Value of Imprint Cytology for the Rapid Diagnosis of Mucormycosis in the COVID-19 Pandemic Setting – A Pilot Study

Abstract

The second wave of the coronavirus disease 2019 (COVID-19) pandemic recorded a surge in rhino-orbital-cerebral mucormycosis (ROCM) infection in COVID-19-positive patients with diabetes and on concomitant steroid therapy. The rapidly progressive and devastating nature of the disease necessitated prompt diagnosis and early intervention to improve patient outcomes. Histopathology and fungal culture remain essential tools; however, these investigations have long and variable turn-around times (TATs) and may delay the initiation of treatment. Frozen section is not widely available and should be avoided in COVID-19-positive cases due to the risk of aerosol production and droplet exposure. In cases with high clinicoradiologic suspicion for mucormycosis, imprint cytologic evaluation provides a rapid diagnosis. Familiarity with fungal cytomorphology, awareness of morphologic pitfalls, and implementation of a standardized reporting format aid in diagnostic accuracy. Eighteen COVID-19-positive patients, who were admitted to our hospital with clinical suspicion of mucormycosis during June and July 2021, were included in the study. We used nasal or oral imprint cytology for the initial, rapid detection of Mucor. Cytology findings were correlated with histopathology and fungal culture results. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. The sensitivity, specificity, PPV, and NPV were 100%, 100%, 100% and 100%, respectively. This study showed that imprint cytology can be a rapid, cost-effective, first-line diagnostic modality in Mucor diagnosis.