Lymphomatoid papulosis

Lymphomatoid papulosis (LyP) is a rare skin disorder.

Lymphomatoid papulosis
Specialty	Dermatology

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]

Presentation

It can appear very similar to anaplastic large cell lymphoma.^[3] Type "A" is CD30 positive, while type "B" is CD30 negative.^[4]

It has been described as "clinically benign but histologically malignant."^[5]

Types of lymphomatoid papulosis^[6]

A	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.

Treatment

It may respond to methotrexate or PUVA.^[7]

Prognosis

It can evolve into lymphoma.^[8]

See also

• Cutaneous T-cell lymphoma
• Parapsoriasis
• Secondary cutaneous CD30+ large cell lymphoma
• List of cutaneous conditions