Lymphomatoid papulosis (LyP) is a rare skin disorder.

The overall prevalence rate of lymphomatoid papulosis is estimated at at least 1.2 cases per 1,000,000 population.

[1] This rare condition has only been studied in depth since 1968.

[2] It can appear very similar to anaplastic large cell lymphoma.

[4] It has been described as "clinically benign but histologically malignant.