Primary cutaneous Ki-1+ anaplastic large cell lymphoma: a morphologic, immunohistochemical and genetic study of an indolent case.

A 59-year-old woman with a large nodular ulcerative lesion on her neck was presented. She had a 3 year history of recurrent cutaneous nodules which spontaneously regressed before regional lymphadenopathies appeared. She has followed an indolent clinical course for seven years after the first overt lymphadenopathies appeared. Histological findings were compatible with anaplastic large cell lymphoma (ALCL). The tumor cells strongly expressed Ki-1 (CD30), HLA-DR, IL-2 receptor (CD25) and leukocyte common antigen. These findings led to the diagnosis of primary cutaneous Ki-1+ ALCL. Although the majority of the tumor cells did not express T-cell related antigens, the detection of monoclonal TCR gene rearrangement clearly established the T-cell lineage nature.