Primary natural killer cell lymphoma of the lacrimal sac

Primary lymphoid tumors of the lacrimal sac are quite rare, and all reporte d cases are of B-cell tumors with good prognosis. To our knowledge, this is the first case of primary natural killer (NK) cell lymphoma of the lacrima l sac. A 55-year-old woman presented with a lacrimal sac tumor, and histolo gical diagnosis of NK cell lymphoma was made. Although disease was initiall y localized to the right lacrimal sac, it invaded into the adjacent ethmoid al sinus before chemotherapy was initiated (clinical stage IIE). Epstein-Ba rr virus (EBV)-encoded small RNA (EBER) was detected in lymphoma cells by i n situ hybridization. Systemic chemotherapy combined with intrathecal chemo therapy followed by local radiotherapy was performed, and the patient achie ved complete remission. However, shortly after completion of chemoradiother apy, the lymphoma relapsed with rapid systemic dissemination. The disease w as refractory to chemotherapy, and the patient eventually succumbed due to sepsis.