Extranodal NK-/T-cell Lymphoma, Nasal Type



Extranodal NK-/T-cell Lymphoma, Nasal Type


L. Jeffrey Medeiros, MD










CT scan shows an almost completely opacified maxillary sinus and thickening of mucosa in the nasopharynx. This patient was shown to have extranodal NK/T-cell lymphoma, nasal type.






Extranodal NK/T-cell lymphoma, nasal type. Biopsy from the maxillary sinus shows extensive coagulative necrosis (left).


TERMINOLOGY


Synonyms



  • Polymorphic reticulosis


  • Malignant midline reticulosis


  • Angiocentric T-cell lymphoma


  • Angiocentric immunoproliferative lesion



    • Term is not completely synonymous but includes nasal-type extranodal NK/T-cell lymphoma


Definitions



  • Predominantly extranodal lymphoma of either natural killer-cell (NK) or T-cell lineage



    • Characterized by necrosis, cytotoxic immunophenotype, and Epstein-Barr virus (EBV) infection


    • Vascular destruction is common


ETIOLOGY/PATHOGENESIS


Infectious Agents



  • EBV is consistently present in these neoplasms, suggesting its involvement in pathogenesis



    • EBV is usually type A


Epidemiology



  • Disease is common in Asia and in Native Americans of Central and South America


  • Disease is rare in United States, but its incidence has risen since 1992


CLINICAL ISSUES


Presentation



  • Mass that is nasal or extranasal



    • Nasal cases are usually defined as a neoplasm involving upper aerodigestive tract



      • Nasal cavity, nasopharynx, paranasal sinuses, palate


      • Patients suffer from obstruction, epistaxis, or midline destructive lesion


      • These neoplasms can disseminate


    • Extranasal cases are defined as neoplasm involving any site but without nasal involvement



      • Skin is most common extranasal site


      • Other sites: Testis, gastrointestinal tract, kidney, salivary glands


      • Primary involvement of lymph nodes is rare but has been reported


      • Bone marrow obtained as part of staging can be involved


Natural History



  • Extranodal nasal-type NK/T-cell lymphoma can disseminate



    • Regional lymph node involvement is not uncommon


    • Bone marrow involvement and leukemic phase can occur


    • These neoplasms can disseminate to virtually any anatomic site


Treatment



  • Options, risks, complications



    • Chemotherapy and radiation therapy are usually employed for nasal cases


    • Platelet-derived growth factor α overexpression shown by gene expression studies suggests role for imatinib


Prognosis



  • Patients with nasal-type extranodal NK/T-cell lymphoma, in general, have poor prognosis



    • Patients with extranasal tumors have poorest prognosis


    • Factors associated with poorer prognosis for nasal cases include




      • High International Prognostic Index (IPI) or Korean NK/T-cell Prognostic Score


      • Elevated C-reactive protein, anemia (< 11g/dL), or thrombocytopenia (< normal)


      • Large cells > 40%


      • Ki-67 (proliferation rate) > 50%


  • Korean NK/T Prognostic Score is based on



    • B symptoms, stage, serum LDH, and regional lymph nodes


IMAGE FINDINGS


General Features



  • Location



    • Nasal: Imaging studies show mass that can distort midline, displace adjacent organs, and destroy bone


    • Extranasal: Imaging studies usually show mass


MICROSCOPIC PATHOLOGY


Histologic Features



  • Nasal-type NK/T lymphoma has diffuse pattern; commonly associated with coagulative necrosis



    • Cell size is variable, ranging from small to large


    • Mitotic figures are usually identified; common in large tumors


    • In touch imprints, neoplastic cells can have azurophilic cytoplasmic granules


    • Angiocentricity and angiodestruction are common but not invariable



      • Less common in small biopsy specimens


    • Ulcer and superimposed inflammation are common at mucosal sites


    • Overlying epithelium at mucosal sites can show pseudoepitheliomatous hyperplasia


    • Erythrophagocytosis can complicate clinical course; can be fatal


  • Lymph node



    • Nasal-type NK/T preferentially involves paracortex ± medulla


  • Bone marrow



    • Staging bone marrow is involved in ˜ 10-20% of patients



      • Commonly an interstitial infiltrate without discrete aggregates


      • In situ hybridization for EBER helpful to detect disease


Cytologic Features



  • Nasal-type NK/T-cell lymphoma is uncommonly assessed by fine needle aspiration


  • Superimposed inflammation can make recognition of the disease challenging


ANCILLARY TESTS


Immunohistochemistry

Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Extranodal NK-/T-cell Lymphoma, Nasal Type

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