Lymphomatoid papulosis associated with Ki-1-positive anaplastic large cell lymphoma. A report of two cases and a review of the literature.

BACKGROUND: Lymphomatoid papulosis (LyP) is an uncommon disorder characterized by recurrent papulonodular cutaneous lesions that last from 4 to 5 weeks and often heal with hypopigmented or hyperpigmented scarring. Prognosis is varied, 10%-20% of patients have associated lymphomas: mycosis fungoides, T-cell immunoblastic lymphoma, or Hodgkin's disease, which can precede, occur simultaneously with, or follow the diagnosis of LyP. Anaplastic large cell lymphoma (ALCL) is histologically and phenotypically similar to LyP and also appears as part of this disease spectrum. Recent reports analyzing immunophenotype and T-cell receptor gene rearrangements in patients with both LyP and lymphoma suggest that they are derived from an identical T-cell clone, in the rare cases studied.
METHODS: The case histories of two patients with LyP in whom ALCL involving the skin and lymph nodes subsequently developed are presented.
RESULTS: Intensive treatment with combination chemotherapy resulted in complete remission of ALCL in both patients, followed by the recurrence of LyP. A spontaneous remission of LyP occurred in the initial patient described, whereas the second patient suffered recurrences of both LyP and ALCL despite therapy.
CONCLUSIONS: The case histories presented illustrate the immunophenotypic and morphologic similarities of ALCL and LyP, and the difficulties in distinguishing between them. Both entities can occur in a single patient, as shown by this report, supporting a close relationship between these processes. However, different clinical behavior and response to therapy are apparent, which connote a fundamental difference in the biologies of these neoplastic disorders. A review of the literature concerning the association between these entities is provided.