Secondary ALK negative anaplastic large cell lymphoma in a patient with lymphomatoid papulosis of 40 years duration.

A 49 year-old man presented to our clinic. He had a history of lymphomatoid papulosis since childhood. At age 44, regional lymph node manifestation of anaplastic lymphoma kinase (ALK) anaplastic large cell lymphoma (ALCL) developed. Chemotherapy resulted in complete remission of the lymphadenopathy. Four years later, systemic relapse was detected which was refractory to therapy. Histology and immunohistochemistry showed congruent characteristics of multiple skin and lymph node biopsies: diffuse mixed infiltrate with large, anaplastic CD30 cells. Immunophenotype and microscopic morphology suggested a common origin of the different manifestations-however, this could not be proven due to lack of T-cell receptor (TCR) gamma gene rearrangement in most of the samples. The diagnosis of ALK-negative systemic ALCL with cutaneous symptoms was set up at the second flare up, however, the possibility of primary cutaneous ALCL was not excluded steadily. Lymphomatoid papulosis, primary cutaneous ALCL, and systemic ALK ALCL are 3 different entities but the separation of them cannot be solved without distinctive diagnostic tools.