Extranodal nasal-orbital communicating lesions NK/T cell lymphoma with ocular symptoms as the initial manifestation misdiagnosed as sinusitis and orbital cellulitis: a case report and literature review.

[BACKGROUND] Extranodal natural killer/T cell lymphoma (ENKTL) is a non-Hodgkin lymphoma (NHL) with extranodal presentation.

[CASE PRESENTATION] This report presents a rare case of ENKTL with ocular symptoms as the initial manifestation. Nasal endoscopy was normal. Magnetic resonance imaging (MRI) and sinus computed tomography (CT) scan revealed no evidence of mass or lymphadenopathy. The first hospitalization was misdiagnosed as sinusitis. Ophthalmic examination showed no significant decrease in vision. On 15 April 2025, a functional endoscopic sinus surgery (FESS) was performed. However, the patient's condition worsened, leading to a second hospitalization. Postoperative CT shows changes in the area of the right inferior rectus muscle below the eyeball compared with preoperative CT, and the initial CT also showed a suspicious space-occupying lesion in the right orbital inferior orbital fissure region. Imaging examinations suggested orbital cellulitis. The first histopathological examination of the local mucosa did not provide a definitive tumor diagnosis. The second pathological examination was conducted. The patient lost vision in the right eye before the second set of pathological results came out. Based on examination results, the blindness may be caused by compression of the optic nerve due to swelling of the orbital tissues. A second surgery was performed urgently to restore the patient's vision as soon as possible. Samples from six sites were sent for a third histopathological examination, and combined with the detection of Epstein-Barr virus (EBV), ENKTL was revealed, as in the second examination. The patient received gemcitabine/oxaliplatin (GemOx) chemotherapy. After five rounds of chemotherapy, he remains in remission, with no evidence that the lymphoma has recurred.

[CONCLUSIONS] It is relatively rare for ENKTL to involve intraocular or ocular adnexal tissues. The diagnosis is particularly challenging when patients present with facial swelling and periocular edema as the initial symptoms, especially when multiple CT and MRI examinations suggest the possibility of inflammatory lesions. When visiting our hospital, this patient presented with diplopia as the initial ophthalmologic complaint and ended up losing vision in the right eye, which was another "take-away" lesson of this case.