Progression of cutaneous B-cell pseudolymphoma to cutaneous B-cell lymphoma

Debates regarding nosology and clonality surround the entity known as cutaneous pseudolymphoma and its questionable transformation to frank cutaneous lymphoma. The relevance of these arguments is important, not only from a diagnostic standpoint, but also for making inferences based upon behavior, prognosis, and treatment.

Our goal was to demonstrate further evidence of progression from cutaneous pseudolymphoma to malignant lymphoma while at the same time advocating a comprehensive plan for evaluation, treatment, and followup of these patients.

A retrospective review was conducted of four patients initially considered to have cutaneous B-cell pseudolymphoma (CBPL) and who were later treated for primary cutaneous B-cell lymphoma (CBCL). A review of the literature of cases suggesting progression to malignant lymphoma from precursor lesions was also performed.

Four patients initially diagnosed with CBPL by a combination of histologic, immunophenotypic, and gene rearrangement criteria had a progressive clinical course that, over a range of 17-51 months, evolved into CBCL. All patients had a comprehensive systemic workup to rule out the possibility of extracutaneous disease and were treated with local radiation therapy and close followup. There has been no evidence of extracutaneous disease with an average followup of 14 months.

The potential for certain cutaneous pseudolymphomas to progress to CBCL is real. The combination of histologic and immunophenotypic criteria, along with the clinical picture, remains the best way to judge the aggressiveness of the lesion. Gene rearrangement studies, whether performed by Southern blot or polymerase chain reaction (PCR), are of limited value and should be used to support the overall clinicopathologic picture. Radiation therapy of these patients should be thought of early in the management plan and is a very successful form of treatment when combined with close followup.