organized hematoma of the maxillary sinus: report of two cases

Introduction: organized hematoma of the maxillary sinus (ohms) is a rare benign disease that can be locally aggressive. the diagnosis of this condition is challenging. case reports: we report two cases of ohms presented with recurrent nasal bleeding, nasal obstruction and anosmia. radiological findings were suggestive of a vascularised lesion in the first case and a malignant tumor of the maxillary sinus in the second case. both patients underwent an endonasal endoscopic surgery, there was no recurrence at 19 months’ and six months’ follow-up respectively.   conclusions: ohms should be included in the differential diagnosis if a patient presents with history of recurrent epistaxis and nasal obstruction and radiological findings reveal an expansible maxillary mass with or without bone erosion. correct preoperative diagnosis is important to avoid unnecessary extensive surgery. the prognosis is very good and minimally invasive surgery such as endonasal endoscopic surgery can cure it completely.