Aims: To determine incidence and risk factors for developing lymphoma in patients with lymphomatoid papulosis (LyP), and to identify putative triggers amenable to treatment.
Methods: The prognostic effect of severity of LyP, viral infection by history or serology, beta-2-microglobulin level, lactic dehydrogenase (LDH) level, and CD4 : CD8 ratio were evaluated using logistic regression models. Responses to prophylactic or palliative treatment were assessed.
Results: In total, 84 patients (38 men, 46 women, median age at diagnosis 48.5 years) were identified. Of these, 34 (40%) were also diagnosed with one or more lymphomas: 16 (19%) had mycosis fungoides, 15 (17%) had primary cutaneous anaplastic large-cell lymphoma (pcALCL), 2 had both MF and pcALCL, and 1 had MF with large cell transformation and 1 had peripheral T-cell lymphoma. Of the 61 people presenting with LyP alone, only 11 (18%) subsequently developed lymphoma, with a median onset of 17.6 years (95% CI: 4, not obtained). Men were 2.5 times more likely than women to develop lymphoma (P = 0.04). Exposure to Epstein-Barr virus (EBV) was associated with an increase in incidence of 4.8 times (P = 0.16). Treatment for a putative infectious trigger resulted in improvement for 15 of 24 patients (63%).
Conclusion: Referral bias may explain the higher (40%) incidence of lymphoma in this population of LyP patients, compared with the 10-20% incidence commonly cited in the literature. In the subset of patients presenting with LyP alone, only 18% later developed lymphoma. Male patients or patients with prior EBV infection may have a higher risk for developing lymphoma, and some patients improved with treatment of putative infectious triggers.