IMC Journal of Medical Science

Introduction: Mucormycosis is a rare but deadly fungal infection that often affects those with weakened immune systems. With the rise in predisposing factors such as diabetes, use of steroids, rise in cases of cancer, among others, cases of mucormycosis are increasingly being observed. A surge of cases was noted due to the situation arising out of the COVID-19 pandemic.

Materials and methods: This study analyzed various histo-morphological tissue reaction patterns associated with mucormycosis and explored the utility of crush smear and imprint smear cytology in confirming the presence of fungi. A total of 63 samples were taken. Meticulous history and clinical examination were done. History of COVID-19 infection, diabetes mellitus, hospitalization, intensive care stay, and steroid therapy was taken into account. Biopsy specimens (rhino-orbital, sino-nasal, rhino-cerebral and bone) received in normal saline were first subjected to cytopathological examination using both crush smears and imprint smears and further processed for histopathological examination.

Results: The mean age of the patients was 48.76 ± 13.24 years. Male preponderance was seen with male to female ratio of 1.65:1. An overwhelming majority (92.6%) of patients had a history of COVID-19 infection. Pre-existing diabetes mellitus was found in 83.3% of patients, steroid intake in 72% of patients, and medical oxygen administration in 46.3% of patients. Out of 63 clinically suspected patients, 54 (85.7%) cases were diagnosed with mucormycosis on histopathology. The most common site involved was rhino-orbital (62.9%), followed by sino-nasal (25.9%) and rhino-cerebral (7.4%). Five histo-morphological patterns were identified namely infarct-like necrosis with or without angio-invasion (50%), exudative pattern (24%), mixed pattern (11%), granulomatous (9%) and predominantly histiocytic pattern (6%). With histopathology as gold standard, crush smear cytology yielded a sensitivity of 72.2% (95% confidence interval/CI: 58.4-83.5%), specificity of 77.8% (95% CI: 40.0-97.2%), positive predictive value (PPV) of 95.1% (95% CI: 83.5-99.4%) and negative predictive value (NPV) of 31.8% (95% CI: 13.9-54.9%), with overall diagnostic accuracy of 73.0%. Imprint smear cytology showed marginally better performance with sensitivity of 75.9% (95% CI: 62.4-86.5%), specificity of 77.8% (95% CI: 40.0-97.2%), PPV of 95.3% (95% CI: 84.2-99.4%) and NPV of 31.8% (95% CI: 13.9-54.9%), with overall diagnostic accuracy of 76.2%.

Conclusion: Various histo-morphological patterns encountered on histopathological examination help us keep the suspicion index high and warrant extensive examination for fungi. Histopathology remains the gold standard, providing prompt and definitive diagnosis, essential for establishing surgical and antifungal therapy, prognostication and evaluation of treatment response. Both crush smear and imprint cytology demonstrate high sensitivities (72-76%) and excellent PPVs (>95%), making them valuable rapid diagnostic tools for confirming mucormycosis when positive results are obtained. However, their low NPVs (31.8%) indicate that negative cytology results cannot reliably exclude mucormycosis, and histopathological examination remains mandatory in clinically suspected cases with negative cytological findings.

January 2026; Vol. 20(1):001, DOI: https://doi.org/10.55010/imcjms.20.001

*Correspondence: Mohd. Yasir Zubair, Department of Community Medicine, VALASMC, Etah, UP, India. Email: yasmuhsin@gmail.com.

© 2025 The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License(CC BY 4.0).