The Role of Histopathological Examination in the Diagnosis of Cutaneous Sporotrichosis Caused by Sporothrix globosa: A Retrospective Analysis and Reassessment

BACKGROUND: Due to the paucity of fungal elements in the tissue, the sensitivity of histopathological tests for the diagnosis of cutaneous sporotrichosis remains low, particularly for low-virulent Sporothrix species. OBJECTIVES: We retrospectively analysed and re-evaluated the role of histopathological examination in the diagnosis of cutaneous sporotrichosis caused by Sporothrix globosa. METHODS: Retrospective analysis and pathological reassessment were conducted for 69 sporotrichosis cases caused by S. globosa between 2013 and 2024. Statistical analysis using prevalence ratios was conducted to characterise the clinicopathological and epidemiological aspects. RESULTS: Histopathological examination revealed mixed inflammatory cell infiltration and granulomatous changes in all cases. Periodic acid-Schiff (PAS) staining was performed in 29 tissue specimens, with positivity observed in 4 cases (13.8%, 4/29). Following supplemental staining and re-evaluation of the slides, PAS staining revealed positivity in 50.7% (35/69) of cases, demonstrating yeast forms (91.4%, 32/35) with asteroid bodies (n = 2) and rare hyphae (n = 1). CONCLUSIONS: Currently, the role of histopathological examination in the diagnosis of sporotrichosis is limited. Our study showed that the frequency of detecting S. globosa based on histopathological examination is considerably high. Nevertheless, achieving high positive rates necessitates the collaborative efforts of experienced mycologists. The predominance of suppurative granulomas or neutrophils is related to the presence of the fungus in tissue sections from human patients.