An organized hematoma (OH) is a relatively rare benign lesion of the paranasal sinuses. Traditionally, it has been reported to occur following trauma, surgery, and sinus hemorrhagic lesions and in various bleeding predispositions. OHs are sometimes difficult to differentiate from malignancy because of the similar clinical symptoms and bone destruction. It is especially difficult when OHs occur in the same location as the primary tumor after treatment of a malignant tumor. In this paper, we report two cases of OH that occurred after intra-arterial chemoradiotherapy (IACRT) for maxillary sinus cancer. In one case, FDG accumulation was found in PET/CT and suspected to be a cancer recurrence. However, the postoperative pathology showed no malignant findings. This suggests that OH may show accumulation on 18 F-fluorodeoxyglucose positron emission tomography (FDG-PET). In both cases, bleeding from the maxillary sinus continued after surgery. In one case, recurrence was observed, and in the other, nasal irrigation prevented the pooling of blood in the maxillary sinus, and no recurrence was observed. These cases suggest that OH after IACRT may easily recur because the bleeding continues even after surgery. In such cases, nasal irrigation or preoperative embolization may be helpful to avoid recurrence.
Keywords: FDG-PET; intra-arterial chemoradiotherapy; maxillary sinus cancer; organized hematoma.