Open-access The diagnostic value of fine-needle aspiration cytology in the early diagnosis of pulmonary cryptococcosis

Abstract

Pulmonary cryptococcosis, an invasive fungal infection caused by Cryptococcus spp., is often misdiagnosed as tuberculosis or lung cancer due to overlapping clinical and radiological features, leading to treatment delays. In this descriptive study, we aim to characterize the diagnostic findings and clinical utility of fine-needle aspiration cytology (FNAC) in a series of patients with pulmonary cryptococcosis, within the context of other available diagnostic modalities. We retrospectively analyzed 10 patients with pulmonary cryptococcosis who underwent imaging-guided percutaneous lung aspiration. Wright-Giemsa-stained cytology smears were examined under oil immersion, enabling clear visualization of the characteristic morphological features of Cryptococcus. In this case series, FNAC provided a rapid cytological diagnosis within two hours in all 10 cases, consistent with the results obtained by metagenomic next-generation sequencing (mNGS) and serological testing. In contrast, conventional smear microscopy showed lower detection rates, and histopathology required longer processing times. The use of FNAC facilitated early diagnosis, enabling timely initiation of antifungal therapy and helping to avoid unnecessary surgical interventions. Our findings suggest that cytomorphological evaluation by FNAC is a rapid and valuable diagnostic tool in the early clinical management of pulmonary cryptococcosis, effectively complementing existing diagnostic methods.