Nitrogen mustard gel-induced inflammation triggers lymphomatoid papulosis in patients with mycosis fungoides.

Lymphomatoid papulosis (LyP) is a paraneoplastic primary cutaneous CD30+ lymphoproliferative disorder (LPD) that has been associated with malignant lymphomas, most commonly mycosis fungoides (MF). We observed 10 patients with MF who developed severe inflammation after using nitrogen-mustard (NM) gel from 1 to 8 months and who developed LyP. We hypothesized that NM gel produced local inflammation, which induced CD30 expression in malignant T cells in situ leading to the appearance of LyP papules. The high frequency of induction of LyP lesions in patients with severe inflammation while on treatment with NM gel suggests an association between inflammatory stimuli and development of LyP. Our observation provides insight into the pathogenesis of CD30+ LPD.