Extranodal NK/T-cell lymphoma, nasal type (ENKTL) is a rare but extremely aggressive non-Hodgkin lymphoma nearly always associated with EBV. Originates from NK cells or cytotoxic T cells. Particularly endemic in East Asia, Southeast Asia, Central and South America. Most commonly involves the nasal cavity and nasopharynx (80% nasal type); extranasal involvement may occur in skin, GI, testis, and lymph nodes. Characteristically presents with midface destruction ('lethal midline granuloma'), nasal obstruction, epistaxis, and facial swelling. Histologically characterized by angiocentric/angiodestructive growth pattern, coagulative necrosis, and CD56+/CD3ε+ immunophenotype. Lymph node involvement is usually from spread of nasal disease or rarely as primary nodal form. Prognosis is poor — 5-year survival 50-70% for nasal type, 20-30% for extranasal type.
Age Range
30-70
Peak Age
50
Gender
Male predominant
Prevalence
Rare
ENKTL develops through malignant transformation of EBV-infected NK cells or cytotoxic T cells. EBV's latent membrane protein-1 (LMP1) oncoprotein activates NF-κB, JAK/STAT, and PI3K/AKT signaling pathways, increasing cell proliferation and providing apoptosis resistance. Malignant cells show angiocentric growth pattern — infiltrating and surrounding vessel walls. Angiodestruction (vessel wall destruction) results from malignant and reactive inflammatory cells damaging vascular endothelium — cytotoxic granules such as perforin and granzyme destroy vessel walls. This vascular damage leads to coagulative necrosis and tissue infarction — in the nasal region this mechanism causes bone and cartilage destruction creating midface collapse. On imaging, the nasal/paranasal aggressive destructive mass and coagulative necrosis (low-density areas) reflect this pathophysiological process. Bone destruction on CT results from direct bone invasion + vascular necrosis combination. Diffusion restriction on DWI indicates dense proliferation of malignant cells. Intense FDG uptake on PET-CT reflects the high glycolysis rate of aggressive malignant cells.
Aggressive soft tissue mass destroying nasal septum, turbinates and surrounding bone/cartilage structures in the nasal cavity with ipsilateral cervical lymphadenopathy, particularly in an Asian patient, is pathognomonic for ENKTL.
On contrast-enhanced CT, a heterogeneously enhancing aggressive soft tissue mass is seen in the nasal cavity and/or nasopharynx. Destruction of nasal septum, turbinates, maxillary sinus walls, and orbital floor may accompany. Necrotic low-density areas are common. Ipsilateral cervical (Level I-III) enlarged, heterogeneously enhancing and possibly necrotic lymph nodes may accompany. Mass may show invasion of surrounding structures (orbit, premaxillary soft tissues, floor of mouth).
Report Sentence
CT demonstrates an aggressive heterogeneous mass with bone destruction in the nasal cavity and ipsilateral cervical necrotic lymphadenopathy; findings are consistent with ENKTL.
On B-mode US, ipsilateral cervical enlarged lymph nodes are seen — heterogeneous internal structure, central necrosis (anechoic/hypoechoic area), loss of hilum, and round shape.
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On US, ipsilateral cervical enlarged, heterogeneous lymph nodes with central necrosis and loss of hilum are noted.
On Doppler, peripheral and chaotic vascularity pattern in enlarged lymph nodes. Necrotic areas are avascular. This pattern reflects aggressive malignant infiltration.
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Doppler demonstrates peripheral chaotic vascularity and avascular necrotic areas in enlarged lymph nodes.
On DWI, nasal mass and metastatic lymph nodes demonstrate marked diffusion restriction — ADC values generally in 0.5-0.9 × 10⁻³ mm²/s range. Necrotic areas show higher ADC values.
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On DWI, marked diffusion restriction (ADC: ___×10⁻³ mm²/s) in nasal mass and cervical lymph nodes, consistent with aggressive lymphoproliferative disease.
On FDG PET-CT, nasal mass and involved lymph nodes demonstrate very intense FDG uptake (SUVmax generally 10-25+). PET-CT plays a critical role in staging, treatment response, and recurrence monitoring. Extranasal involvement (skin, GI, testis, CNS) may be detected.
Report Sentence
FDG PET-CT demonstrates very intense FDG uptake (SUVmax: ___) in nasal mass and cervical lymph nodes; consistent with ENKTL.
On T2, nasal mass and involved lymph nodes show heterogeneous signal — viable tumoral area hyperintense, necrotic area variable signal. Nasal bone and cartilage destruction is evaluated.
Report Sentence
On MRI T2, nasal mass demonstrates heterogeneous signal reflecting coexistence of viable tumoral and necrotic areas.
Criteria
Nasal cavity, nasopharynx, paranasal sinuses, palate involvement. Most common form (80%).
Distinct Features
Midface destruction characteristic. Radiotherapy is primary treatment. 5-year survival 50-70%.
Criteria
Primary involvement of skin, GI, testis, or lymph node. No nasal involvement. More aggressive course.
Distinct Features
Prognosis much worse — 5-year survival 20-30%. Chemotherapy-based treatment. Widespread involvement on PET-CT.
Criteria
Leukemic variant in ENKTL spectrum. Bone marrow, peripheral blood, liver and spleen involvement. Hepatosplenomegaly, pancytopenia, DIC.
Distinct Features
Fulminant course, median survival 2-3 months. Hepatosplenomegaly dominant on CT, focal masses less prominent.
Distinguishing Feature
In nasopharyngeal SCC bone destruction is less aggressive and mass is generally better defined; in ENKTL midline destruction and necrosis are more widespread. SCC may be EBV-associated (nasopharynx) but CD56 negative.
Distinguishing Feature
LYG is also angiodestructive and EBV-associated but lung is primary site; ENKTL nasal/midface involvement predominates. LYG is B-cell, ENKTL is NK/T-cell origin.
Distinguishing Feature
DLBCL may involve nasal region but midface destruction is not as aggressive as ENKTL. DLBCL is CD20+/CD56-, ENKTL is CD56+/CD20-.
Distinguishing Feature
Nasal involvement very rare in TB and bone destruction more slowly progressive. Rim-enhancing necrotic LAP dominant in TB while solid heterogeneously enhancing aggressive mass dominant in ENKTL.
Urgency
emergentManagement
medicalBiopsy
NeededFollow-up
3-monthENKTL is an extremely aggressive lymphoma requiring emergent treatment. Diagnosis by nasal biopsy — deep biopsy needed due to abundant necrotic tissue. CD56+, cytoplasmic CD3ε+, EBV-EBER ISH+ on immunohistochemistry is pathognomonic. For nasal type, radiotherapy (50 Gy+) + concurrent chemotherapy (DeVIC, SMILE or L-asparaginase based regimens) is standard. For extranasal type, chemotherapy is primary — L-asparaginase containing regimens (SMILE, AspaMetDex) preferred. PET-CT critical for treatment response and recurrence monitoring. Plasma EBV DNA PCR used as biomarker for disease activity monitoring. Prognosis: nasal type stage I-II 50-70%, extranasal type 20-30%.
Extranodal NK/T-cell lymphoma is an aggressive disease. Early-stage (I-II) disease is treated with concurrent chemoradiotherapy (CCRT) + L-asparaginase-based regimens. Advanced stage uses SMILE or P-GEMOX regimens. Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening complication. PD-L1 expression may be high, and checkpoint inhibitors are being investigated. Serum EBV DNA level is used for treatment response monitoring.