[Primary adrenal NK/T cell lymphoma: a clinicopathologic analysis of six cases].

Objective: To investigate the clinicopathologic features of primary adrenal NK/T cell lymphoma (PANKL). Methods: Six cases of PANKL were collected at Henan Provincial People's Hospital from January 2000 to December 2021. The clinicopathologic features including morphology, immunophenotype, treatment and prognosis were retrospectively analyzed, and relevant literature was reviewed. Results: There were two males and four females. The median age was 63 years (ranged from 57 to 68 years). The tumors involved bilateral adrenal glands in 4 cases and unilateral adrenal gland in 2 cases. The main clinical symptom was low back pain without obvious cause. Serum lactate dehydrogenase (LDH) is elevated in five cases. The imaging feature was rapidly enlarging mass initially confined to unilateral/bilateral adrenal glands. Morphologically, the lymphoid cells were mainly medium-sized with a diffuse growth pattern. Coagulative necrosis and nuclear fragmentation were common. Angioinvasion was seen. Immunophenotypically, the neoplastic cells were positive for CD3, CD56 and TIA-1 while CD5 was negative in 5 cases. All cases were positive for EBER by in situ hybridization with more than 80% proliferative activity by Ki-67. Four cases received chemotherapy, one case underwent surgery, and one case underwent surgery with chemotherapy. Follow-up was done in 5 cases; one case was lost to follow-up. Three patients died with a median survival of 11.6 months (3-42 months). Conclusions: PANKL is rare with highly aggressive clinical presentation and poor prognosis. Accurate diagnosis entails correlation of histomorphology, immunohistochemistry, EBER in situ hybridization and clinical history.