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Formation of mucosal polyps in the nasal and maxillary sinus cavities by infection
T Norlander1, M Fukami, K M Westrin
1Department of Otorhinolaryngology, Karolinska Institute, Huddinge Hospital, Sweden.
Abstract:
Unilateral maxillary sinusitis was experimentally induced in New Zealand White rabbits with Streptococcus pneumoniae serotype 3, Bacteroides fragilis NCTC 9343, and Staphylococcus aureus V8. In another group of rabbits, sinusitis was induced by blocking of the sinus ostium only. Bacteriologic and light microscopic analysis was performed after 5 days to 1 month. Granulation-like polyps developed after deep mucosal inflammatory trauma initiating fibroblast proliferation, angiogenesis, and epithelial migration to cover the polyp. In regions of a more superficial trauma-characterized by epithelial desquamation and fibroblast growth-proliferation and differentiation of basal cells resulted in the formation of microcavities dissecting off edematous polyps. Polyps could be found in all sinusitis groups, irrespective of inducing agent. The cellular events of polyp formation appear to be the result of a continuous inflammatory reaction and are not directly related to the presence of a certain microorganism. Instead, the potential of any microorganism to induce a deep mucosal trauma or epithelial desquamation seems essential for its ability to initiate polyp formation.
Insights
Sinusitis can cause polyp formation through inflammation, not specific bacteria. Deep mucosal trauma, regardless of the cause, is key to developing these sinus polyps.
Area of Science:
- Pathology
- Microbiology
- Otolaryngology
Background:
- Sinusitis is a common condition often associated with polyp formation.
- The specific role of microorganisms versus inflammatory processes in polyp development remains an area of investigation.
Purpose of the Study:
- To investigate the cellular mechanisms of polyp formation in experimental maxillary sinusitis.
- To determine if specific microorganisms are essential for initiating polyp development.
Main Methods:
- Experimental induction of unilateral maxillary sinusitis in rabbits using Streptococcus pneumoniae, Bacteroides fragilis, and Staphylococcus aureus, or ostial blockage.
- Bacteriologic and light microscopic analysis over 5 days to 1 month.
Main Results:
- Granulation-like polyps formed in all sinusitis groups, irrespective of the inducing agent.
- Polyp development involved deep mucosal inflammatory trauma, fibroblast proliferation, angiogenesis, and epithelial migration.
- Superficial trauma led to microcavity formation and polyp dissection.
Conclusions:
- Sinus polyp formation is a result of continuous inflammatory reactions, not solely dependent on specific microorganisms.
- The capacity of an agent to induce deep mucosal trauma or epithelial desquamation is critical for initiating polyp formation.