This case demonstrated nasal cavity and cutaneous tumor infiltrates consistent with previously described CD3-negative, CD56-positive NK-cell lymphoma of the upper aerodigestive tract.
Expression of NCAM could be regarded as responsible, in part, for the extranodal localization of lymphoma cells; expression of CD56 also might contribute to the definition of a subset of CD30+ lymphomas with distinctive clinicopathologic features.
The diagnosis of NK cell lymphoma was made on the basis of morphological and immunological characteristics (CD3-CD56+) found on skin biopsy of one of multiple skin nodules which subsequently developed in association with splenomegaly, thrombocytopenia and continuing neutropenia.
We also studied the expression of these molecules in 92 other cases of T-cell and natural killer (NK) cell neoplasms; 18 anaplastic large cell lymphomas (ALCLs); 63 CD4+ PTCLs; 10 CD56+ nasal lymphomas; and 1 NK-cell leukemia.
We consider that blastoid NK cell lymphoma is an extremely aggressive subtype of CD56-positive lymphomas, and high-dose chemotherapy with peripheral blood stem cell rescue should be included for the choice of the treatment.
This study indicates that chromosome aberrations in NK-cell lymphomas are restricted to the CD56+, CD3- and CD5- cell population and that NK-cell lymphomas are indeed derived from mature true NK cells and not from T lymphocytes.
Thus, there seems to be a useful distinction between the classical NK/T type of nasal lymphoma (CD56+/n-cdk6+/CD44-/TcR-GR-) and PTL (CD56-/n-cdk6-/CD44+/TcR-GR+) involving the nasal region.
The indolent behavior of this tumor indicates its similarity to other primary cutaneous CD30+ large cell lymphomas and its difference from other CD56+ lymphomas involving the skin, which often exhibit an aggressive clinical course.
When immunostained using paraffin embedded tissue, 6 upper aerodigestive lymphomas were negative forCD56 in which 4 cases lacked clonal TCR gene rearrangement.
A rare form of putative natural killer (NK) cell lymphoma called blastic NK cell lymphoma appears to be clinicopathologically distinctive in showing a homogenous lymphoblast, variable expression of CD2, CD4, CD56 and TdT, negative for surface CD3, T-cell receptor antigen, CD16, CD34 and lack of association with Epstein-Barr virus (EBV).