A histopathology slide from a debrided necrotic turbinate of a diabetic patient shows broad, ribbon-like, aseptate hyphae with right-angle branching. Which organism is responsible?
- A Aspergillus fumigatus
- B Rhizopus arrhizus ✓
- C Candida albicans
- D Fusarium species
Correct answer: B. Rhizopus arrhizus
Explanation
Mucorales such as Rhizopus produce broad, pauciseptate, ribbon-like hyphae that branch at right angles and show angioinvasion, the hallmark of rhino-orbital-cerebral mucormycosis. Aspergillus, the best distractor, shows narrow, septate hyphae with acute angle (45 degree) dichotomous branching. Candida produces budding yeasts with pseudohyphae, and Fusarium shows septate hyphae with vesicles but not the aseptate ribbon pattern.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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