Objective:

To report a rare immune-related cutaneous adverse event (ircAE) of nasal swelling and ulceration in a patient with small cell lung cancer treated with atezolizumab, highlighting its clinical significance.

Key Findings:

• Nasal swelling and ulceration are extremely rare ircAEs associated with atezolizumab, necessitating awareness among clinicians.
• Histopathological findings indicated an immune-mediated reaction rather than metastatic disease, underscoring the need for accurate diagnosis.
• Discontinuation of atezolizumab and glucocorticoid treatment resulted in significant symptom improvement, demonstrating effective management strategies.

Interpretation:

This case highlights the importance of recognizing rare ircAEs in patients receiving immune checkpoint inhibitors, which can prevent misdiagnosis and inappropriate treatment, urging clinicians to remain vigilant.

Limitations:

• The rarity of the reported ircAE limits generalizability.
• Lack of similar case reports in the literature makes it difficult to establish a broader context, emphasizing the need for further research.

Conclusion:

Clinicians should be aware of the potential for rare ircAEs like nasal ulceration in patients treated with atezolizumab, emphasizing the need for careful monitoring and management to ensure timely intervention.