoses.
• Awareness of common fungal contaminants is essential for cytologists to avoid diagnostic errors.