Inflammatory pseudotumor (IP) is a clinically aggressive but histologically benign condition of unknown cause. It rarely appears in the nasal cavity and sinuses. Here, we describe a 24-year-old female with the main symptom of right nasal obstruction. Examinations showed dilation in the right maxillary sinus and a pale neoplasm in the nasal cavity. The neoplasm was completely excised under endoscope. Postoperative pathology showed significant proliferation of plasma cells and lymphocytes, indicating the presence of IP. No recurrence was found during 20 months of follow-up. Only 28 cases (10 males and 18 females, average 41.04 years) have been reported on Pubmed. The main clinical manifestations were nasal obstruction, epistaxis, facial swelling and pain, eyeball protrusion, diplopia, and other ocular symptoms. Inflammatory pseudotumor always erodes the surrounding bone and requires active treatments. Surgery is the optimal option with a good prognosis.