Lymphomatoid papulosis (LyP) is a rare skin disorder.
Prevalence
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]
Wedge-shaped clusters of large atypical lymphocytes that are CD30+, interspersed with a mixed inflammatory infiltrate of neutrophils, histiocytes, and eosinophils.
B
Similar to mycosis fungoides, with bandlike infiltrate and epidermotropism of smaller atypical lymphocytes that may be CD30-.
C
Similar to cutaneous anaplastic large-cell lymphoma, with larger clusters or sheets of large anaplastic CD30+ cells without the interspersed mixed infiltrate of Type A.
D
Similar to CD8+ epidermotropic cutaneous T-cell lymphoma, with large CD8+ and CD30+ lymphocytes that often stain with cytotoxic markers (TIA-1, granzyme, perforin).
E
Angioinvasive with small to large angiocentric CD30+ atypical lymphocytes that invade walls of small to medium vessels in dermis or subcutaneously.
F
Perifollicular infiltrates of CD30+ atypical cells with folliculotrophism with or without follicular mucinosis.