Abstract

Extranodal natural killer/T-cell lymphoma, nasal type (ENKTL-NT) is an aggressive lymphoproliferative disorder that typically presents in the upper aerodigestive tract and has a strong association with Epstein-Barr virus (EBV). Histologically, it is characterized by a dense, dermal infiltrate with geographic necrosis and angioinvasion. ENKTL-NT with extranasal disease and primary cutaneous ENKTL tend to present at more advanced stages and have a poor prognosis, highlighting the importance of early detection. Here, we describe a rare and fatal case of primary cutaneous ENKTL-NT with bone marrow involvement. The patient was a 57-year-old female with a complex medical history who presented to the hospital with persistent lightheadedness, subsequently found to have bilateral deep vein thrombosis, right pulmonary emboli, and thrombocytopenia. Dermatology was consulted for a scattered, erythematous, indurated rash on the bilateral lower extremities that had worsened over the past month. The skin biopsy showed an atypical T-cell infiltrate positive for EBV in-situ hybridization, consistent with ENKTL-NT. PET/CT revealed no nodal, nasal, or other organ involvement, suggesting a primary cutaneous presentation. A bone marrow biopsy showed involvement by NK/T-cell lymphoma and hemophagocytosis, which correlated clinically with the patient’s diagnosis of hemophagocytic lymphohistiocytosis. Ultimately, the patient developed progressive respiratory decline and passed away despite intervention. This case describes a cutaneous manifestation of ENKTL-NT without apparent nasal involvement, alongside adverse clinical features that predicted an unfavorable outcome. Primary cutaneous ENKTL-NT remains a diagnostic challenge given its rarity, aggressive nature, and similarities with other neoplasms, requiring interdisciplinary collaboration for diagnosis and treatment.