A 30-year-old man from rural Karnataka presents with recurrent episodes of unilateral nasal obstruction and intermittent epistaxis. Examination shows a pink, friable, polypoidal mass arising from the nasal septum that bleeds readily on touch. Biopsy of the mass shows thick-walled sporangia filled with numerous endospores. The most likely causative agent is:
- A Rhizopus arrhizus
- B Rhinosporidium seeberi ✓
- C Cryptococcus neoformans
- D Aspergillus flavus
Correct answer: B. Rhinosporidium seeberi
Explanation
Rhinosporidiosis, common in India and Sri Lanka and associated with bathing in stagnant water, presents as a friable, vascular, bleeding polyp of the nose, nasopharynx or conjunctiva. Histology shows large thick-walled sporangia containing hundreds of endospores in various stages of maturation. Rhinosporidium seeberi was traditionally grouped with fungi but molecular studies place it among aquatic protists (Mesomycetozoea); Indian examination convention still lists it under mycology. Mucormycosis causes necrotic eschar, not a vascular polyp.
Reference: Paniker's Textbook of Medical Parasitology and Microbiology, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.