Abstract

Lymphomatoid papulosis (LyP) is a rare, benign lymphoproliferative disorder known to be associated with hematologic malignancies, including mycosis fungoides (MF) and anaplastic large cell lymphoma (ALCL). Polymerase chain reaction (PCR)-based methods to compare T-cell clonality in patients with concurrent LyP and MF have shown variable findings, with some showing shared monoclonal gene rearrangements in the LyP and MF lesions, suggesting a common origin. However, PCR-based clonality studies can have ambiguous results with limited sensitivity compared to next-generation sequencing (NGS)-based methods, and the clonal relationship between LyP and comorbid MF and ALCL remains unclear. We performed a retrospective analysis of patients with concurrent MF, LyP and/or ALCL who had clonality testing by NGS performed on their distinctive lesions of MF, LyP, and/or ALCL. We identified 15 patients who met inclusion criteria. 11 of 14 patients with both LyP and MF shared identical clonal sequences in their distinctive MF and LyP lesions. An additional 2 patients showed T-cell receptor (TCR) polyclonality in both their MF and LyP lesions, but with identical highest-frequency sequences in the two types of lesions. The last patient showed polyclonality with no top shared sequences in their MF and LyP lesions. A single patient with co-existing MF and ALCL showed polyclonality in samples from both types of lesions, but again the top two TCR sequences were identical in the MF and ALCL specimens. Ours is the largest single-institution study to date to examine T-cell clonality in patients with concurrent MF, LyP and/or ALCL and the first, to our knowledge, to employ NGS in such an analysis. Overall, 14 of 15 patients with concurrent MF and LyP or ALCL in our study showed shared clonal sequences in their biopsies from distinctive lesions of their MF and LyP or ALCL. Our results provide further evidence that these clinicopathologically distinct entities share a common cellular origin.

Financial Disclosure:
No current or relevant financial relationships exist.