Disseminated Extranodal NK/T-Cell lymphoma, Presenting as an Orbital Mass.

An 84-year-old male patient presented with decreased vision of 20/300 in the right eye, with additional painless upper eyelid fullness, hypoglobus, severe limitation of ocular motility, and conjunctival chemosis of the right eye for several months duration (panel A). He was referred after failing to respond to a trial of oral corticosteroids for presumed orbital myositis. MRI revealed an enlarged enhancing lacrimal gland (arrow), extraocular muscles, and mucosal thickening of the ethmoid sinus (arrowhead) on the right side (panel B). Lacrimal gland biopsy demonstrated medium-sized atypical lymphocytes with irregular nuclear contours, scant-to-moderate amounts of cytoplasm, and brisk mitotic figures (arrow) (panel C, hematoxylin-eosin, ×630), which expressed cytotoxic and natural killer-cell markers CD56 (panel D, ×400), perforin, and T-cell intracellular antigen 1, and were CD4-positive and CD8-negative. Neoplastic cells were positive for Epstein–Barr virus-encoded RNA by in situ hybridization (panel E, ×400). Clinical, morphologic, and immunophenotypic findings were compatible with extranodal natural killer/T-cell lymphoma (natural killer/T-cell lymphoma, nasal type). Optical coherence tomography revealed diffuse choroidal thickening with an undulating anterior border (sea-sick choroid) (arrow), compatible with choroidal involvement by lymphoma (panel F). Positron emission tomography scan showed significantly increased activity in the regional and distal lymph nodes and in multiple bones, compatible with disseminated disease. The patient succumbed to disease shortly after diagnosis. This case highlights the importance of prompt and accurate diagnosis of natural killer/T-cell lymphoma, nasal type, which can present with orbital and ocular involvement simulating an inflammatory process.FIG