Primary colon natural killer (NK)/T-cell lymphoma, nasal type, with perforations: a case report and literature review

Extranodal natural killer (NK)/T-cell lymphoma-nasal type (ENKTL-NT) is a rare, aggressive subtype of non-Hodgkin's lymphoma associated with Epstein-Barr virus (EBV) infection and has a poor prognosis. ENKTL-NT primarily involves the nasal cavity, and the colon as the primary site has rarely been reported. Its lack of a characteristic clinical presentation makes early diagnosis difficult to diagnose early, and misdiagnosis is common without the use of immunohistochemistry of specimens. To further understand this rare solid tumor, we report a case in a 51-year-old male patient admitted to hospital with abdominal pain as the primary symptom. A provisional diagnosis of gastrointestinal perforation was made on the basis of enhanced computed tomography of the abdomen, and emergency surgery was performed. However, 58 days after discharge, he suffered a second colonic perforation, underwent emergency surgery and was diagnosed with primary colonic ENKTL-NT based on the immunohistochemical results of the surgical specimen. He was transferred to the oncology department for chemotherapy after recovery from surgery, with gemcitabine, oxaliplatin, and pegaspargase as the chemotherapy regimen. To date, he has completed 11 courses of chemotherapy, and is now in a significantly improved general condition with no signs of tumor recurrence. We also reviewed and compared the literature related to primary colonic ENKTL-NT.

Development of Extranodal NK/T-cell Lymphoma Nasal Type in Cerebrum Following Epstein-Barr Virus-positive Uveitis

A 74-year-old woman developed bilateral uveitis with high Epstein-Barr virus (EBV) DNA load in the vitreous fluid without lymphoma cells. Four years after the onset, T2-weighted contrast-enhanced MRI revealed hyperintense lesions in the right occipital and parietal lobe. A biopsy resulted in the diagnosis of extranodal NK/T-cell lymphoma nasal type (ENKL). The repeat region of LMP1, an EBV gene, detected in the brain lesion was identical to that detected in the vitreous fluid. ENKL of the central nervous system is quite rare, and the pathogenesis has not been determined. The lymphoma in this case might have been closely associated with the EBV-positive uveitis.

Genetic alterations of JAK/STAT cascade and histone modification in extranodal NK/T-cell lymphoma nasal type

Extranodal NK/T-cell lymphoma nasal type (ENKL) is a rare type of non-Hodgkin lymphoma that more frequently occurs in East Asia and Latin America. Even though its molecular background has been discussed in the last few years, the current knowledge does not explain the disease pathogenesis in most cases of ENKL. Here, we performed multiple types of next-generation sequencing on 34 ENKL samples, including whole-exome sequencing (9 cancer tissues and 4 cancer cell lines), targeted sequencing (21 cancer tissues), and RNA sequencing (3 cancer tissues and 4 cancer cell lines). Mutations were found most frequently in 3 genes, STAT3, BCOR, and MLL2 (which were present in 9, 7, and 6 cancer samples, respectively), whereas there were only 2 cases of JAK3 mutation. In total, JAK/STAT pathway- and histone modification-related genes accounted for 55.9% and 38.2% of cancer samples, respectively, and their involvement in ENKL pathogenesis was also supported by gene expression analysis. In addition, we provided 177 genes upregulated only in cancer tissues, which appear to be linked with angiocentric and angiodestructive growth of ENKL. In this study, we propose several novel driver genes of ENKL, and show that these genes and their functional groups may be future therapeutic targets of this disease.