Abstract
Acute lymphoblastic leukemia (ALL) is a hemopoietic malignancy of the bone marrow that rarely invades the sinonasal area. If infiltration of paranasal sinuses occurs, it may lead to rhinosinusitis and orbital complications that need aggressive treatment. In this report, a 26-year-old male patient who had a history of ALL and had one relapse, suffered from rapid progression of right periorbital pain and exophthalmos, which usually presented in patients with orbital complications of sinusitis. A sinus computed tomography showed right maxillary and ethmoid sinus opacification with orbital bone destruction. Urgent endoscopie sinus surgery (ESS) was performed for orbital decompression and histopathologic diagnosis. Pathology revealed lymphoblast infiltration and inflammation of respiratory mucosa. Subsequent bone marrow aspiration cytology confirmed the diagnosis of a second relapse of ALL. Obstructive causes of sinusitis should be evaluated in patients with ALL. ESS has proven to be effective in obtaining tissue for histopathologic diagnosis, and in treating patients with sinusitis with orbital complications.