Nasal Type Extranodal Natural Killer/T (NK/T) Cell Lymphoma Presenting as Periorbital Cellulitis: A Case Report.

BACKGROUND Extranodal lymphoma of the paranasal sinuses is a rare clinical entity seen in only 5-8% of extranodal lymphomas of the head and neck. Nasal natural killer/T cell lymphoma (Nasal NKTCL), which is a subtype of peripheral T cell lymphoma, constitutes about 1.4% of all lymphomas. NKTCL is usually diagnosed at a late stage because it presents with nonspecific symptoms in the early stages. CASE REPORT We report the case of a 25-year-old male patient who presented with periorbital swelling treated as fungal sinusitis but proven to have NKTCL. We review the literature and discuss the clinical manifestations of the disease, its relation to EBV virus, the histological and radiological characteristics, the prognostic indicators, and treatment options. This case report shows physicians that NKTCL lymphoma can present as periorbital cellulitis, although few similar cases are found in the literature. CONCLUSIONS NKTCL is a destructive midline tumor that should be kept in mind as a differential diagnosis of paranasal sinus lesions to help in early diagnosis, which can improve the prognosis.