Guidelines on Diagnosis and Treatment of Malignant Lymphomas

Mature T Cell and
NK Cell Neoplasms
EXTRANODAL NK/T-CELL
LYMPHOMA, NASAL TYPE
Definition and Incidence
Extranodal NK/T cell lymphoma, nasal type is a predominantly
extranodal lymphoma characterised by a broad morphologic
spectrum. The lymphoma typically presents as a locally
destructive proliferative lesion. The disease is most common in
Asia, Mexico, Central and South America. Males predominate
and the median age of presentation is 50 to 55 years. These
lymphomas have also been described in patients
immunosuppressed following organ transplantation.
ICD-O Code 9719/3
Clinical Presentation
The commonest site is the nasal cavity. Identical neoplasms
may be seen in other extranodal sites, including the nasopharynx,
palate, skin, soft tissue, gastrointestinal tract and testis. Patients
typically present with facial swelling and or mid-line facial
destruction and the disease has an aggressive course. It is
localised (stage I and II) in 80% at presentation but may
disseminate to the skin, gastrointestinal tract, orbit, CNS or testis.
Pathology and Genetics
This lymphoma is described as an angiocentric and
angiodestructive, proliferative lesion. Fibrinoid changes, coagulative
necrosis and apoptotic bodies are common. There is a broad
spectrum of tumour cell morphology. Cells may be small, medium,
large or anaplastic. They may have irregular nuclei which may be
elongated, and nucleoli are generally inconspicuous. Mitotic figures
are easily found. There may be a prominent inflammatory infiltrate.
Phenotype
The most common phenotype is CD2+, CD3-, CD56+, CD7-,
Granzyme +. Other T and NK cell antigens are usually negative,
including CD4, CD5, CD8, CD16 and CD57.
Genetics
T-Cell receptor and immunoglobulin genes are in germline
configuration in the majority of cases, although T-cell receptor
gene rearrangement may be detected. EBV genome is detected in
tumour tissue using in situ hybridization for EBV-encoded RNA.
Staging
As for other high grade lymphomas.
Recommended Investigations
As for other high grade lymphomas but should include in
addition: a CT scan and MRI of nasal sinuses and brain.
Lumbar puncture with cytology for malignant cells should
also be performed.
Prognostic Factors / Index
The prognosis is variable, with some patients achieving
complete responses to treatment, and others dying of
progressive, disseminated disease. Extranodal involvement in
nasal disease or disease occurring outside the nasal cavity is
very aggressive and associated with a short survival.
45