CD2-, CD4+, CD56+ agranular natural killer cell lymphoma of the skin.

We present a case of CD56-positive cutaneous lymphoma with a clinical appearance resembling angiosarcoma. The biopsy specimen showed angiocentric infiltrates of small to medium-sized cells positive for CD4, CD45, and CD56 but negative for CD2, surface and cytoplasmic CD3, CD8, CD20, and CD57. There was no detectable clonal rearrangement of either TCRbeta or TCRgamma genes and no dense core granules in the cytoplasm. Epstein-Barr virus was not detected. The patient died of an unrelated disease 20 months after initial biopsy, although there was some response to interleukin-2, radiotherapy, and VP-16. The results suggest that our case does not precisely match the recently proposed variants of CD56-positive lymphoma, namely nasal T/natural killer cell lymphoma and blastic natural killer cell lymphoma. Agranular natural killer cell lymphomas similar to our case in the immunophenotype have been reported to be indolent and occur in the skin. These lymphomas may be a distinct subtype and have a predilection for involving the skin.