The patient with recurrent periorbital cellulitis: A sinister NK cell tumor lymphoma.

Purpose: We describe a rare case of periorbital cellulitis caused by NK cell lymphoma. Observations: An 18-year-old female presented with left eye periorbital swelling and watering eye for 2 months. She was initially diagnosed with preseptal cellulitis where she had received multiple courses of intravenous antibiotics with no improvement. MRI demonstrated nasolacrimal duct obstruction. The working diagnosis was preseptal cellulitis secondary to dacrocystitis. She was admitted and initiated on intravenous antibiotics. The swelling improved and she was listed for a dacryocystorhinostomy as an outpatient. She subsequently represented with recurrence. A CT orbit and sinus was undertaken which showed severe mucosal disease, and thinning of medial wall of the left orbit. Otolaryngology review was requested, and a functional endoscopic sinus surgery was undertaken with biopsies. Histology demonstrated infiltrative malignancy with Angio centricity and necrosis. The diagnosis was extranodal Natural killer/T cell lymphoma (ENTKL), nasal type. Conclusions and importance: Primary peri-orbital and intraocular ENTKL has rarely been reported. A high index of suspicion should be maintained in a patient presenting with non-resolving pre septal cellulitis, and a CT sinus should always be considered. Pre- or intraoperative suspicion of malignancy should indicate biopsy, with rapid referral for multidisciplinary team management given the aggressive nature and likely outcome.