Extra-nodal natural killer/T cell lymphoma (EN-NK/T) is a highly uncommon, aggressive, mature T or NK-cell lymphoma with a high fatality rate. It has a propensity for infiltrating tissues and spreading to the eye. EN-NK/T-NT is marked by polymorphic clinical characteristics, which can make diagnosis difficult and cause delayed management. This report details a 63-year-old Iranian woman who presented initially with left ocular involvement of unknown cause. Ethmoidal sinusitis, upper nasal obstruction, right proptosis, dacryocystitis, and pulmonary nodules developed later as her disease progressed. Biopsies of the orbit, ethmoidal sinus, and pulmonary nodules were significant for EN-NK/T cell lymphoma. The patient developed and was treated for Covid-19. Due to the progressive lymphoma, chemotherapy was initiated after recovery from Covid-19. After starting the first course of chemotherapy, the patient's condition deteriorated rapidly with the possibility of pulmonary embolism, and she expired inAugust, 2021 2021. This case highlights the diagnostic difficulty of EN-NK/T cell lymphoma and demonstrates its rarity and ability to mimic other diseases.